Mode processing circuit

A mode processing circuit for a multi-operation mode electronic apparatus including a mode stack having a plurality of stages in which an input command signal is stored as an operation mode of the multi-operation mode electronic apparatus, wherein the operation mode inputted to the mode stack is sequentially stored and optimized and the optimized operation mode is read out from the mode stack in the sequential order and then executed after the transition of the operation mode is ended.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a mode processing circuit for a multiple 
operation mode electronic apparatus such as a video tape recorder, a tape 
deck, a video disc player, a compact disc player and so on. 
2. Description of the Prior Art 
Various operation modes, such as a playback mode, a rewind mode and the 
like are available in a known video tape recorder (hereinafter simply 
referred to as a VTR). To change these operation modes, it is necessary to 
switch the VTR or to move its brake and pinch roller into and out of 
engagement. 
If a plunger is used to switch the mechanism, the change of the operation 
mode can be made substantially in a moment. The employment of the plunger, 
however, causes a large current to flow upon its actuation. Also, in the 
normal operation mode, a current must flow continuously, requiring a large 
power supply circuit which consumes a large amount of power. 
It is therefore proposed to employ a motor instead of the plunger. When a 
motor is used together with a gear mechanism, atthough it is small in 
size, the necessary driving power to switch the mechanism is generated. 
Further, the employment of the motor can reduce the power consumption and 
allow the power supply circuit to be small in size. However, when a motor 
is used to switch the mechanism, the transition (switching) of its mode 
takes a lot of time. For example, it takes about 2 seconds for the VTR to 
change from the stop mode (STOP) to the playback mode (PB); it takes about 
1.5 seconds for the VTR to change from the playback mode (PB) to the stop 
mode (STOP); and it takes about 1.8 seconds for the VTR to change from the 
stop mode (STOP) to the recording mode (REC). 
Accordingly, when a user intends to press a second operation key after a 
first operation key has been depressed, the user must not press the second 
operation key until the VTR finishes changing to the mode commanded by the 
first key. 
This is very inconvenient for the user, so it is proposed to stack input 
commands issued by pressing the operation keys. 
Let it now be assumed that as, for example, illustrated in FIG. 1, the VTR 
is placed in the stop mode before time point t.sub.1 and that a recording 
key is pressed at time point t.sub.1. Then, the mode of the VTR 
(mechanism) begins to change from the stop mode to the recording mode at 
time point t.sub.1. 
If a stop key, for example, is pressed at time point t.sub.2 during this 
transition period, this stop key is valid for the recording mode which is 
the mode after the mode is changed, so that the command instructing not 
the recording mode but the stop mode after the mode transition, is stacked 
in the mode stack. 
When the mode transition of the VTR is ended at time point t.sub.3, the VTR 
is placed in the recording mode (REC). At that time, the stop mode command 
stacked in the mode stack at time point t.sub.2 is read out and the 
processing of this command is executed. 
Accordingly, the VTR begins the transfer to the stop mode at time point 
t.sub.3 and is placed in the stop mode at time point t.sub.4. Even though 
a pause key is pressed at time point t.sub.5 in the stop mode, the pause 
mode (PAUSE) is useless for the stop mode. Hence, the command issued by 
pressing the pause key is not executed. 
As described above, according to this mode stack system, it becomes 
posiible to remove the cumbersome requirement that the user must not press 
the next operation key until the mode transition of the VTR is ended (even 
if the next key is pressed, this will be neglected). However, the above 
mentioned mode stack system has the following defect. 
If the stop key is pressed at time point t.sub.2 and the pause key is then 
pressed at time point t.sub.a as, for example, shown in FIG. 2, since this 
pause key is valid for the recording mode, which is the mode after the 
mode transition (if the pause key is depressed in the recording mode, the 
VTR is placed in the recording pause mode (REC PAUSE)), and the mode 
stacked in the mode stack is changed again from the stop mode to the 
recording pause mode. 
Accordingly, the mode of the VTR is moved to the recording pause mode at 
time point t.sub.3 and the VTR is placed in the recording pause mode at 
time point t.sub.4. 
