Motorola MC68HC908AB32 - PIT Counter Modulo Registers

Programmable Interrupt Timer (PIT)
Technical Data MC68HC908AB32 — Rev. 1.0
228 Programmable Interrupt Timer (PIT) MOTOROLA
13.7.3 PIT Counter Modulo Registers
The read/write PIT modulo registers contain the modulo value for the PIT
counter. When the PIT counter reaches the modulo value, the overflow
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 written.
Reset sets the PIT counter modulo registers.
NOTE: Reset the PIT counter before writing to the PIT counter modulo registers.
Address: $004D
Bit 7 654321Bit 0
Read: Bit 7 654321Bit 0
Write:
Reset: 00000000
= Unimplemented
Figure 13-5. PIT Counter Register Low (PCNTL)
Address: $004E
Bit 7 654321Bit 0
Read:
Bit 15 14 13 12 11 10 9 Bit 8
Write:
Reset: 11111111
Figure 13-6. PIT Counter Modulo Register High (PMODH)
Address: $004F
Bit 7 654321Bit 0
Read:
Bit 7 654321Bit 0
Write:
Reset: 11111111
Figure 13-7. PIT Counter Modulo Register Low (PMODL)