Patent Publication Number: US-2022219452-A1

Title: Print component with memory array using intermittent clock signal

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a U.S. Continuation Application of National Stage application Ser. No. 16/767,914, filed May 28, 2020, entitled “PRINT COMPONENT WITH MEMORY ARRAY USING INTERMITTENT CLOCK SIGNAL” which is a U.S. National Stage Application of PCT Application No. PCT/US2019/016727, filed Feb. 6, 2019, entitled “PRINT COMPONENT WITH MEMORY ARRAY USING INTERMITTENT CLOCK SIGNAL”. 
    
    
     BACKGROUND 
     Some print components may include an array of nozzles and/or pumps each including a fluid chamber and a fluid actuator, where the fluid actuator may be actuated to cause displacement of fluid within the chamber. Some example fluidic dies may be printheads, where the fluid may correspond to ink or print agents. Print components include printheads for 2D and 3D printing systems and/or other high precision fluid dispense systems. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block and schematic diagram illustrating a print component, according to one example. 
         FIG. 2  is a block and schematic diagram illustrating a print component, according to one example. 
         FIG. 3  is a block and schematic diagram generally illustrating portions of a primitive arrangement, according to one example. 
         FIG. 4A  is a schematic diagram generally illustrating data segments, according to one example. 
         FIG. 4B  is a schematic diagram generally illustrating data segments, according to one example. 
         FIG. 5  is a block and schematic diagram illustrating a print component, according to one example. 
         FIG. 6  is a block and schematic diagram illustrating a print component, according to one example. 
         FIG. 7  is a schematic diagram illustrating a block diagram illustrating one example of a fluid ejection system. 
         FIG. 8  is a flow diagram illustrating a method of operating a print component, according to one example. 
     
    
    
     Throughout the drawings, identical reference numbers designate similar, but not necessarily identical, elements. The figures are not necessarily to scale, and the size of some parts may be exaggerated to more clearly illustrate the example shown. Moreover the drawings provide examples and/or implementations consistent with the description; however, the description is not limited to the examples and/or implementations provided in the drawings. 
     DETAILED DESCRIPTION 
     In the following detailed description, reference is made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration specific examples in which the disclosure may be practiced. It is to be understood that other examples may be utilized and structural or logical changes may be made without departing from the scope of the present disclosure. The following detailed description, therefore, is not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims. It is to be understood that features of the various examples described herein may be combined, in part or whole, with each other, unless specifically noted otherwise. 
     Examples of fluidic dies may include fluid actuators. The fluid actuators may include thermal resistor based actuators (e.g. for firing or recirculating fluid), piezoelectric membrane based actuators, electrostatic membrane actuators, mechanical/impact driven membrane actuators, magneto-strictive drive actuators, or other suitable devices that may cause displacement of fluid in response to electrical actuation. Fluidic dies described herein may include a plurality of fluid actuators, which may be referred to as an array of fluid actuators. An actuation event may refer to singular or concurrent actuation of fluid actuators of the fluidic die to cause fluid displacement. An example of an actuation event is a fluid firing event whereby fluid is jetted through a nozzle. 
     In example fluidic dies, the array of fluid actuators may be arranged in sets of fluid actuators, where each such set of fluid actuators may be referred to as a “primitive” or a “firing primitive.” The number of fluid actuators in a primitive may be referred to as a size of the primitive. In some examples, the set of fluid actuators of each primitive are addressable using a same set of actuation addresses, with each fluid actuator of a primitive corresponding to a different actuation address of the set of actuation addresses, with the addresses being communicated via an address bus. In some examples, a fluidic actuator of a primitive will actuate (e.g., fire) in response to a fire signal (also referred to as a fire pulse) based on actuation data corresponding to the primitive (sometimes also referred to as nozzle data or primitive data) when the actuation address corresponding to the fluidic actuator is present on the address bus. 
     In some cases, electrical and fluidic operating constraints of a fluidic die may limit which fluid actuators of each primitive may be actuated concurrently for a given actuation event. Primitives facilitate addressing and subsequent actuation of fluid actuator subsets that may be concurrently actuated for a given actuation event to conform to such operating constraints. 
     To illustrate by way of example, if a fluidic die comprises four primitives, with each primitive including eight fluid actuators (with each fluid actuator corresponding to a different address of a set of addresses 0 to 7), and where electrical and fluidic constraints limit actuation to one fluid actuator per primitive, a total of four fluid actuators (one from each primitive) may be concurrently actuated for a given actuation event. For example, for a first actuation event, the respective fluid actuator of each primitive corresponding to address “ 0 ” may be actuated. For a second actuation event, the respective fluid actuator of each primitive corresponding to address “5” may be actuated. As will be appreciated, such example is provided merely for illustration purposes, with fluidic dies contemplated herein may comprise more or fewer fluid actuators per primitive and more or fewer primitives per die. 
