MSM80C154S/83C154S/85C154HVS

4.9.3.2Cancellation of CPU power down mode (IDLE, PD) by interrupt request signal and restart from next address of stop address

To cancel idle mode (IDLE) or soft power down mode (PD) by interrupt request signal and then resume execution from the next address after the stop address, “1” is set in bit 5 (RPD) of the power control register. When “1” is set in this bit, the circuit connections shown in Figure 4-80 are made, and the CPU power down mode is cancelled when the interrupt flag has been set to “1”, even if the entire contents of the interrupt enable register (IE 0A8H) have been put into interrupt disable status.

All six interrupt sources can be used to cancel idle mode (IDLE). If an interrupt source is generated and “1” is set in one of the interrupt flags in TCON, T2CON, or SCON, clock signals are passed to the CPU control stage, and execution is resumed from the next address after the stop address.

Soft power down mode (PD) can be cancelled by four different interrupt sources - external interrupts 0 and 1 , and timer interrupts 0 and 1. The external interrupt flag is set by “0” level being applied to either the INT0 or INT1 pin. And timer/counters 0 and 1 are used in external clock mode. When one of the interrupt flags in TCON is set to “1”, XTAL1·2 operation is commenced, and the program is executed from the next address after the stop address. Note, however, that the interrupt flags are reset by software. The cancellation time charts are shown in Figures 4-81 thru 4-84.

IE0 [TCON.1]

TF0 [TCON.5]

IE1 [TCON.3]

TF1 [TCON.7]

RI/TI [SCON.0, 1]

EXF2/TF2 [T2CON.6, 7]

IDLE, PD MODE

RESTART

*MODE SET

 

SMOD

HPD

RPD

GF1

GF0

PD

IDL

 

 

 

 

 

 

 

 

 

Bit

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

Set

 

 

 

 

 

*

*

 

 

 

 

 

 

 

 

 

Figure 4-80 Equivalent circuit for power down mode cancellation and restart by interrupt source signal

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Sonic Alert msm83c154s, msm80154s, msm85c154hvs user manual 182, IDLE, PD Mode Restart Mode SET Smod HPD RPD GF1 GF0