Although the stop key and the pause key are pressed in the same sequential 
order as that of FIG. 1, the VTR is placed in an operation mode different 
from that in FIG. 1 in this case because of the timing of the depression 
of the pause key vis-a-vis the actual mode shifting of the VTR. 
In other words, if a plurality of valid operation keys are depressed during 
the mode transition period, the mode stacked in the mode stack is renewed 
to the mode suggested by the operation key that was last pressed by the 
user and the modes commanded by the previously-pressed operation keys are 
all neglected. Accordingly, the operation mode of the VTR becomes 
different depending on the timing at which the user presses the operation 
keys (depending on whether the VTR mode was in the process of being 
changed or was already changed when the keys were pressed). 
To overcome the above mentioned shortcomings, an improved mode stack system 
is proposed, in which the mode stack is arranged to have a plurality of 
stages to sequentially stack the input modes and to execute the modes 
sequentially. 
This mode stack system having a plurality of stages, however, must remove 
useless or invalid modes stacked in the mode stack by optimizing the mode 
stacked. This makes a program of a mode control microcomputer complicated 
and takes a lot of time for such removal. This defect becomes serious 
particularly when 8-bit mode data is processed by a CPU (central 
processing unit) which is capable of providing only a 4-bit comparing 
command. Further, an area for the mode stack must be provided in a RAM. 
OBJECTS AND SUMMARY OF THE INVENTION 
Accordingly, it is a general object of this invention to provide an 
improved mode processing circuit for a multi-operation mode electronic 
apparatus, such as a VTR. 
A more specific object of this invention is to provide an improved mode 
processing circuit for a multi-operation mode electronic apparatus, by 
which an operation mode can be changed in the shortest period of time to a 
desired operation mode when an operation key is pressed. 
Another object of this invention is to provide a mode processing circuit 
for a multi-operation mode electronic apparatus in which the apparent time 
required by the mode transition can be removed. 
A further object of this invention is to provide a mode processing circuit 
for a multi-operation mode electronic apparatus in which the VTR can be 
placed in the same final mode by pressing the corresponding operation key 
at any time. 
Yet a further object of this invention is to provide a mode processing 
circuit for a multi-operation mode electronic apparatus in which the 
optimizing operation becomes unnecessary, so that the program of the mode 
controller is simplified, taking less time. 
Still a further object of this invention is to provide a mode processing 
circuit for a multi-operation mode electronic apparatus which does not 
require a stack area. 
Still a further object of this invention is to provide a mode processing 
circuit for use with a multi-operation mode electronic apparatus, such as 
a video tape recorder, a tape deck, a video disc player, a compact disc 
player and so on. 
According to one aspect of the present invention, there is provided a mode 
processing circuit for a multi-operation mode electronic apparatus 
comprising: 
a mode stack for receiving and storing operation mode commands for said 
multi-operation mode electronic apparatus; 
means for sequentially storing said operation mode commands received by 
said mode stack and for optimizing the same; and 
means for deriving said optimized operation mode commands from said mode 
stack in the sequential order and then executing the same after the 
transition of said operation mode is ended. 
According to another aspect of the present invention, there is provided a 
mode processing circuit for a multi-operation mode electronic apparatus 
comprising: 
a transition vector look-up table memory means for indicating an operation 
mode to which the operation mode of said multi-operation mode electronic 
apparatus should be shifted; 
means for determining a final mode of said multi-operation mode electronic 
apparatus in accordance with an input command; 
means for determining a new operation mode to which the operation mode of 
said multi-operation mode electronic apparatus is to be shifted next from 
said final mode and a mode to which the operation mode of said 
multi-operation mode electronic apparatus was shifted with reference to 
said transition vector look-up table memory means; and 
means for changing the operation mode of said multi-operation mode 
electronic apparatus to said operation mode thus determined and then 
placing said multi-operation mode electronic apparatus in said final mode. 
These and other objects, features and advantages of the present invention 
will become apparent from the following detailed description of the 
preferred embodiments that are to be read in conjunction with the 
accompanying drawings, throughout which like reference numerals identify 
like elements and parts.