     Example fluidic dies may include fluid chambers, orifices, and/or other features which may be defined by surfaces fabricated in a substrate of the fluidic die by etching, microfabrication (e.g., photolithography), micromachining processes, or other suitable processes or combinations thereof. Some example substrates may include silicon based substrates, glass based substrates, gallium arsenide based substrates, and/or other such suitable types of substrates for microfabricated devices and structures. As used herein, fluid chambers may include ejection chambers in fluidic communication with nozzle orifices from which fluid may be ejected, and fluidic channels through which fluid may be conveyed. In some examples, fluidic channels may be microfluidic channels where, as used herein, a microfluidic channel may correspond to a channel of sufficiently small size (e.g., of nanometer sized scale, micrometer sized scale, millimeter sized scale, etc.) to facilitate conveyance of small volumes of fluid (e.g., picoliter scale, nanoliter scale, microliter scale, milliliter scale, etc.). 
     In some examples, a fluid actuator may be arranged as part of a nozzle where, in addition to the fluid actuator, the nozzle includes an ejection chamber in fluidic communication with a nozzle orifice. The fluid actuator is positioned relative to the fluid chamber such that actuation of the fluid actuator causes displacement of fluid within the fluid chamber that may cause ejection of a fluid drop from the fluid chamber via the nozzle orifice. Accordingly, a fluid actuator arranged as part of a nozzle may sometimes be referred to as a fluid ejector or an ejecting actuator. 
     In some examples, a fluid actuator may be arranged as part of a pump where, in addition to the fluidic actuator, the pump includes a fluidic channel. The fluidic actuator is positioned relative to a fluidic channel such that actuation of the fluid actuator generates fluid displacement in the fluid channel (e.g., a microfluidic channel) to convey fluid within the fluidic die, such as between a fluid supply and a nozzle, for instance. An example of fluid displacement/pumping within the die is sometimes also referred to as micro-recirculation. A fluid actuator arranged to convey fluid within a fluidic channel may sometimes be referred to as a non-ejecting or microrecirculation actuator. In one example nozzle, the fluid actuator may comprise a thermal actuator, where actuation of the fluid actuator (sometimes referred to as “firing”) heats the fluid to form a gaseous drive bubble within the fluid chamber that may cause a fluid drop to be ejected from the nozzle orifice. As described above, fluid actuators may be arranged in arrays (such as columns), where the actuators may be implemented as fluid ejectors and/or pumps, with selective operation of fluid ejectors causing fluid drop ejection and selective operation of pumps causing fluid displacement within the fluidic die. In some examples, the array of fluid actuators may be arranged into primitives. 
     Some printheads receive data in the form of data packets, sometimes referred to as fire pulse groups or a fire pulse group data packets, where each data packet includes a head portion and a body portion. In some examples, the head portion includes a sequence of start bits and configuration data for on-die functions such as address bits for address drivers, and fire pulse data for fire pulse selection, for example. The body portion of the packet includes primitive data, such as actuator data and/or memory data, that selects which nozzles corresponding to address represented by the address bits in the primitives will be actuated (or fired) and, in some examples, represents data to be written to memory elements of memory arrays associated the primitives. The fire pulse group data pack concludes with stop bits indicating the end of the data packet. 
     Such printheads include data parsers which use a free-running clock and operate to capture incoming data bits as they are received by the printhead in order to detect the start pattern and thereby identify the beginning of a fire pulse group data packet. Upon detecting a start pattern, the data parser circuitry collects bits as they are received and directs them to the appropriate primitives. In some examples, to determine when the data packet is complete, the data parser circuitry counts the total number of bits received. When the correct number of bits for a data packet has been received, the data parser circuitry stops distributing bits and returns to monitoring incoming data to identify a start sequence for another data packet. 
     Among other functions, data parser circuitry typically includes several counters, such as to indicate a particular group of primitives to which the data is to be directed (e.g., a printhead may include multiple columns of primitives), and to count a total number bits which have been received, for example. Data parser circuitry consumes relatively large amounts of silicon area on a printhead die, thereby increasing the size and cost of the die. Additionally, data parser circuitry is inflexible and requires each fire pulse group data packet for a printhead to have a fixed length. Additionally, a free running clock can potentially introduce electromagnetic interference (EMI) issues to the die. 
     The present disclosure, as will be described in greater detail herein, provides a print component having an array of memory elements to serially receive a segment of data bits including configuration data and primitive data each time an intermittent clock signal is received on a clock pad, which eliminates data parser circuitry and a free running clock. Such an arrangement reduces silicon area requirements, eliminates EMI introduced by a free-running clock signal, and enables arrays of fluid actuators having different primitive sizes, such as different fluidic dies, to share a clock and fire signals, which reduces interconnect complexity. 
