mc68hc916y3 Freescale Semiconductor, Inc, mc68hc916y3 Datasheet - Page 123

• Manufacturer Part Number: mc68hc916y3
• Description: Mc68hc16y3 16 Bit Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

MC68HC16Y3/916Y3
USER’S MANUAL
EXTERNAL CLOCK?
SETUP INTERRUPT
TO WAKE UP MCU
ENTER LPSTOP
ON IN LPSTOP?
WANT CLKOUT
FROM LPSTOP
SET STEXT = 1
YES
YES
f
f
IN LPSTOP
clkout
eclk
USING
= f
2
= f
sys
sys
The internal oscillator which supplies the input frequency for the PLL
always runs when a crystal is used.
NO
NO
Freescale Semiconductor, Inc.
NOTES:
USE SYSTEM CLOCK
For More Information On This Product,
1. THE SCIMCLK IS USED BY THE PIT, IRQ, AND INPUT BLOCKS OF THE SCIM2.
2. CLKOUT CONTROL DURING LPSTOP IS OVERRIDDEN BY THE EXOFF BIT IN SCIMCR. IF EXOFF = 1, THE CLKOUT
AS SCIMCLK IN
SET STSCIM = 1
SET STEXT = 0
YES
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.
f
f
clkout
scimclk
IN LPSTOP
IN LPSTOP
f
LPSTOP?
eclk
Figure 5-6 LPSTOP Flowchart
2
= 0 Hz
1
= 0 Hz
= f
sys
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NO
NOTE
SET STSCIM = 0
ON IN LPSTOP?
WANT CLKOUT
SET STEXT = 1
YES
f
IN LPSTOP
IN LPSTOP
scimclk
f
f
clkout
eclk
= 0 Hz
2
1
= f
= f
ref
ref
NO
SET STEXT = 0
f
clkout
IN LPSTOP
f
eclk
2
= 0 Hz
= 0 Hz
MOTOROLA
LPSTOPFLOW
5-15