mc68hc05p18a Freescale Semiconductor, Inc, mc68hc05p18a Datasheet - Page 68

• Manufacturer Part Number: mc68hc05p18a
• Description: Mc68hc05p18a Hcmos Microcontroller Unit
• Manufacturer: Freescale Semiconductor, Inc

16-Bit Timer
8.4 Output Compare
Technical Data
Address:
Address:
The output compare function may be used to generate an output
waveform and/or as an elapsed time indicator. All of the bits in the output
compare register pair, OCRH/OCRL, are readable and writable and are
not altered by the 16-bit timer’s control logic. Reset does not affect the
contents of these registers. If the output compare function is not utilized,
its registers may be used for data storage. See
The contents of the output compare registers are compared with the
contents of the free-running counter once every four PH2 clock cycles.
If a match is found, the output compare flag bit (OCF) is set and the
output level bit (OLVL) is clocked to the output latch. The values in the
output compare registers and output level bit should be changed after
each successful comparison to control an output waveform or to
establish a new elapsed timeout. An interrupt can also accompany a
successful output compare if the output compare interrupt enable bit
(OCIE) is set.
After a CPU write cycle to the MSB of the output compare register pair
(OCRH), the output compare function is inhibited until the LSB (OCRL)
is written. Both bytes must be written if the MSB is written. A write made
only to the LSB will not inhibit the compare function. The free-running
Reset:
Reset:
Read:
Read:
Write:
Write:
Freescale Semiconductor, Inc.
For More Information On This Product,
Figure 8-6. Output Compare Registers (OCRH/OCRL)
OCRH7
OCRL7
$0016
$0017
Bit 7
Bit 7
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OCRH6
OCRL6
6
6
16-Bit Timer
OCRH5
OCRL5
5
5
OCRH4
Unaffected by reset
Unaffected by reset
OCRL4
4
4
OCRH3
OCRL3
3
3
Figure
OCRH2
OCRL2
2
2
8-6.
OCRH1
OCRL1
MC68HC05P18A
1
1
OCRH0
OCRL0
Bit 0
Bit 0