       FIG. 1  is a block and schematic diagram generally illustrating a print component  30 , according to one example of the present disclosure, including a plurality of data pads  32 , illustrated as data pads  32 - 1  to  32 -N, a clock pad  34  to receive an intermittent clock signal  35 , and a plurality of actuator groups  36 , illustrated as actuator groups  36 - 1  to  36 -N, with each actuator group  36  corresponding to a different one of the data pads  32 . In one example, each of the actuator groups  36  corresponds to a different fluid type. For instance, in one case, print component  30  comprises a printhead with each actuator group corresponding to a different type of ink (e.g., black, cyan, magenta, and yellow). In one example, each actuator group  36  of print component  30  is implemented in a different respective fluidic die where, in one case, each respective fluidic die corresponds to a different liquid type. 
     According to one example, each actuator group  36  includes a group of configuration functions  38 , illustrated as  38 - 1  to  38 -N, an array of fluid actuators  40 , illustrated as arrays  40 - 1  to  40 -N, and an array of memory elements  50 , illustrated as arrays  50 - 1  to  50 -N. In one case, each group of configuration functions  38  includes a number of configuration functions, illustrated as configuration functions CF( 1 ) to CF(m), for configuring an operational setup of the corresponding actuator group  36 . In examples, configuration functions CF( 1 ) to CF(m) may include functions such as an address driver, a fire pulse configuration function, and a sensor configuration function (e.g., thermal sensors), for instance. 
     In one example, each array of fluid actuators  40  includes a number of fluid actuators (FAs), with array  40 - 1  of actuator group  36 - 1  including fluid actuators FA( 1 ) to FA(x), array  40 - 2  of actuator group  36 - 2  including fluid actuators FA( 1 ) to FA(y), and array  40 -N of actuator group  40 -N including fluid actuators FA( 1 ) to FA(z). In one case, each array of fluid actuators  40  may have a same number of fluid actuators (x=y=z). In other cases, the arrays of fluid actuators  40  may have differing numbers of fluid actuators (x≠y≠z). 
     The array of memory elements  50  of each actuator group  36  comprises a number of memory elements  51 , with each array  50  having a first portion of memory elements  52 , illustrated as first portions  52 - 1  to  52 -N, corresponding to the respective group of configuration functions  38 , and a second portion of portion of memory elements  54 , illustrated as second portions  56 - 1  to  56 -N, corresponding to the respective array of fluid actuators  40 . In some cases, the array of memory elements  50  of each actuator group  36  may have a same number of memory elements  51 . In other cases, the array of memory elements  50  of different actuator groups  36  may have different numbers of memory elements  51 . 
     The array of memory elements  50  of each actuator group  36  is connected to the corresponding data pad  32  via a corresponding communication path  52 , with the arrays of memory elements  50 - 1  to  50 -N being respectively connected to data pads  32 - 1  to  32 -N by communication paths  52 - 1  to  52 - n.  In one example, as illustrated by the arrangement of  FIG. 1 , each array of memory elements  50  of each group of fluid actuators  36  is connected to and receives intermittent clock signal  35  via clock pad  34 . 
     In one example, each time intermittent clock  35  is present on clock pad  34  of print component  30 , the array of memory elements  50  of each actuator group  36  serially loads a data segment  33  comprising a series of data bits from the corresponding data pad  32 , illustrated as data segments  33 - 1  to  33 - n,  with the data bits loaded into the first portion of memory elements  52  and into the second portion of memory elements  54  respectively corresponding to the group of configuration functions  38  and to the array of fluid actuators  40 . In one example, each time intermittent clock signal  35  is present on clock pad  34 , the array of memory elements  50  of each actuator group  36  serially loads the series of data bits of a current data segment  33 , which replace the previously loaded data bits of the preceding data segment  33 . 
     In one example, as will be described in greater detail below (e.g., see  FIG. 3 ), the series of data bits of each data segment  33  include fire pulse groups similar to that described above. However, because print component  30 , loads each data segment  33  only when intermittent clock signal  35  is present on clock pad  34  (i.e., does not employ a free running clock), the fire pulse groups of data segments  33  do not include a start-bit sequence. Since data segments  33  do not include a start-bit sequence and are loaded into the array of memory elements  50  only when intermittent clock signal  35  is present on clock pad  34 , print component  30  and actuator groups  36 , in accordance with the present disclosure, do not include data parser circuitry, thereby saving circuit area and reducing costs. 