DESCRIPTION OF THE PREFERRED EMBODIMENTS 
Now, the present invention will hereinafter be described in detail with 
reference to the drawings. 
FIG. 3 illustrates hardware relating to the mode transition operation of 
the VTR according to the present invention. 
Referring to FIG. 3, there is shown a mechanism (VTR) control section 1 
which includes a loading motor 11 for loading or unloading a tape on or 
from the VTR, a control motor 12 for controlling the mode of the VTR and a 
servo circuit 13 for controlling a drum and a capstan of the VTR. 
A mode controller 2 is formed of a microcomputer whose output is supplied 
to the control section 1 to place the VTR in each operation mode. At the 
same time, a signal indicative of the state (mode) of the VTR is supplied 
from the control section 1 to the mode controller 2. 
Key input means 3 is provided with a plurality of operation keys (not 
shown). A receiving circuit 4 is adapted to receive a signal inputted by 
the operation key of a remote controller (not shown) when the VTR is 
operated by the remote controller. The key input signals from the key 
input means 3 and the receiving circuit 4 are both supplied to the mode 
controller 2. Mode indicating means 5 visually indicates to the user, e.g. 
by an LCD display, the mode in which the VTR is placed, on the basis of 
the output signal from the mode controller 2. 
The mode stack is provided within a RAM (random access memory) of the 
microcomputer which forms the mode controller 2. 
When the operation key of the key inputting means 3 or the operation key of 
the remote controller (not shown) is pressed, its command is processed by 
the mode controller 2 and the processed result or data is supplied to the 
control section 1, so that the control section 1 is operated so as to 
place the VTR in a predetermined operation mode. At the same time, the 
corresponding mode of the VTR is visually indicated by the mode indicating 
means 5. 
FIG. 4 illustrates, by way of example, how the VTR mode and data stacked in 
the mode stack are changed with the command inputted when the operation 
key is pressed at a certain time point. 
In the description below, "present mode" and "final mode" are respectively 
defined as follows: the "present mode" indicates the mode of the VTR at 
that certain time point and also indicates, during the mode transition 
period of the VTR, the net mode to which the VTR is to be placed; and the 
"final mode" indicates the mode stored last in the mode controller 2 at 
that certain time point. The final mode becomes the same as the present 
mode when no mode data is stacked in the mode stack at all. Validity of 
the operation key pressed is judged depending upon whether the operation 
key pressed is valid for the final mode or not. The mode indicating means 
5 visually indicates the final mode. 
In the illustrated example of FIG. 4, since the VTR is placed in the stop 
mode before time point t.sub.1, the present mode is the stop mode. At the 
same time, no mode is stacked in the mode stack and the final mode and the 
visual indication thereof are the stop mode. 
When the recording key is pressed at time point t.sub.1, this recording 
mode is valid for the final mode (stop mode), so that "REC" (recording 
mode) is stacked in the first stage of the mode stack. However, since the 
VTR has not yet started changing its operation mode, the VTR immediately 
starts changing its mode from the stop mode to the recording mode, and 
"REC" is indicated by the mode indicating means 5. Further, the "REC" mode 
command stacked in the mode stack is removed. 
If the stop key is pressed at time point t.sub.2 while the VTR is changing 
its mode, the stop mode is valid for the final mode (recording mode), so 
that "STOP" (stop mode) is stacked in the first stage of the mode stack 
and the final mode and the visual indication thereof are made the stop 
mode. However, the VTR itself is changing its operation mode into the 
recording mode (present mode) which was dsignated by the key input at time 
point t.sub.1. 
When the pause key is pressed at time point t.sub.3, while the VTR is in 
the mode transition period, the pause mode is invalid for the final mode 
(stop mode), so that this key input is neglected, leaving the mode stack, 
the final mode and the visual indication unchanged. 
When the rewind key is pressed at time point t.sub.4, while the VTR is in 
the mode transition period, the rewind mode is valid for the final mode 
(stop mode), so that "REW" (rewind mode) is stacked in the second stage of 
the mode stack and the final mode and the visual indication thereof are 
made the rewind mode. However, the VTR itself is still in the process of 
changing its operation mode into the recording mode (present mode) which 
was designated by the key input at time point t.sub.1. 
