Abstract:
Peripheral functions of an integrated circuit device may be pooled and dynamically mapped to available external input-output connections of the integrated circuit device by using a set of configuration registers. To provide system robustness, the configuration registers may implement various levels of write protection, error correction and monitoring circuitry. One or more peripheral output functions may be mapped to one or more external output connections. Not more than one output function may be active at the same time on the same output connection. Outputs and inputs may be mapped to the same external input-output connection with or without the output being controllable for placement into an inactive state, e.g., high impedance or open collector. When the input is required to receive external data over the external input-output connection, the output may be placed into the inactive state.

Description:
RELATED PATENT APPLICATION 
       [0001]    This application claims priority to commonly owned U.S. Provisional Patent Application Ser. No. 60/803,835; filed Jun. 2, 2006; entitled “Dynamic Peripheral Pin Remapping” by Igor Wojewoda, Brian Boles, Steve Bradley and Gaurang Kavaiya; and is hereby incorporated by reference herein for all purposes. 
     
     TECHNICAL FIELD 
       [0002]    The present disclosure relates to coupling to peripheral functions in an integrated circuit device, and more specifically, to dynamically remapping specific input and output peripheral functions to designated external input-output connections of the integrated circuit device. The number of peripheral functions available may exceed that of the number of external input-output connections of the integrated circuit device. 
       BACKGROUND 
       [0003]    With decreasing process geometries in the fabrication of integrated circuit devices, it is now possible to include many more peripheral functions in a single mask set before an integrated circuit device becomes core limited. As a result, many integrated circuit devices have more peripheral features than can be activated at any one time, based upon the availability of external input-output connections, e.g., pins, ball bumps, surface mount leads, etc., on the integrated circuit package. In the past, several peripheral functions were hardwired onto a single external connection, which limited the overall integrated circuit device flexibility. An assumption had to be made as to which features would share the same external connection. 
       SUMMARY 
       [0004]    To solve this problem, an integrated circuit device, e.g., microprocessor, microcontroller, digital signal processor (DSP), programmable logic array (PLA), application specific integrated circuit (ASIC), etc., may include fully remappable peripheral functions. A set of peripheral input and output features not requiring special pad structures may be placed into a pool of remappable functions. Then using a set of registers, e.g., mapping registers, dynamic mapping of the desired peripheral functions to the available external input-output connections of the integrated circuit device may be easily achieved by a user. 
         [0005]    It is contemplated and within the scope of this disclosure that the mapping registers may be lockable. Optionally, once the mapping registers are locked from programming they may not be prevented from being programmed again. The mapping registers may comprise redundant logic, and if a data mismatch occurs in the redundant logic then the integrated circuit device may reset. 
         [0006]    For peripheral outputs, the user may map a specific peripheral function to an external output connection. This prevents multiple output functions from being active at the same time on the same output. An output and at least one input may be mapped to the same external input-output connection as the output driver may be controllable as active or inactive, e.g., high impedance or open collector state, when the at least one input common to the output is to receive data from an external source connected to the external input-output connection. Also, some outputs may be monitored by respective inputs without having to become inactive. Some bidirectional data buses may be for example but not limited to a serial bidirectional data bus, one wire bidirectional data bus, SPI bus, I 2 C bus, etc. 
         [0007]    For peripheral inputs, the user may map a specific external input connection to a peripheral function. This allows the user to map a single external input connection to as many peripheral functions (e.g., edge interrupt and SPI clock, etc.) as desired. These I/O mapping configurations may be stored in a plurality of mapping registers that may be programmed by a user. To provide system robustness, the mapping registers may implement various levels of write protection, error correction and monitoring circuitry. These additional security features may also be configured by the user depending on the system requirements. 
         [0008]    As more peripheral functions are included in an integrated circuit device, the overall device functions become limited by the number of external input-output connections rather than the availability of the peripheral functions. Having remappable peripheral functions to external input, output and/or input-output connections allows a user to tailor and maximize the integrated circuit device features that may be available (e.g., peripheral functions) specifically to a desired application. It is contemplated and within the scope of this disclosure that more peripheral functions may be fabricated into the integrated circuit device than there are input, output and/or input-output connections available on the integrated circuit device. This allows a single peripheral feature rich integrated circuit mask set that has the capabilities for much broader market applications. 
