PD62A_15 Datasheet, PDF (24/64 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLER FOR INFRARED REMOTE CONTROL TRANSMISSION

µPD62A
5. STANDBY FUNCTION
5.1 Outline of Standby Function
To save current consumption, two types of standby modes, HALT mode and STOP mode, are made available.
In STOP mode, the system clock stops oscillation. At this time, the XIN and XOUT pins are fixed at a low level.
In HALT mode, CPU operation halts, while the system clock continues oscillating. When in HALT mode, the
timer (including REM output and LED output) operates.
In either STOP mode or HALT mode, the statuses of the data memory, accumulator, and port register, etc.
immediately before the standby mode was set are retained. Therefore, make sure to set the port status for the system
so that the current consumption of the whole system is suppressed before the standby mode is set.
Table 5-1. Statuses During Standby Mode
Setting instruction
Clock oscillation circuit
CPU
Data memory
Operation
Accumulator
statuses
Flag
F
CY
Port register
Timer
STOP Mode
HALT Mode
HALT instruction
Oscillation stopped
Oscillation continues
• Operation halted
• Immediately preceding status retained
• Immediately preceding status retained
• 0 (When 1, the flag is not placed in the standby mode.)
• Immediately preceding status retained
• Immediately preceding status retained
• Operation halted
• Operable
(The count value is reset to “0”)
Cautions 1. Write the NOP instruction as the first instruction after STOP mode is canceled.
2. When standby mode is canceled, the status flag (F) is set (to 1).
3. If, at the point the standby mode has been set, its cancelation condition is met, then the
system is not placed in the standby mode. However, the status flag (F) is set (1).
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Data Sheet U14474EJ2V0DS00