When the stop key is pressed at time point t.sub.5 while the VTR is in the 
mode transition period, the stop mode is valid for the final mode (rewind 
mode), so that "STOP" (stop mode) is stacked in the third stage of the 
mode stack. At that time, since the same "STOP" (stop mode) is also 
stacked in the first stage of the mode stack, "STOP" and "REW" stacked 
respectively in the first and second stages of the mode stack are removed 
and "STOP" stacked in the third stage of the mode stack is transferred to 
the first stage of the mode stack. This processing is an example of what 
may be called "optimization". In that case, the final mode and the visual 
indication thereof are made stop mode. 
When the playback key is pressed at time point t.sub.6, while the VTR is in 
the mode transition period, the playback mode is valid for the final mode 
(stop mode), so that "PB" (playback mode) is stacked in the second stage 
of the mode stack and the final mode and the visual indication thereof are 
made the playback mode. 
When the fast forward key is pressed continuously from the time point 
t.sub.7 while the VTR is in the mode transition period, the fast forward 
mode is valid for the final mode (playback mode). At the same time, upon 
the playback mode, the fast forward key is pressed in the cue mode, so 
that "CUE" (cue mode) is stacked in the third stage of the mode stack and 
the final mode and the visual indication thereof are made the cue mode. 
At time point t.sub.8, when the VTR finishes changing its operation mode 
into the recording mode designated by the key input at time point t.sub.1, 
the mode stack is checked. In this case, since "STOP" is stacked in the 
first stage of the mode stack, this "STOP" is set to the present mode and 
the VTR therefore starts changing its operation mode to the stop mode at 
time point t.sub.9 (.congruent.t.sub.8). When it is confirmed that the 
operation mode of the VTR is to be changed to the stop mode, "PB" stacked 
in the second stage of the mode stack is transferred to the first stage 
thereof and "CUE" stacked in the third stage of the mode stack is 
transferred to the second stage thereof, making the third stage of the 
mode stack empty. 
When the VTR has finished changing its operation mode to the stop mode at 
time point t.sub.10, the mode stack is checked. In this case, since "PB" 
is stacked in the first stage of the mode stack, this "PB" is set to the 
present mode, so that the VTR starts changing its operation mode to the 
playback mode at time point t.sub.11 (.congruent.t.sub.10). After it is 
confirmed that the operation mode of the VTR was changed to the playback 
mode, "CUE" stacked in the second stage of the mode stack is transferred 
to the first stage thereof, thus making the second stage of the mode stack 
empty. 
When the VTR has finished changing its mode to the playback mode at time 
point t.sub.12, the mode stack is checked. Since "CUE" is stacked in the 
first stage of the mode stack, this "CUE" is set to the present mode, so 
that the VTR starts changing its operation mode into to the cue mode at 
time point t.sub.13 (.congruent.t.sub.12). After it is confirmed that the 
operation mode of the VTR was changed to the cue mode, the mode stack is 
made empty. In this way, the VTR is placed in the cue mode after time 
point t.sub.13. 
While the operation mode of the VTR and mode data stacked in the mode stack 
are changed as described above, this will be also explained with reference 
to a general algorithm which is represented in the form of a flow chart in 
FIG. 5. 
This algorithm is exemplified in the flow chart (FIG. 5) of the program 
that the microcomputer forming the mode controller 2 (FIG. 3) executes. 
The presence or absence of the command (key input) inputted by the 
operation key is checked, as represented at decisional step 21 in FIG. 5. 
If the command exists, the processing of the microcomputer (mode 
controller 2) goes from step 21 to decisional step 22. Then, it is 
checked, as represented at decisional step 22, whether or not the key 
input of which the presence was confirmed at step 21 is valid for the 
final mode. The validity of the key input relative to the final mode is 
checked on the basis of a mode transition look-up table which forms, for 
example, FIG. 6. Such a look-up table can be store within a ROM (read only 
memory) which forms the mode controller 2 (FIG. 3). This mode transition 
look-up table of FIG. 6 reads as follows. 