         [0009]    According to a specific example embodiment of this disclosure, an integrated circuit device having dynamic peripheral function to external input-output connection remapping may comprise: a plurality of peripheral functions; a plurality of mapping registers; a plurality of drivers; a plurality of receivers; a plurality of input-output external connections, wherein each one of the plurality of input-output external connections is coupled to an input of a respective one of the plurality of receivers and an output of a respective one of the plurality of drivers; a plurality of first multiplexers, each of the plurality of first multiplexers has inputs coupled to the respective ones of the plurality of receivers, an output coupled to the respective one of the plurality of peripheral functions and a control input coupled to a respective one of the plurality of mapping registers, wherein the respective one of the plurality of mapping registers controls which one of the plurality of receivers is coupled to the respective one of the plurality of peripheral functions; a plurality of second multiplexers, each of the plurality of second multiplexers has inputs coupled to the respective ones of the plurality of peripheral functions, an output coupled to a data input of the respective one of the plurality of drivers and a control input coupled to the respective one of the plurality of mapping registers, wherein the respective one of the plurality of mapping registers controls which one of the plurality of drivers is coupled to the respective one of the plurality of peripheral functions; and a plurality of third multiplexers, each of the plurality of third multiplexers has inputs coupled to the respective ones of the plurality of peripheral functions, an output coupled to a control input of the respective one of the plurality of drivers and a control input coupled to the respective one of the plurality of mapping registers, wherein the respective one of the plurality of peripheral functions controls characteristics of the respective one of the plurality of drivers. 
         [0010]    According to another specific example embodiment of this disclosure, an integrated circuit device having dynamic peripheral function to external output connection remapping may comprise: a plurality of peripheral functions; a plurality of mapping registers; a plurality of drivers; a plurality of output external connections, wherein each one of the plurality of output external connections is coupled to an output of a respective one of the plurality of drivers; a plurality of data multiplexers, each of the plurality of data multiplexers has inputs coupled to the respective ones of the plurality of peripheral functions, an output coupled to a data input of the respective one of the plurality of drivers and a control input coupled to the respective one of the plurality of mapping registers, wherein the respective one of the plurality of mapping registers controls which one of the plurality of drivers is coupled to the respective one of the plurality of peripheral functions; and a plurality of control multiplexers, each of the plurality of control multiplexers has inputs coupled to the respective ones of the plurality of peripheral functions, an output coupled to a control input of the respective one of the plurality of drivers and a control input coupled to the respective one of the plurality of mapping registers, wherein the respective one of the plurality of peripheral functions controls characteristics of the respective one of the plurality of drivers. 
         [0011]    According to yet another specific example embodiment of this disclosure, an integrated circuit device having dynamic peripheral function to external input connection remapping may comprise: a plurality of peripheral functions; a plurality of mapping registers; a plurality of receivers; a plurality of input external connections, wherein each one of the plurality of input external connections is coupled to an input of a respective one of the plurality of receivers; and a plurality of multiplexers, each of the plurality of multiplexers has inputs coupled to the respective ones of the plurality of receivers, an output coupled to the respective one of the plurality of peripheral functions and a control input coupled to a respective one of the plurality of mapping registers, wherein the respective one of the plurality of mapping registers controls which one of the plurality of receivers is coupled to the respective one of the plurality of peripheral functions. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    A more complete understanding of the present disclosure thereof may be acquired by referring to the following description taken in conjunction with the accompanying drawings wherein: 
           [0013]      FIG. 1  illustrates a schematic block diagram of input-output (I/Os) circuits in an integrated circuit device having dynamic peripheral remapping, according to a specific example embodiment of this disclosure; 
           [0014]      FIG. 2  illustrates a schematic block diagram of output circuits in an integrated circuit device having dynamic peripheral remapping, according to another specific example embodiment of this disclosure; and 
           [0015]      FIG. 3  illustrates a schematic block diagram of input circuits in an integrated circuit device having dynamic peripheral remapping, according to yet another specific example embodiment of this disclosure. 