     Additionally, as described in greater detail below, using an intermittent clock signal  35  and an array of memory elements  50  to serially receive data enables print component  30  to support multiple arrays of fluid actuators  40  having differing numbers of fluid actuators and using fire pulse groups of varying lengths while operating on a same intermittent clock signal  35  and sharing a common fire signal (as will be described in greater detail below). Furthermore, employing an intermittent clock signal eliminates potential EMI problems associated with free-running clocks. 
       FIG. 2  is a block and schematic diagram generally illustrating a print component  30 , according to one example of the present disclosure. In one example, the actuator groups  36 - 1  to  36 - n  are implemented as fluidic dies  37 - 1  to  37 - n.  According to the example of  FIG. 2 , the fluid actuators (FA) of each of the arrays of fluid actuators  40 - 1  to  40 - n  of actuator groups  36 - 1  to  36 - n  are arranged to form a number of primitives, with the fluid actuators of array  40 - 1  of actuator group  36 - 1  arranged to form primitive P( 1 ) to P(x), the fluid actuators of array  40 - 2  of actuator group  36 - 2  arranged to form primitive P( 1 ) to P(y), and the fluid actuators of array  40 - n  of actuator group  36 - n  arranged to form primitive P( 1 ) to P(z), with each primitive including a number of fluid actuators FA( 1 ) to FA(p). In one case, each array of fluid actuators  40  may have a same number of primitives (x=y=z). In other cases, the arrays of fluid actuators  40  may have differing numbers of primitives (x≠y≠z). Although the primitives of each actuator group  36  is illustrated as having a same number of fluid actuators, p, in other examples, the number of fluid actuators in each primitive may vary between actuator groups  36 . 
     In one example, as illustrated, the array of memory elements  50  of each actuator group  37  comprises a series or chain of memory elements  51  implemented to function as a serial-to-parallel data converter, with first portion  54  of memory elements  51  corresponding to the group of configuration functions  38 , and second portion of memory elements  56  corresponding to the array of fluid actuators  40 , with each memory element  51  o the second portion  56  corresponding to a different one of the primitives P( 1 ) to P(x). In one example, the array of memory elements  50  of each actuator group  36  comprises a sequential logic circuit (e.g., flip-flop arrays, latch arrays, etc.). In one example, the sequential logic circuit is adapted to function as a serial-in, parallel-out shift register. 
     According to one example, the group of configuration functions  38  of each actuator group  36  includes an address driver  60 , illustrated at address drivers  60 - 1  to  60 - n,  which drives an address onto a corresponding address bus  62 , illustrated as address buses  62 - 1  to  62 - n,  based on address bits in corresponding memory elements  51  of first portion  54  of the array of memory elements  50 , with memory bus  62  communicating the driven address to fluid actuators FA( 1 ) to FA(p) of each of the corresponding primitives. In one example, print component  30  includes a fire pad  70  to receive a fire signal  72  which is communicated to each of the actuator groups  36  via a communication path  74 . 
     An example of the operation of print component  30  of  FIG. 2  is described below with reference to  FIGS. 3 and 4 .  FIG. 3  is a block and schematic diagram generally illustrating portions of a primitive arrangement for the primitives of actuator groups  36 - 1  to  36 - n  of  FIG. 2 . For illustrative purposes, the block and schematic diagram of  FIG. 2  is described with reference to primitive P( 1 ) of actuator group  36 - 1  of  FIG. 2 . 
     In example, each fluid actuator, illustrated as a thermal resistor in  FIG. 3 , is connectable between a power source, VPP, and a reference potential (e.g., ground) via a corresponding controllable switch, such as illustrated by FETs  80 . 
     According to one example, each primitive, including primitive P( 1 ), includes an AND-gate  82  receiving, at a first input, primitive data (e.g., actuator data) for primitive P( 1 ) stored in a local memory element  84 , where local memory element receives such primitive data from corresponding memory element  51  of the array of memory elements  50 - 1  of actuator group  36 - 1 . At a second input, AND-gate  82  receives fire signal  72  via communication path  70 . In one example, fire signal  72  is delayed by a delay element  86 , with each primitive having a different delay so that firing of fluid actuators is not simultaneous among primitives P( 1 ) to P(x). 
     In one example, each fluid actuator has a corresponding address decoder  88  receiving the address driven by address driver  60 - 1  on address bus  62 - 1 , and an AND-gate  90  for controlling a gate of FET  80 . AND-gate  90  receives the output of corresponding address decoder  88  at a first input, and the output of AND-gate  82  at a second input. It is noted that address decoder  88  and AND-gate  90  are repeated for each fluid actuator, while AND-gate  82 , memory element  84 , and delay element  86  are repeated for each primitive. 