If the recording key ("REC") is pressed when the final mode is, for 
example, the playback ("PB") mode, it is judged that this recording key is 
invalid for the final mode, however, if the pause key is pressed instead, 
it is judged that this pause key is valid for the final mode and the final 
mode is renewed to "PB PAUSE" (playback pause mode). 
If the key input is judged to be valid as represented at decisional step 
22, the processing of the microcomputer goes from step 22 to step 23. As 
represented at step 23, the final mode and the visual indication thereof 
are renewed at time point t.sub.4 shown, for example, in FIG. 4 and in 
FIG. 7 (reference letters A to E throughout FIGS. 7 to 11 respectively 
designate operation modes) in accordance with the mode transition look-up 
table of FIG. 6. Then, the operation mode renewed is stacked in the mode 
stack. 
The processing of the microcomputer goes from step 23 to the next 
decisional step 31. It is checked, as represented at decisional step 31, 
whether or not a mode which is the same as the renewed final mode is 
stacked in the mode stack. If not, the processing of the microcomputer 
goes from step 31 to decisional step 33. 
If on the other hand the same mode is stacked in the mode stack, as for 
example shown at time point t.sub.5 in FIG. 4 and as illustrated in FIG. 
8, the processing of the microcomputer goes from step 31 to the next step 
32. As represented at step 32, the modes, beginning from the mode (B mode 
in the second stage) which is the same as the final mode renewed in the 
mode stack up to the mode (D mode) just one stage before the final stage 
of the mode stack, are removed as unnecessary modes and the final mode 
renewed is shifted to the prior stage of the mode stack. This processing 
forms a part of "optimization". 
Then, the processing of the microcomputer goes from step 32 (or step 31) to 
decisional step 33 where it is checked whether or not a mode which can be 
changed directly to the final mode is stacked in the mode stack, thereby 
omitting unnecessary intermediate modes. If not, the processing of the 
microcomputer goes from step 33 to decisional step 41. If on the other 
hand such a mode is stacked in the mode stack, the processing of the 
microcomputer goes from step 33 to step 34. At step 34, as shown in FIG. 
9, the modes between the mode (B mode), which can be changed to the final 
mode, and the final mode (E mode) are removed and the final mode (E mode) 
is shifted to the stage of the mode stack subsequent to the mode which can 
be changed to the final mode (B mode). This processing also forms a part 
of "optimization". 
The processing of the microcomputer goes from step 34 (or step 33) to the 
next decisional step 41. Also, if the absence of a key input is 
determined, as represented at decisional step 21, or if the key input is 
invalid for the final mode, as represented at decisional step 22, the 
processing of the microcomputer goes directly from step 21 or 22 to the 
decisional step 41. 
At decisional step 41 the microcomputer checks whether the VTR is now 
changing its operation mode or has finished its mode changing. If the VTR 
is changing its operation mode, the processing of the microcomputer goes 
from step 41 to the next decisional step 42 where the microcomputer checks 
whether a mode which is the same as the present mode exists in the mode 
stack or not. If not, the processing of the microcomputer goes from step 
42 to decisional step 44. If the same mode exists in the mode stack as 
represented at decisional step 42, as shown, for example, in FIG. 10, the 
processing of the microcomputer goes from step 42 to step 43. As 
represented at step 43, the modes from the mode (A mode) of the first 
stage to the mode (C mode) which is the same as the mode which is under 
transition, are removed and the next mode (D mode) is shifted forward (to 
the first stage of the mode stack). This processing also forms a part of 
"optimization". 
Subsequently, the processing of the microcomputer goes from step 43 (or 
step 42) to the next decisional step 44 where it is checked whether or not 
there is a mode in the mode stack to which the present mode of the VTR in 
its transition period can be directly shifted, as for example, shown in 
FIG. 11 (mode A can be shifted to mode D). If not, the processing of the 
microcomputer returns from step 44 to the decisional step 21. If such a 
mode exists in the mode stack the processing goes from step 44 to step 45. 
