MC68HC08LT8 Datasheet, PDF (71/156 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 7
Programmable Periodic Interrupt (PPI)
7.1 Introduction
This section describes the programmable periodic interrupt (PPI) module. The PPI will generate periodic
interrupts at user selectable rates using a counter clocked by the selected clock.
7.2 Features
Features of the PPI include:
• Seven user selectable periodic interrupts
• User selectable clock source:
– 32kHz (32KXCLK) clock from crystal oscillator
– External clock from PPIECK pin
7.3 Functional Description
The PPI module generates periodic interrupt requests to the CPU. When PPI counter reaches the defined
count, it generates an interrupt request. The latched status of interrupt generation of the PPI can be read
directly from the PPI1L bit.
The PPI counter can count and generate interrupts even when the MCU is in stop mode if the
corresponding clock source is enabled.
Figure 7-1 is a block diagram of the PPI.
MC68HC08LT8 Data Sheet, Rev. 1
Freescale Semiconductor
71