       FIG. 4A  is a block diagram generally illustrating example data segments  33 - 1  to  33 - n  respectively received by print component  30  via data pads  32 - 1  to  32 - n.  As illustrated, each data segment  33  includes a fire pulse group  100  including a first portion of data bits  102  corresponding to the group of configuration functions  38  (sometimes referred to as configuration data), and a second portion of data bits  104  corresponding to the array of fluid actuators  40  (sometimes referred to as primitive data). For instance, with respect to data segment  33 - 1 , the data bits of the first portion of data bits  102 - 1  correspond to the group of configuration functions  38 - 1  and include address data bits for address driver  60 - 1 , and the data bits of the second portion of data bits  104 - 1  correspond to the array of fluid actuators  40 - 1 , with each data bit of second portion  104 - 1  corresponding to a different one of the primitives P( 1 ) to P(x). For each data segment  33 , the number of data bits of the fire pulse group  32  (i.e., the number of fire pulse bits) is equal to the sum of the number of bits of the first portion of data bits  102  (i.e., configuration data bits) and the number of bits of the second portion of data bits  104  (i.e., primitive data). 
     According to the example of  FIG. 4A , second portion 104 - 1  of fire pulse group  100 - 1  of data segment  33 - 1  is illustrated as having more primitive data bits than second portion  104 - 2  of fire pulse group  100 - 2  of data segment  33 - 2 , and second portion 104 - 2  of fire pulse group  100 - 2  of data segment  33 - 2  is illustrated as having more primitive data bits than second portion  104 - n  of fire pulse group  100 - n  of data segment  33 - n,  meaning that, with reference to  FIG. 2 , the array of fluidic actuators  40 - 1  of fluidic die  36 - 1  has a greater number of primitives than the array of fluidic actuators  40 - 2  of fluidic die  36 - 2 , while the array of fluidic actuators  40 - 2  of fluidic die  36 - 2  has a greater number of primitives than the array of fluidic actuators  40 - n  of fluidic die  36 - n  (i.e., x&gt;y&gt;z). As a result, fire pulse group  100 - 1  has more fire pulse group bits than fire pulse group  100 - 2 , and fire pulse group  100 - 2  has more fire pulse group bits than fire pulse group  100 - n,  meaning that data segment  33 - 1  is longer (i.e., has more data segment bits) than data segment  33 - 2 , and that data segment  33 - 2  is longer (i.e., has more data segment bits) than data segment  33 - n.    
     With reference to  FIG. 2 , upon intermittent clock signal  35  being received at clock pad  34  (e.g., upon receiving the first rising edge of intermittent clock signal  35 ), data segments  33 - 1  to  33 - n  are serially loaded into the memory elements  51  of their respective arrays of memory elements  50 - 1  to  50 - n  of actuator groups  36 - 1  to  36 - n.  However, when sharing a same intermittent clock signal  35 , as illustrated by the example implementation of  FIG. 2 , because of their different lengths, the number of cycles of intermittent clock signal  35  needed to load fire pulse group  100 - 1  of data segment  33 - 1  into array of memory elements  50 - 1  is greater than a number of clock cycles needed to load fire pulse groups  100 - 2  and  100 - n  of data segments  33 - 2  and  33 - n  into their respective arrays of memory elements  50 - 2  and  50 - n.  As a result, data bits of fire pulse groups  100 - 2  and  100 - n  of data segments  33 - 2  and  33 - n  will begin being respectively shifted out of arrays of memory elements  50 - 2  and  50 - n  before data bits of fire pulse group  100 - 1  of data segment  33 - 1  have finished being serially loaded into the array of memory elements  50 - 1 . Consequently, if not accounted for, incorrect data will be populating the memory elements of arrays  50 - 2  and  50 - n  upon completion of loading data segment  33 - 1  into array  50 - 1 . 
     With reference to  FIG. 4B , according to one example, when sharing an intermittent clock signal, such as clock signal  35 , in order to make each of the data segments  33 - 1  to  33 - n  equal in length (i.e., a same number of bits) so as to take a same number of clock cycles of intermittent clock signal  35  to load into their respective memory arrays  50 - 1  to  50 - n  , in addition to fire pulse groups  100 - 2  and  100 - n,  data segments  33 - 1  and  33 - n  each include a pre-pended segment of filler bits  110 - 1  and  110 - n.  According to one example, as illustrated, since data segment  33 - 1  is the longest data segment (i.e., has the most segment bits), the segment of filler bits  110 - 1  of data segment  33 - 1  contains no filler bits, while segments of filler bits  110 - 2  and  110 - n  each have a number of filler bits to respectively make data segments  33 - 2  and  33 - n  the same length as data segment  33 - 1  (with filler bit segment  33 - n  having more filler bits than filler bit segment  33 - 2 ). According to the example illustration of  FIG. 4B , in general, segments of filler bits  110  are added to each shorter data segment  33  of data segments  33 - 1  to  33 - n  so that all data segments  33 - 1  to  33 - n  have a length the same as the longest data segment  33  of data segments  33 - 1  to  33 - n.    