At step 45 the modes from the mode in the first stage to the mode (C mode) 
which is located just before the transferrable mode are removed and the 
succeeding mode (D mode) is shifted forward in the mode stack, so that 
"optimization" is carried out. Then, the processing of the microcomputer 
goes back to step 21. 
If it is determined, as represented at decisional step 41, that the VTR has 
already finished changing its operation mode, the processing of the 
microcomputer goes from step 41 to decisional step 51. It is then checked, 
as represented at decisional step 51, whether or not any mode command 
remains stacked in the mode stack. If no mode is stacked in the mode 
stack, the processing of the microcomputer goes back from step 51 to step 
21. If, on the other hand, one or more modes remain stacked in the mode 
stack, the processing of the microcomputer goes from step 51 to step 52 
where the present mode of the VTR begins to change into the mode of the 
first stage in the mode stack. If it is confirmed that the change of the 
operation mode of the VTR is started, the mode of the first stage in the 
mode stack is removed and the next mode is shifted forward. Subsequently, 
the processing of the microcomputer goes back from step 52 to step 21. 
Therefore, according to the above described processing routine, the 
operation mode of the VTR is changed as, for example, shown in FIG. 4. 
Alternatively, the presence or absence of the key input can be checked by 
executing the condition determining command instead of using the mode 
transition look-up table, as represented at decisional step 21. 
Furthermore, the present invention is not limited to a VTR (mechanism) but 
can similarly be applied to various other kinds of multi-operation mode 
electronic apparatus, such as, a tape deck, a video disc player or a 
compact disc (CD) player and the like which require a lot of time to 
change their operation modes. 
Another embodiment of the mode processing circuit according to the present 
invention will now be described. This embodiment is similar to that shown 
in FIG. 3 but in this embodiment, a mode transition look-up table and a 
mode transition vector look-up table shown, for example, in FIGS. 12 and 
13 are provided within a ROM (read only memory) which forms the mode 
controller 2 (FIG. 3). 
When the operation key of the inputting means 3 or the operation key of the 
remote controller (not shown) is pressed, the input data or command is 
similarly supplied to the mode controller 2, in which it is processed. The 
processed result or data therefrom is then supplied to the control section 
1, whereby the control section 1 is so operated as to place, for example, 
the VTR in the predetermined operation mode and the operation mode in 
which the VTR is just placed is visually indicated by the mode indicating 
means 5 similar to the first embodiment. 
FIG. 14 illustrates an example in which the operation mode of the VTR is 
changed with the command inputted by the operation key using this second 
embodiment. 
In the description below, "present mode" and "final mode" are respectively 
defined as follows: the "present mode" indicates the mode in which the VTR 
is now placed at a certain time point and also indicates the next 
operation mode of the VTR during the mode transition period; and the 
"final mode" indicates the mode stored last in the mode controller 2 at 
that time point. The validity of the operation key pressed is determined 
depending upon whether the operation key pressed is valid for the final 
mode or not. The mode indicating means 5 visually indicates the final 
mode. 
The areas in which the present mode and the final mode are stored are 
formed within the RAM of the microcomputer forming the mode controller 2. 
In this embodiment, since the VTR is paaced in the stop mode before time 
point t.sub.1, the present mode at time point t.sub.1 is the stop mode. 
Also, the final mode and the visual indication thereof are the stop mode. 
When the reproducing key is pressed at time point t.sub.1 in FIG. 14, the 
mode transition table in FIG. 12 is looked up by the microcomputer. This 
mode transition look-up table in FIG. 12 indicates whether or not, when 
the operation key is depressed, the key input is valid for the final mode 
at that time point or if the key input is valid for the final mode, to 
which mode the mode is to be transferred. Since the final mode is the stop 
mode at time point t.sub.1 and the key input is the playback mode, it will 
be clear from the mode transition look-up table of FIG. 12 that the 
operation mode of the VTR should be "PB" (playback mode). 
Accordingly, the final mode and the visual indication thereof are made the 
playback mode from time point t.sub.1. Further, the VTR (mechanism) starts 
changing its operation mode from the stop mode into the playback mode and 
the present mode is made the playback mode. 