       
    
    
       [0016]    While the present disclosure is susceptible to various modifications and alternative forms, specific example embodiments thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the description herein of specific example embodiments is not intended to limit the disclosure to the particular forms disclosed herein, but on the contrary, this disclosure is to cover all modifications and equivalents as defined by the appended claims. 
       DETAILED DESCRIPTION 
       [0017]    Referring now to the drawings, the details of specific example embodiments are schematically illustrated. Like elements in the drawings will be represented by like numbers, and similar elements will be represented by like numbers with a different lower case letter suffix. 
         [0018]    Referring to  FIG. 1 , depicted is a schematic block diagram of input-output (I/Os) circuits in an integrated circuit device having dynamic peripheral remapping, according to a specific example embodiment of this disclosure. An integrated circuit device  102 , e.g., microprocessor, microcontroller, digital signal processor (DSP), programmable logic array (PLA), application specific integrated circuit (ASIC), etc., may be enclosed in an integrated circuit package (not shown) having a plurality of external input-output (I/O) connections  104 , e.g., pins, solder ball bumps, surface mount leads, etc. Each of these plurality of external I/O connections  104  may be coupled to a respective one of a plurality of drivers  106  and a respective one of a plurality of receivers  108  through an integrated circuit device bond pad (not shown) used for connection of the integrated circuit die to the external I/O connections  104  with, for example, wire bonding and lead frame connections. In addition each of the integrated circuit bond pads (coupled to the each of the plurality of external I/O connections  104 ) may have electrostatic discharge (ESD) protection  119  coupled thereto. 
         [0019]    Each of the plurality of receivers  108  may be coupled to respective inputs  124   a - 124   m  of a plurality of multiplexers  110  (only one multiplexer  110  is shown for clarity). An output  134  from each of the plurality of multiplexers  110  may be coupled to an input of a respective one of a plurality of peripheral functions  116 , e.g., clock input, timer reset, counter input, etc. Each of the plurality of multiplexers  110  may be controlled, e.g., an input selected for coupling to the output of the multiplexer  110  by a control signal  132  from a respective one of a plurality of mapping registers  118 . For example, at least one peripheral input may be coupled to one or more of the plurality of receivers  108 , and/or one or more peripheral inputs may be coupled to more than one of the plurality of receivers  108 . 
         [0020]    Each of the plurality of multiplexers  110  may have m inputs, e.g., matching the number of receivers  108 , and an output. The control signal  132  may be sent on a binary parallel or serial bus and have a sufficient number of bits for control of the m inputs. It is contemplated and with the scope of this disclosure that instead of using the plurality of multiplexers  110  for coupling each of the plurality of receivers  108  to respective ones of the plurality of peripheral inputs, that an input switching matrix circuit (not shown) may be used to couple the outputs from any one or more of the plurality of receivers  108  to any one or more of the plurality of peripheral inputs. The input switching matrix (not shown) may be used to couple any one or more of the plurality of receivers  108  to any one or more of the plurality of peripheral inputs by using the control signals  132  from the plurality of mapping registers  118 . 
         [0021]    Each of the plurality of drivers  106  may be coupled to respective outputs  120  of a plurality of multiplexers  112  (only one multiplexer  112  is shown for clarity). Each of a plurality of inputs  128  of the plurality of multiplexers  112  may be coupled to an output of a respective one of a plurality of peripheral functions  116 , e.g., clock output, timer reset out, counter output, etc. Each of the plurality of multiplexers  112  may be controlled, e.g., an input selected for coupling to the output of the multiplexer  112  by a control signal  130  from a respective one of a plurality of mapping registers  118 . In addition, control signals  122  to each of the plurality of drivers  106  may be used to control operation and/or characteristics of the respective driver  106  in an active or inactive state, e.g., open collector, active pull-up, active pull-down, or tri-state having active logic high and active logic low with a high impedance third state. Selection of the pull-up or pull-down resistance value, slew rate, drive capabilities, etc., for the drivers  106  may also be configured. These configurations may be performed by firmware in the integrated circuit device  102  and/or external program software having access to and configuration permission for the integrated circuit device  102 . 
