M68HC16 Z SERIES
SYSTEM INTEGRATION MODULE
USER’S MANUAL
5-23
Figure 5-7 SIML LPSTOP Flowchart
SET UP INTERRUPT
TO WAKE UP MCU
FROM LPSTOP
LEAVE IMBCLK
1
ON IN LPSTOP?
NO
YES
SET STOP BITS FOR
MODULES THAT WILL
NOT BE ACTIVE IN
LPSTOP
SET STCPU
2
= 1
f
imbclk
= f
sys
IN LPSTOP
SET STCPU
2
= 0
f
imbclk
= 0 Hz
IN LPSTOP
USING
EXTERNAL CLOCK?
NO
YES
USE SYSTEM CLOCK
AS SIMCLK IN LPSTOP?
NO
YES
SET STSIM = 1
f
simclk
3
= f
sys
IN LPSTOP
WANT CLKOUT
ON IN LPSTOP?
NO
YES
NO
YES
WANT CLKOUT
ON IN LPSTOP?
SET STSIM = 0
f
simclk
3
= f
ref
IN LPSTOP
SET STEXT = 1
f
clkout
4
= f
sys
f
eclk
=
÷
f
sys
IN LPSTOP
SET STEXT = 0
f
clkout
4
= 0 Hz
f
eclk
=
÷
0 Hz
IN LPSTOP
SET STEXT = 1
f
clkout
4
= f
ref
f
eclk
=
÷
0 Hz
IN LPSTOP
SET STEXT = 0
f
clkout
4
= 0 Hz
f
eclk
=
÷
0 Hz
IN LPSTOP
ENTER LPSTOP
NOTES:
1. IMBCLK IS THE CLOCK USED BY THE CPU16L, SIML, ADC, MCCI, AND THE GPT.
2. WHEN STCPU = 1, THE CPU16L IS SHUT DOWN IN LPSTOP. ALL OTHER MODULES WILL REMAIN ACTIVE UNLESS
THE STOP BITS IN THEIR MODULE CONFIGURATION REGISTERS ARE SET PRIOR TO ENTERING LPSTOP.
3. THE SIMCLK IS USED BY THE PIT, IRQ, AND INPUT BLOCKS OF THE SIML.
4. CLKOUT CONTROL DURING LPSTOP IS OVERRIDDEN BY THE EXOFF BIT IN SIMCR. IF EXOFF = 1, THE CLKOUT
PIN IS ALWAYS IN A HIGH-IMPEDANCE STATE AND STEXT HAS NO EFFECT IN LPSTOP. IF EXOFF = 0, CLKOUT
IS CONTROLLED BY STEXT IN LPSTOP. WHEN STCPU = 1, THE CPU16L IS DISABLED IN LPSTOP, BUT ALL OTHER
MODULES REMAIN ACTIVE OR STOPPED ACCORDING TO THE SETTING.
SIML LPSTOP FLOWCHART
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Freescale Semiconductor, Inc.
For More Information On This Product,
Go to: www.freescale.com
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