When the stop key is pressed at time point t.sub.2 while the VTR is in the 
mode transition period as shown in FIG. 14, the mode transition look-up 
table of FIG. 12 is looked up. Since this mode transition look-up table of 
FIG. 12 indicates that the mode should be shifted to the stop mode, the 
final mode and the visual indication thereof are made the stop mode. 
However, during this period, the VTR itself continues changing its 
operation mode to the playback mode (present mode) which was designated by 
the key input at time point t.sub.1. 
Further, when the recording key is pressed at time point t.sub.3 during 
this mode transition period of the VTR, the same mode transition table 
(FIG. 12) is looked up. This mode transition look-up table of FIG. 12 
indicates that the mode should be shifted to the recording mode. Thus, the 
final mode and the visual indication thereof are made the recording mode. 
However, during this period, the VTR itself continues changing its 
operation mode into the playback mode which was designated by the key 
input at time point t.sub.1. 
When at time point t.sub.4 the operation mode of the VTR has finally 
changed into the playback mode, the mode transition vector table forming 
FIG. 13 is looked up. This mode transition vector look-up table of FIG. 13 
indicates whether or not at that time the VTR should further change its 
operation mode and the mode into which the VTR should change its operation 
mode. At that time (at time point t.sub.4 in FIG. 14), since the present 
mode is the playback mode and the final mode is the recording mode, the 
mode transition vector look-up table of FIG. 13 indicates that the mode of 
the VTR should be "PB PAUSE" (playback pause mode). Accordingly, the VTR 
starts changing its operation mode to the playback pause mode from time 
point t.sub.4 and the present mode is changed into the playback pause 
mode, too. 
When the mode transition to the playback pause mode is ended at time point 
t.sub.5, the same mode transition vector table of FIG. 13 is looked up. At 
time point t.sub.5 in FIG. 14, since the present mode is "PB pause" 
(playback pause mode) and the final mode is "REC" (recording mode), it 
will be clear from the mode transition vector look-up table of FIG. 13 
that the mode should be "REC PAUSE" (recording pause mode) next. 
Accordingly, the VTR starts changing its operation mode into the recording 
pause mode at time point t.sub.5 and the present mode is made the 
recording pause mode, too. 
When the mode transition of the VTR to the recording pause mode is ended at 
time point t.sub.6 in FIG. 14, the mode transition vector table of FIG. 13 
is looked up again. At time point t.sub.6 in FIG. 14, since the present 
mode is the recording pause mode and the final mode is the recording mode, 
the mode transition vector look-up table of FIG. 13 indicates that the 
next mode should be the recording mode. Accordingly, the VTR starts 
changing its operation mode into the recording mode at time point t.sub.6, 
and the present mode is made the recording mode, too. 
When the mode transition to the recording mode is ended at time point 
t.sub.7, the mode transition vector table of FIG. 13 is looked up. At time 
point t.sub.7 in FIG. 14, since the present mode and the final mode are 
both the recording mode and equal to each other, the operation mode of the 
VTR is not change any more. Accordingly, the VTR remains placed in the 
recording mode after time point t.sub.7. 
While the operation mode of the VTR is changed as described above, this 
mode changing operation of the VTR will be similarly explained by a 
general algorithm which is represented in a flow chart forming FIG. 15. 
In other words, this algorithm forms the flow chart (FIG. 15) of a program 
that the microcomputer forming the mode controller 2 (FIG. 3) executes. 
Firstly, the presence or absence of a command inputted by pressing an 
operation key is checked as represented at decisional step 121. If the 
presence of the command is confirmed at step 121, the processing of the 
microcomputer (mode controller 2) goes from step 121 to the next 
decisional step 122. It is checked as represented at decisional step 122 
by the mode transition look-up table of FIG. 12 whether or not the key 
input (command) whose existence was checked at step 121 is valid for the 
final mode. 
If it is judged as represented at decisional step 122 that the key input is 
valid for the final mode, the processing of the microcomputer goes from 
step 122 to step 123, in which the final mode and the mode visual 
indication thereof are renewed in accordance with the mode transition 
look-up table of FIG. 12, as represented at time point t.sub.1 in FIG. 14. 