         [0022]    Each of the control signals  122  coupled to a respective one of the plurality of drivers  106  may be coupled to a control signal output from a respective one of the plurality of peripheral functions  116  through respective ones of a plurality of multiplexers  114 . Each of the plurality of multiplexers  112  and  114  may have n inputs, e.g., matching the number of the plurality of peripheral functions  116  data and control outputs  128  and  126 , respectively. The control signals  130  to the plurality of multiplexers  112  and  114  may be sent on binary parallel or serial buses and have a sufficient number of bits for control of the n inputs. 
         [0023]    It is contemplated and with the scope of this disclosure that instead of using the plurality of multiplexers  112  and  114  for coupling each of the plurality of drivers  106  to respective outputs of the plurality of peripherals  116 , that a switching matrix circuit (not shown) may be used to couple the inputs of the plurality of drivers  106  to respective outputs of the plurality of peripheral functions  116 . For example, one or more drivers  106  may be coupled to an output of a peripheral functions  116 , however, not more than one output of a peripheral function  116  may be active at a time. This prevents multiple output functions from becoming active at the same time, but allows multiple drivers  106  to have the same data information available for a plurality of external circuits (load fanout sharing) and/or increased drive capabilities for a particular load. 
         [0024]    Referring to  FIG. 2 , depicted is a schematic block diagram of output circuits in an integrated circuit device having dynamic peripheral remapping, according to another specific example embodiment of this disclosure. An integrated circuit device  102 , e.g., microprocessor, microcontroller, digital signal processor (DSP), programmable logic array (PLA), application specific integrated circuit (ASIC), etc., may be enclosed in an integrated circuit package (not shown) having a plurality of external output connections  204 , e.g., pins, ball bumps, surface mount leads, etc. Each of these plurality of external out connections  204  may be coupled to a respective one of a plurality of drivers  206  through an integrated circuit device bond pad (not shown) used for connection of the integrated circuit die to the external output connections  204  with, for example, wire bonding and lead frame connections. In addition each of the integrated circuit bond pads (coupled to the each of the plurality of external output connections  204 ) may have electrostatic discharge (ESD) protection  219  coupled thereto. 
         [0025]    Each of the plurality of drivers  206   a - 206   p  may be coupled to respective outputs  220   a - 220   p  of a plurality of multiplexers  212   a - 212   p.  Each of a plurality of inputs  128  of the plurality of multiplexers  212   a - 212   p  may be coupled to an output of a respective one of a plurality of peripheral functions  116 , e.g., clock output, timer reset out, counter output, etc. Each of the plurality of multiplexers  212   a - 212   p  may be controlled, e.g., an input selected for coupling to the output of the multiplexers  212   a - 212   p  by control signals  130   a - 130   p  from a respective one of a plurality of mapping registers  118 . In addition, control signals  222   a - 222   p  to respective ones of the plurality of drivers  206   a - 206   p  may be used to control operation thereof in an active or inactive state, e.g., open collector, active pull-up, active pull-down, or tri-state having active logic high and active logic low with a high impedance third state. Selection of the pull-up or pull-down resistance value, slew rate, drive capabilities, etc., for the drivers  206  may also be configured. These configurations may be performed by firmware in the integrated circuit device  102  and/or external program software having access to and configuration permission for the integrated circuit device  102 . 
         [0026]    Each of the control signals  222   a - 222   p  coupled to a respective one of the plurality of drivers  206   a - 206   p,  respectively, may be coupled to control signal outputs from respective ones of the plurality of peripheral functions  116  through respective ones of a plurality of multiplexers  214   a - 214   p.  Each of the plurality of multiplexers  212  and  214  may have n inputs, e.g., matching the number of the plurality of peripheral functions  116  data and control outputs  128  and  126 , respectively. The control signals  130   a - 130   p  to the plurality of multiplexers  212   a - 212   p  and  214   a - 214   p  may be sent on binary parallel or serial buses and have a sufficient number of bits for control of the n inputs. 
         [0027]    It is contemplated and with the scope of this disclosure that instead of using the plurality of multiplexers  212   a - 212   p  and  214   a - 214   p  for coupling each of the plurality of drivers  206   a - 206   p  to respective outputs of the plurality of peripheral functions  116 , that a switching matrix circuit (not shown) may be used to couple the inputs of the plurality of drivers  206   a - 206   p  to respective outputs of the plurality of peripheral functions  116 . For example, one or more drivers  206  may be coupled to an output of a peripheral function  116 , however, not more than one output of a peripheral function  116  may be couple to any one or more drivers  206 . This prevents multiple output functions from becoming active at the same time, but allows multiple drivers  206  to have the same data information available for a plurality of external circuits (load fanout sharing) and/or increased drive capabilities for a particular load. 
