MC9S12XDP512CFU
Model | MC9S12XDP512CFU |
Description | 16-BIT, FLASH, 40MHz, MICROCONTROLLER, PQFP80 |
PDF file | Total 1348 pages (File size: 8M) |
Chip Manufacturer | PHILIPS |
Chapter 13
Periodic Interrupt Timer (S12PIT24B4CV1)
13.1
Introduction
The period interrupt timer (PIT) is an array of 24-bit timers that can be used to trigger peripheral modules
or raise periodic interrupts. Refer to
Figure 13-1
for a simplified block diagram.
13.1.1
Glossary
Acronyms and Abbreviations
PIT
ISR
CCR
SoC
Periodic Interrupt Timer
Interrupt Service Routine
Condition Code Register
System on Chip
clock periods of the 16-bit timer modulus down-counters, which are generated by the 8-bit
modulus down-counters.
micro time bases
13.1.2
Features
The PIT includes these features:
• Four timers implemented as modulus down-counters with independent time-out periods.
• Time-out periods selectable between 1 and 2
24
bus clock cycles. Time-out equals m*n bus clock
cycles with 1 <= m <= 256 and 1 <= n <= 65536.
• Timers that can be enabled individually.
• Four time-out interrupts.
• Four time-out trigger output signals available to trigger peripheral modules.
• Start of timer channels can be aligned to each other.
13.1.3
Modes of Operation
Refer to the SoC guide for a detailed explanation of the chip modes.
• Run mode
This is the basic mode of operation.
• Wait mode
MC9S12XDP512 Data Sheet, Rev. 2.21
Freescale Semiconductor
541