Then, the processing of the microcomputer goes from step 123 to the next 
decisional step 131. 
Also, if the absence of the key input is confirmed as represented at 
decisional step 121 or it is judged as represented at decisional step 122 
that the key input is invalid for the final mode, the processing of the 
microcomputer goes directly from steps 121 and 122 to the next decisional 
step 131. 
It is checked, as represented at decisional step 131, whether the mode of 
the VTR is still shifting or it has already finished. If the mode of the 
VTR is shifting, the processing of the microcomputer goes back from step 
131 to step 121. 
Accordingly, the steps 121 to 123 and the step 131 are repeatedly executed 
during the period from the time point t.sub.1 to the time point t.sub.4. 
If on the other hand it is judged, as represented at decisional step 131, 
that the mode transition of the VTR is already ended, the processing of 
the microcomputer goes from step 131 to the next decisional step 132. 
There, it is checked whether or not the present mode is equal to the final 
mode. If they are not equal to each other, the processing of the 
microcomputer goes from step 132 to step 133. As represented at step 133, 
the operation mode to which the mode of the VTR should be newly shifted is 
determined with reference to the mode transition vector look-up table of 
FIG. 13, whereby the present mode is renewed to the new operation mode 
determined. 
Then, the processing of the microcomputer goes from step 133 to step 134. 
The VTR starts changing its operation mode to the present mode, which was 
renewed as represented at step 133, as represented at step 134, and the 
processing of the microcomputer goes back from step 134 to step 121. 
Consequently, the steps 131 to 134 are executed at time points t.sub.4, 
t.sub.5 and t.sub.6 in the mode transition diagram forming FIG. 14, 
respectively. 
If it is judged, as represented at decisional step 132, that the present 
mode and the final mode are equal to each other, the processing of the 
microcomputer goes back from step 132 to step 121. 
Accordingly, this processing of the microcomputer is executed at time point 
t.sub.7. 
According to the processing routine in FIG. 15 as described above, the 
operation mode of the VTR is changed as, for example, shown in the mode 
transition diagram of FIG. 14. 
It will be appreciated that the presence or absence of the command inputted 
by the operation key can be checked by using a condition judging command 
instead of using the above mentioned mode transition look-up table, as 
represented at decisional step 122 in FIG. 15. 
The present invention is not limited to a VTR as mentioned above but can be 
applied to various kinds of multi-operation mode electronic apparatus such 
as a tape deck, a video disc player, a CD (compact disc) player and the 
like which take a lot of time to change their operation modes. 
According to the present invention, since the transition mode to which the 
mode of the multi-operation mode electronic apparatus should be 
transferred is stacked in the mode stack and is optimized, the operation 
mode of the multi-operation mode electronic apparatus can be changed to 
the desired operation mode in the shortest period of time at the time 
point at which the operation key is pressed. 
If the key input is valid, the reception of the key input and the visual 
indication of the operation mode can be immediately executed and the 
transition of the operation mode of the multi-operation mode electronic 
apparatus can be carried out in the shortest period of time, so that the 
user never feels that the multi-operation mode electronic apparatus is 
taking a great deal of time to change its operation mode and thus, the 
apparent time required by such a mode transition can be removed. Further, 
the operation mode can be changed to the same final operation mode by 
pressing the operation key at any timing. 
Furthermore, according to the present invention, as set forth above, even 
if any number of operation keys are pressed, since the operation mode to 
which the mode of the multi-operation mode electronic apparatus should be 
shifted can be made optimum in accordance with the mode transition vector 
look-up table, the operation mode can be changed to the desired mode in 
the minimum number of mode transitions at the time point at which the 
operation key is pressed. 
In addition, since the optimization is not required, the processing program 
to be executed by the mode controller 2 can be simplified and the 
execution of the program does not take a lot of time. Also, the mode stack 
area becomes unnecessary. 
The above description is given for the preferred embodiments of the 
invention but it will be apparent that many modifications and variations 
could be effected by one skilled in the art without departing from the 
spirit or scope of the novel concepts of the invention, so that the scope 
of the invention should be determined by the appended claims only.