s908ab32ag0cfue Freescale Semiconductor, Inc, s908ab32ag0cfue Datasheet - Page 227

• Manufacturer Part Number: s908ab32ag0cfue
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

13.7.2 PIT Counter Registers
MC68HC908AB32
Freescale Semiconductor
NOTE:
—
Rev. 1.1
Address:
PPS[2:0] — PIT Prescaler Select Bits
The two read-only PIT counter registers contain the high and low bytes
of the value in the PIT counter. Reading the high byte (PCNTH) latches
the contents of the low byte (PCNTL) into a buffer. Subsequent reads of
PCNTH do not affect the latched PCNTL value until PCNTL is read.
Reset clears the PIT counter registers. Setting the PIT reset bit (PRST)
also clears the PIT counter registers.
If you read PCNTH during a break interrupt, be sure to unlatch PCNTL
by reading PCNTL before exiting the break interrupt. Otherwise, PCNTL
retains the value latched during the break.
Reset:
Read:
Write:
PPS2
These read/write bits select one of the seven prescaler outputs as the
input to the PIT counter as
PPS[2:0] bits.
0
0
0
0
1
1
1
1
$004C
Bit 15
Bit 7
Programmable Interrupt Timer (PIT)
Figure 13-4. PIT Counter Register High (PCNTH)
0
PPS1
0
0
1
1
0
0
1
1
= Unimplemented
Table 13-1. PIT Prescaler Selection
14
6
0
PPS0
0
1
0
1
0
1
0
1
13
5
0
Table 13-1
12
4
0
Internal Bus Clock ÷1
Internal Bus Clock ÷ 2
Internal Bus Clock ÷ 4
Internal Bus Clock ÷ 8
Internal Bus Clock ÷ 16
Internal Bus Clock ÷ 32
Internal Bus Clock ÷ 64
Internal Bus Clock ÷ 64
PIT Clock Source
Programmable Interrupt Timer (PIT)
shows. Reset clears the
11
3
0
10
2
0
1
9
0
Technical Data
Bit 0
Bit 8
0
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