upd64a Renesas Electronics Corporation., upd64a Datasheet - Page 23

• Manufacturer Part Number: upd64a
• Description: 4-bit Single-chip Microcontroller For Infrared Remote Control Transmission
• Manufacturer: Renesas Electronics Corporation.

5.2 Standby Mode Setting and Release
standby mode to be set, the status flag (F) is required to have been cleared (0).
instruction. If the standby mode is released, the status flag (F) is set (1).
is not set. If the release condition is not met at this time, the status flag is cleared (0). If the release condition is
met, the status flag remains set (1).
executed, the standby mode is not set. Here, also, the status flag (F) is set (1).
The standby mode is set with the HALT #b
The standby mode is released by the release condition specified with the reset (POC) or the operand of the HALT
Even when the HALT instruction is executed in a state in which the status flag (F) is set (1), the standby mode
Even in the case when the release condition has already been met at the point that the HALT instruction is
Caution Note that depending on the status of the status flag (F), the HALT instruction may not be
Example
executed. 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
(1), sometimes resulting in an unintended operation. In this case, the intended operation can
be realized by executing the STTS instruction immediately after setting the timer to clear (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
Data Sheet U14380EJ3V0DS00
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
PD64A, 65
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