     By pre-pending filler bit segments  110 - 1  to  110 - n  to data segments  33 - 1  and  33 - n,  in a case where an intermittent clock signal is shared by actuator groups  36 - 1  to  36 - n,  when serially loading data segments  33 - 1  to  33 - n  into their respective arrays of memory elements  50 - 1  to  50 - n,  the last data bit of each data segments  33 - 1  to  33 - n  will be loaded on the same clock cycle so that each fire pulse group is properly loaded into their respective memory array  50 - 1  to  50 - n,  with the first and second portions of data bits  102  and  104  being respectively loaded into first and second portions  54  and  56  of the corresponding array of memory elements  50 . 
     Prepending filler bit segments  110  to at least data segments  33  having shorter lengths so that all data segments  33  have a same length enables a clock signal  35  to be shared by multiple arrays of fluidic actuators  36  even when such arrays of fluidic actuators  36  have differing numbers of fluid actuators (FAs), which reduces and simplifies circuitry, such as that of print component  30 . 
     In some examples, each of the data segments  33 - 1  to  33 - n  includes a filler bit segment  100  including a number of filler bits, where the number of filler bits in each filler bit segment  100 - 1  to  100 - n  is such that each of the data segments  33 - 1  to  33 - n  has a same length. In one example, each of the filler bits has either a logic “high” value (e.g. “1”) or a logic “low” value (“0”), where the filler bits of each filler bit segment  100  have a pattern of logic “low” and logic “high” values to mitigate electromagnetic effects on print component  30  as data segments  33 - 1  to  33 - n  are respectively serially loaded in memory arrays  50 - 1  to  50 - n.    
     Continuing with the illustrative example above, referring to  FIGS. 2-3 , in one case, upon the final data bit of each of the data segments  33 - 1  to  33 - n  being loaded into the respective array of memory elements  50 - 1  to  50 - n  (e.g., the last data bit each of the second portions  104 - 1  to  104 - n  of fire pulse groups  100 - 1  to  100 - n  being loaded into their respective memory element  51  corresponding to primitive P( 1 )), intermittent clock signal  35  is removed from clock pad  34  so that serial loading of data into memory arrays  50 - 1  to  50 - n  ceases. 
     According to one example, upon completion of loading of fire pulse groups  100 - 1  to  100 - n  into their respective memory arrays  50 - 1  to  50 - n,  a fire signal  72  (e.g., a fire pulse signal) is received on fire pad  70 . With reference to  FIGS. 2 and 3 , in one example, in response to receipt of fire pulse signal  72 , data stored in each memory element  51  of each array of memory elements  50 - 1  to  50 - n  are parallel shifted into a corresponding memory element in the corresponding array of fluid actuators  40 - 1  to  40 - n  or the group configuration functions  38 - 1  to  38 - n.  For example, in  FIG. 3 , in response to fire signal  72 , primitive data stored in memory element  51  is shifted to a corresponding memory element  84  in primitive P( 1 ). 
     In one example, after being parallel shifted out of the arrays of memory elements  50 - 1  to  50 - n,  the fire pulse group data is processed by the corresponding groups of configuration functions  38 - 1  to  38 - n  and primitives (P( 1 ) to P(x), P( 1 ) to P(y), and P( 1 ) to P(z)) to operate selected fluid actuators (FAs) to circulate fluid or eject fluid drops. For instance, with reference to  FIG. 3 , in one example, if the primitive data stored in memory element  84  has a logic high (e.g., “1”) and a fire pulse signal  72  is present on communication path  74 , the output of AND-gate  82  is set to a logic “high”. If the address driven on address bus  62 - 1  by address encoder  60 - 1  in response to the address bits received from the corresponding memory element of the second group of memory elements  54 - 1  represents address “0”, the output of Address Decoder “ 0 ”  88  is set to a logic “high”. With the output of AND-gate  82  and Address Decoder “ 0 ”  88  each set to a logic “high”, the output of AND-gate  90  is also set to a logic “high”, thereby turning “on” corresponding FET  80  to energize fluid actuator FA( 0 ) to displace fluid (e.g., eject a fluid drop). 
     In one example, upon the fire pulse group data being shifted out of the arrays of memory elements  50 - 1  to  50 - n  in response to fire signal  72 , intermittent clock signal  35  is again received via clock pad  34  and next data segments  33 - 1  to  33 - n  are serially loaded into the arrays of memory elements  50 - 1  to  50 - n.    
