mc68hc908as60 Freescale Semiconductor, Inc, mc68hc908as60 Datasheet - Page 383

• Manufacturer Part Number: mc68hc908as60
• Description: Mc68hc908as60 Microcontroller
• Manufacturer: Freescale Semiconductor, Inc

22.4.3.2 Buffered Output Compare
MC68HC908AS60 — Rev. 1.0
Use these methods to synchronize unbuffered changes in the output
compare value on channel x:
Channels 0 and 1 can be linked to form a buffered output compare
channel whose output appears on the PTE2/TACH0 pin. The TIMA
channel registers of the linked pair alternately control the output.
Setting the MS0B bit in TIMA channel 0 status and control register
(TASC0) links channel 0 and channel 1. The output compare value in the
TIMA channel 0 registers initially controls the output on the
PTE2/TACH0 pin. Writing to the TIMA channel 1 registers enables the
TIMA channel 1 registers to synchronously control the output after the
TIMA overflows. At each subsequent overflow, the TIMA channel
registers (0 or 1) that control the output are the ones written to last.
TASC0 controls and monitors the buffered output compare function, and
TIMA channel 1 status and control register (TASC1) is unused. While the
MS0B bit is set, the channel 1 pin, PTE3/TACH1, is available as a
general-purpose I/O pin.
Channels 2 and 3 can be linked to form a buffered output compare
channel whose output appears on the PTF0/TACH2 pin. The TIMA
channel registers of the linked pair alternately control the output.
•
•
Freescale Semiconductor, Inc.
For More Information On This Product,
When changing to a smaller value, enable channel x output
compare interrupts and write the new value in the output compare
interrupt routine. The output compare interrupt occurs at the end
of the current output compare pulse. The interrupt routine has until
the end of the counter overflow period to write the new value.
When changing to a larger output compare value, enable
channel x TIMA overflow interrupts and write the new value in the
TIMA overflow interrupt routine. The TIMA overflow interrupt
occurs at the end of the current counter overflow period. Writing a
larger value in an output compare interrupt routine (at the end of
the current pulse) could cause two output compares to occur in the
same counter overflow period.
Timer Interface Module A (TIMA-6)
Go to: www.freescale.com
Timer Interface Module A (TIMA-6)
Functional Description
Technical Data