XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 350

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Programmable Interrupt Timer (PIT)
21.8.2 PIT Counter Registers
Technical Data
350
NOTE:
Address: $004C
Address: $004D
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:
Reset:
Read:
Read:
Write:
Write:
Figure 21-4. PIT Counter Registers (PCNTH–PCNTL)
Bit 15
Bit 15
Bit 7
Bit 7
Programmable Interrupt Timer (PIT)
0
0
= Unimplemented
14
14
6
0
6
0
13
13
5
0
5
0
12
12
4
0
4
0
11
11
3
0
3
0
MC68HC908AZ60A — Rev 2.0
10
10
2
0
2
0
1
9
0
1
9
0
MOTOROLA
Bit 0
Bit 8
Bit 0
Bit 8
0
0