SM5953 Datasheet, PDF (38/43 Pages) SyncMOS Technologies,Inc – Six interrupt sources with two priority levels

SM5953
8-Bit Micro-controller
15KB with ISP Flash
& 256B RAM embedded
11. Power Management Unit
Power management unit serves two power management modes, Idle and Power Down, for the users to do power
saving function.
Mnemonic: PCON
7
6
5
SMOD
-
-
Address: 87h
4
3
2
1
0
Reset
-
GF1 GF0
PD
IDLE 00h
GF1: General-purpose flag bit.
GF0: General-purpose flag bit.
PD: Power Down mode control bit. Setting this bit turning on the PD Mode.
PD bit is always read as 0
IDLE: Idle mode control bit. Setting this bit turning on the Idle Mode.
Idle bit is always read as 0
11.1 Idle mode
An instruction that sets PCON.0 causes that to be the last instruction executed before going into the idle mode, the
internal clock is gated off to the CPU but not to the interrupt, timer and serial port functions.
There are two ways to terminate the idle. Activation of any enabled interrupt will cause PCON.0 to be cleared by
hardware, terminating the idle mode. The interrupt will be serviced, and following RETI, the next instruction to be
executed will be the one following the instruction that put the device into idle. Another way to wake-up from idle is
to pull RESET high to generate internal hardware reset.
11.2 Power Down mode
An instruction that sets PCON.1 cause that to be the last instruction executed before going into the Power-Down
mode. In the power-down mode, the on-chip oscillator is stopped. The contents of on-chip RAM and SFRs are
maintained. Be carefully to keep RESET pin active for at least 10ms in order for a stable clock.
The power-down mode can be woken-up by RESET pin. When it is woken-up by RESET, the program will execute
from the address 0000H.
Mode
Idle
Idle
Power-Down
Power-Down
Pin Status in IDLE Mode and Power-Down Mode
Program Memory
ALE
PSEN
Port0
Port1
Internal
1
1
Data
Data
External
1
1
Float
Data
Internal
0
0
Data
Data
External
0
0
Float
Data
Port2
Data
Address
Data
Data
Port3
Data
Data
Data
Data
Specifications subject to change without notice contact your sales representatives for the most recent information.
ISSFD-M074
Ver D SM5953 04/16/2015
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