MC68HC08AZ0 Datasheet, PDF (308/444 Pages) Motorola, Inc – Advance Information

Freescale Semiconductor, Inc.
Programmable Interrupt Timer (PIT)
Bit 15
14
13
12
11
10
PCNTH ^{Read: Bit 15}
14
13
12
11
10
$004C _Write:
Reset: 0
0
0
0
0
0
9
Bit 8
9
Bit 8
0
0
Bit 7
6
5
4
3
2
1
Bit 0
PCNTL ^{Read: Bit 7}
6
5
4
3
2
1
Bit 0
$004D _Write:
0
0
0
0
0
0
0
0
Reset:
= Unimplemented
Figure 3. PIT counter registers (PCNTH:PCNTL)
PIT Counter
modulo registers
(PMODH:PMODL)
The read/write PIT modulo registers contain the modulo value for the
PIT counter. When the PIT counter reaches the modulo value, the over-
flow flag (POF) becomes set, and the PIT counter resumes counting
from $0000 at the next clock. Writing to the high byte (PMODH) inhibits
the POF bit and overflow interrupts until the low byte (PMODL) is writ-
ten. Reset sets the PIT counter modulo registers.
Bit 15
14
13
12
11
10
PMODH
$004E
Read:
Write:
Bit 15
14
13
12
11
10
Reset: 1
1
1
1
1
1
9
Bit 8
9
Bit 8
1
1
Bit 7
6
5
4
3
2
1
Bit 0
PMODL ^Read:
$004F _Write:
Bit 7
6
5
4
3
2
1
Bit 0
Reset: 1
1
1
1
1
1
1
1
Figure 4. PIT Counter modulo registers (TMODH:TMODL)
NOTE: Reset the PIT counter before writing to the PIT counter modulo registers.
MC68HC08AZ0
306
Programmable Interrupt Timer (PIT)
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8-pit
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