Philips CEM2100/00, Service Manual

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Page 19
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5CL8
Figure 2-7 Level-sensitive Release Mode
Note 1: Even if the
STOP
pin input is low after warm-up start, the STOP mode is not restarted.
Note 2: In this case of changing to the level-sensitive mode from the edge-sensitive mode, the release
mode is not switched until a rising edge of the
STOP
pin input is detected.
(2) Edge-sensitive release mode (RELM = “0”)
In this mode, STOP mode is released by a rising edge of the
STOP
pin input. This is used in appli-
cations where a relatively short program is executed repeatedly at periodic intervals. This periodic
signal (for example, a clock from a low-power consumption oscillator) is input to the
STOP
pin. In
the edge-sensitive release mode, STOP mode is started even when the
STOP
pin input is high level.
Do not use any STOP3 to STOP0 pin input for releasing STOP mode in edge-sensitive release mode.
Figure 2-8 Edge-sensitive Release Mode
Example 2 :Starting STOP mode from NORMAL mode with an INT5 interrupt.
PINT5: TEST (P2PRD). 0 ; To reject noise, STOP mode does not start if
JRS F, SINT5 port P20 is at high
LD (SYSCR1), 01010000B ; Sets up the level-sensitive release mode.
DI ; IMF
←
0
SET (SYSCR1). 7 ; Starts STOP mode
SINT5: RETI
Example :Starting STOP mode from NORMAL mode
DI ; IMF
←
0
LD (SYSCR1), 10010000B ; Starts after specified to the edge-sensitive release mode
V
IH
NORMAL
operation
Warm up
STOP
operation
Confirm by program that the
STOP pin input is low and start
STOP mode.
Always released if the STOP
pin input is high.
STOP pin
XOUT pin
STOP mode is released by the hardware.
NORMAL
operation
NORMAL
operation
NORMAL
operation
V
IH
STOP mode is released by the hardware at the rising
edge of STOP pin input.
Warm up
STOP mode started
by the program.
STOP
operation
STOP
operation
STOP pin
XOUT pin