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23
μ
PD6133, 6134
Data Sheet U10454EJ6V0DS00
5.2 Standby Mode Setup and Cancelation
The standby mode is set with the HALT #b
3
b
2
b
1
b
0
B instruction for both STOP mode and HALT mode. For the
standby mode to be set, the status flag (F) is required to have been cleared (to 0).
The standby mode is canceled by the cancelation condition specified with the RESET (RESET input; POC) or
the operand of HALT instruction. If the standby mode is canceled, the status flag (F) is set (to 1).
Even when the HALT instruction is executed in the state that the status flag (F) has been set (to 1), the standby
mode is not set. If the cancelation condition is not met at this time, the status flag is cleared (to 0). If the cancelation
condition is met, the status flag remains set (to 1).
Even in the case when the cancelation condition has been already met at the point that the HALT instruction
is executed, the standby mode is not set. Here, also, the status flag (F) is set (to 1).
Caution Depending on the status of the status flag (F), the HALT instruction may not be executed. Be
careful about this. For example, when setting HALT mode after checking the key status with
the STTS instruction, the system does not enter HALT mode as long as the status flag (F)
remains set (to 1) thus sometimes performing an unintended operation. In this case, the
intended operation can be realized by executing the STTS instruction immediately after timer
setting to clear (to 0) the status flag.
Example
STTS
#03H
;To check the K
I
pin status.
MOV
STTS
T, #0xxH
#05H
(During this time, be sure not to execute an instruction that may set the status flag.)
#05H
;To set HALT mode
;To set the timer
;To clear the status flag
HALT
Table 5-2. Addresses Executed After Standby Mode Release
Cancelation Condition
Address Executed After Cancelation
Reset
0 address
Cancelation condition shown in Table 5-3
The address following the HALT instruction
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