         [0028]    Referring to  FIG. 3 , depicted is a schematic block diagram of input circuits in an integrated circuit device having dynamic peripheral remapping, according to yet another specific example embodiment of this disclosure. An integrated circuit device  102 , e.g., microprocessor, microcontroller, digital signal processor (DSP), programmable logic array (PLA), application specific integrated circuit (ASIC), etc., may be enclosed in an integrated circuit package (not shown) having a plurality of external input connections  304 , e.g., pins, ball bumps, surface mount leads, etc. Each of these plurality of external input connections  304  may be coupled to a respective one of a plurality of receivers  308  through an integrated circuit device bond pad (not shown) used for connection of the integrated circuit die to the external input connections  304  with, for example, wire bonding and lead frame connections. In addition each of the integrated circuit bond pads (coupled to the each of the plurality of external input connections  304 ) may have electrostatic discharge (ESD) protection  319  coupled thereto. 
         [0029]    Each of the plurality of receivers  308   a - 308   m  may be coupled to respective inputs  324   a - 324   m  of a plurality of multiplexers  310   a - 310   s.  Outputs  134   a - 134   s  from the plurality of multiplexers  310   a - 310   s,  respectively, may be coupled to respective inputs of a plurality of peripheral functions  116 , e.g., clock input, timer reset, counter input, etc. Each of the plurality of multiplexers  310   a - 310   s  may be controlled, e.g., an input selected for coupling to the output of the plurality of multiplexers  310   a - 310   s  by control signals  132   a - 132   s  from respective ones of a plurality of mapping registers  118 . Each of the plurality of multiplexers  310   a - 310   s  may have m inputs, e.g., matching the number of receivers  308   a - 308   m,  and an output. The control signals  132   a - 132   s  may be sent on binary parallel or serial buses and have a sufficient number of bits for control of the m inputs. 
         [0030]    It is contemplated and with the scope of this disclosure that instead of using the plurality of multiplexers  310   a - 310   s  for coupling each of the plurality of receivers  308   a - 308   m  to respective inputs of the plurality of peripherals  116 , that a switching matrix circuit (not shown) may be used to couple the outputs from any one or more of the plurality of receivers  308   a - 308   m  to any one or more inputs of the plurality of peripheral functions  116  by using the control signals  132   a - 132   s  from the plurality of mapping registers  118 . For example, at least one input of the plurality of peripheral functions  116  may be coupled to one or more of the plurality of receivers  308   a - 308   m,  and/or one or more peripheral inputs may be coupled to more than one of the plurality of receivers  308   a - 308   m.    
         [0031]    The I/O mapping configurations stored in the plurality of mapping registers  118  may be programmed by a user. The plurality of mapping registers  118  may be locked, may be writable only when unlocked, may be implemented in redundant logic with a mismatch causing a device reset, and/or the register lock may be configured to be one-way only, e.g., once locked it cannot be unlocked again. The mapping registers may be non-volatile memory. 
         [0032]    The integrated circuit device  102  may comprise more peripherals  116  than there are external input connections  304 , external output connections  204 , and/or external I/O connections  104 . This allows a user greater flexibility in applying the integrated circuit device  102  to a desired application. It also allows the integrated circuit device  102  to be used for applications in a much broader market, thus increasing demand and lowering costs for a mass produced peripheral feature rich product having configuration flexibility for both the types of peripherals selected and the external connection mapping of the selected peripherals. 
         [0033]    While embodiments of this disclosure have been depicted, described, and are defined by reference to example embodiments of the disclosure, such references do not imply a limitation on the disclosure, and no such limitation is to be inferred. The subject matter disclosed is capable of considerable modification, alteration, and equivalents in form and function, as will occur to those ordinarily skilled in the pertinent art and having the benefit of this disclosure. The depicted and described embodiments of this disclosure are examples only, and are not exhaustive of the scope of the disclosure.