upd63a Renesas Electronics Corporation., upd63a Datasheet - Page 23

• Manufacturer Part Number: upd63a
• Description: 4-bit Single-chip Microcontroller For Infrared Remote Control Transmission
• Manufacturer: Renesas Electronics Corporation.

5.2 Standby Mode Setup and Release
standby mode to be set, the status flag (F) is required to have been cleared (to 0).
operand of HALT instruction. If the standby mode is released, the status flag (F) is set (to 1).
mode is not set. If the release condition is not met at this time, the status flag is cleared (to 0). If the release condition
is met, the status flag remains set (to 1).
executed, the standby mode is not set. Here, also, the status flag (F) is set (to 1).
The standby mode is set with the HALT #b
The standby mode is released by the release condition specified with the RESET (RESET input; POC) or the
Even when the HALT instruction is executed in the state that the status flag (F) has been set (to 1), the standby
Even in the case when the release condition has been already met at the point that the HALT instruction is
Caution Depending on the status of the status flag (F), the HALT instruction may not be executed. Be
Example
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.
Reset
Release condition shown in Table 5-3
Table 5-2. Addresses Executed After Standby Mode Release
STTS
MOV
STTS
HALT
Release Condition
#03H
T, #0xxH
#05H
(During this time, be sure not to execute an instruction that may set the status flag.)
#05H
3
;To check the K
;To set the timer
;To clear the status flag
;To set HALT mode
b
2
b
1
b
0
B instruction for both STOP mode and HALT mode. For the
0 address
The address following the HALT instruction
I
pin status.
Address Executed After Release
PD63, 63A, 64
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