       FIG. 5  is a block and schematic diagram generally illustrating print component  30  of  FIG. 2 , where in addition to fluid actuators FA( 1 ) to FA(p), primitives P( 1 ) to P(x), P( 1 ) to P(y), and P( 1 ) to P(z) of actuator groups  40 - 1  to  40 - n  each include an array of memory elements, respectively illustrated as M( 1 ) to M(x), M( 1 ) to M(y), and M( 1 ) to M(z). In one example, as illustrated, each of the groups of configurations  38 - 1  to  38 - n  may include one or more memories, CM, each corresponding to a different one of the configuration functions. 
     In one example, print component  30  of  FIG. 5  further includes a mode pad  78  to receive a mode signal  79 . In one example, based on a state of mode signal  79 , upon fire signal  72  being raised on fire pad  70 , rather than data stored in the array of memory elements  50 - 1  to  50 - n  being shifted to the fluid actuators and configuration functions, the data is shifted to the primitive memory arrays of their respective primitives (e.g. M( 1 ) to M(x), M( 1 ) to M(y), and M( 1 ) to M(z)) and to the configuration memory, CM, of the respective group of configuration functions  38 - 1  to  38 - n.    
       FIG. 6  is a block and schematic diagram generally illustrating print component  30  of  FIG. 5 , where, in lieu of fluidic dies  37 - 1  to  37 - n  sharing a common intermittent clock signal  35 , each fluidic die  37 - 1  to  37 - n  receives its own corresponding intermittent clock signal, illustrated as clock signals  35 - 1  to  35 - n  via corresponding clock pads  34 - 1  to  34 - n.  With reference to  FIGS. 2-4 , since intermittent clock signals  35 - 1  to  35 - n  may be separately controlled (e.g., may start and/or stop at differing times), data segments  33 - 1  to  33 - n  do not need to be of a same length and, thus, may not include filler bit segments  110 . Referring to  FIG. 6 , upon completion of loading of fire pulse groups  100 - 1  to  100 - n  of data segments  33 - 1  to  33 - n  into the array of memory elements  50 - 1  to  50 - n  of the corresponding fluid die  37 - 1  to  37 - n,  fire signal  72  may be raised to initiate operations on the fire pulse group data (as described above). 
       FIG. 7  is a block diagram illustrating one example of a fluid ejection system  200 . Fluid ejection system  200  includes a fluid ejection assembly, such as printhead assembly  204 , and a fluid supply assembly, such as ink supply assembly  216 . In the illustrated example, fluid ejection system  200  also includes a service station assembly  208 , a carriage assembly  222 , a print media transport assembly  226 , and an electronic controller  230 . While the following description provides examples of systems and assemblies for fluid handling with regard to ink, the disclosed systems and assemblies are also applicable to the handling of fluids other than ink. 
     Printhead assembly  204  includes at least one printhead  212  which ejects drops of ink or fluid through a plurality of orifices or nozzles  214 , where printhead  212  may be implemented, in one example, as print component  30  with fluid actuators (FAs) of actuator groups  36 - 1  to  36 - n  implemented as nozzles  214 , as previously described herein by  FIG. 2 , for instance. In one example, the drops are directed toward a medium, such as print media  232 , so as to print onto print media  232 . In one example, print media  232  includes any type of suitable sheet material, such as paper, card stock, transparencies, Mylar, fabric, and the like. In another example, print media  232  includes media for three-dimensional (3D) printing, such as a powder bed, or media for bioprinting and/or drug discovery testing, such as a reservoir or container. In one example, nozzles  214  are arranged in at least one column or array such that properly sequenced ejection of ink from nozzles  214  causes characters, symbols, and/or other graphics or images to be printed upon print media  232  as printhead assembly  204  and print media  232  are moved relative to each other. 
     Ink supply assembly  216  supplies ink to printhead assembly  204  and includes a reservoir  218  for storing ink. As such, in one example, ink flows from reservoir  218  to printhead assembly  204 . In one example, printhead assembly  204  and ink supply assembly  216  are housed together in an inkjet or fluid-jet print cartridge or pen. In another example, ink supply assembly  216  is separate from printhead assembly  204  and supplies ink to printhead assembly  204  through an interface connection  220 , such as a supply tube and/or valve. 
     Carriage assembly  222  positions printhead assembly  204  relative to print media transport assembly  226 , and print media transport assembly  226  positions print media  232  relative to printhead assembly  204 . Thus, a print zone  234  is defined adjacent to nozzles  214  in an area between printhead assembly  204  and print media  232 . In one example, printhead assembly  204  is a scanning type printhead assembly such that carriage assembly  222  moves printhead assembly  204  relative to print media transport assembly  226 . In another example, printhead assembly  204  is a non-scanning type printhead assembly such that carriage assembly  222  fixes printhead assembly  204  at a prescribed position relative to print media transport assembly  226 . 
     Service station assembly  208  provides for spitting, wiping, capping, and/or priming of printhead assembly  204  to maintain the functionality of printhead assembly  204  and, more specifically, nozzles  214 . For example, service station assembly  208  may include a rubber blade or wiper which is periodically passed over printhead assembly  204  to wipe and clean nozzles  214  of excess ink. In addition, service station assembly  208  may include a cap that covers printhead assembly  204  to protect nozzles  214  from drying out during periods of non-use. In addition, service station assembly  208  may include a spittoon into which printhead assembly  204  ejects ink during spits to ensure that reservoir  218  maintains an appropriate level of pressure and fluidity, and to ensure that nozzles  214  do not clog or weep. Functions of service station assembly  208  may include relative motion between service station assembly  208  and printhead assembly  204 . 
     Electronic controller  230  communicates with printhead assembly  204  through a communication path  206 , service station assembly  208  through a communication path  210 , carriage assembly  222  through a communication path  224 , and print media transport assembly  226  through a communication path  228 . In one example, when printhead assembly  204  is mounted in carriage assembly  222 , electronic controller  230  and printhead assembly  204  may communicate via carriage assembly  222  through a communication path  202 . Electronic controller  230  may also communicate with ink supply assembly  216  such that, in one implementation, a new (or used) ink supply may be detected. 
     Electronic controller  230  receives data  236  from a host system, such as a computer, and may include memory for temporarily storing data  236 . Data  236  may be sent to fluid ejection system  200  along an electronic, infrared, optical or other information transfer path. Data  236  represent, for example, a document and/or file to be printed. As such, data  236  form a print job for fluid ejection system  200  and includes at least one print job command and/or command parameter. 
     In one example, electronic controller  230  provides control of printhead assembly  204  including timing control for ejection of ink drops from nozzles  214 . As such, electronic controller  230  defines a pattern of ejected ink drops which form characters, symbols, and/or other graphics or images on print media  232 . Timing control and, therefore, the pattern of ejected ink drops, is determined by the print job commands and/or command parameters. In one example, logic and drive circuitry forming a portion of electronic controller  230  is located on printhead assembly  204 . In another example, logic and drive circuitry forming a portion of electronic controller  230  is located off printhead assembly  204 . In another example, logic and drive circuitry forming a portion of electronic controller  230  is located off printhead assembly  204 . In one example, data segments  33 - 1  to  33 - n,  intermittent clock signal  35 , fire signal  72 , and mode signal  79  may be provided to print component  30  by electronic controller  230 , where electronic controller  230  may be remote from print component  30 . 
       FIG. 8  is a flow diagram illustrating a method  300  of operating a print component, such as print component  30  of  FIGS. 2-4 , in accordance with one example of the present disclosure. At  302 , method  300  includes receiving data segments on a number of data pads, such as receiving data segments  33 - 1  to  33 - n  on data pads  32 - 1  to  32 - n  as illustrated by  FIG. 2 , where each data segment comprises a number of segment bits, the number of segment bits including a fire pulse group comprising a number of fire pulse group bits, with the number of segment bits being at least equal to the number of fire pulse group bits, such as illustrated by  FIG. 4A  where each data segment  33 - 1  to  33 - n  respectively includes a fire pulse group  100 - 1  to  100 - n.    
     At  304 , method  300  includes receiving an intermittent clock signal on a clock pad, such as print component  30  of  FIG. 2  receiving an intermittent clock signal  35  on clock pad  34 . At  306 , method  300  includes arranging a number of fluid actuators to form a number of fluid actuator arrays, each array of fluid actuators having a corresponding array of memory elements corresponding to a different one of the data pads, such as actuator groups  36 - 1  to  36 - n  of  FIG. 2  respectively including an array of fluid actuators  40 - 1  to  40 - n,  with the arrays of fluid actuators  40 - 1  to  40 - n  respectively having a corresponding array of memory elements  50 - 1  to  50 - n,  with the array of memory elements  50 - 1  to  50 - n  respectively having corresponding data pads  32 - 1  to  32 - n.    
     At  308 , method  100  includes serially loading a data segment from the corresponding data pad into each array of memory elements each time the intermittent clock signal is present on the clock pad to store at least the fire pulse group bits, such as respectively loading data segments  33 - 1  to  33 - n  (as illustrated by  FIGS. 4A and 4B ) into arrays of memory elements  50 - 1  to  50 - 1  so as to respectively store at least fire pulse segments  100 - 1  to  100 - n.    
     Although specific examples have been illustrated and described herein, a variety of alternate and/or equivalent implementations may be substituted for the specific examples shown and described without departing from the scope of the present disclosure. This application is intended to cover any adaptations or variations of the specific examples discussed herein. Therefore, it is intended that this disclosure be limited only by the claims and the equivalents thereof.