MCF548x Reference Manual, Rev. 3
Freescale Semiconductor 25-1

Chapter 25

Comm Timer Module (CTM)

25.1 Introduction

This chapter contains a detailed description of the Comm Timer Module (CTM).

25.1.1 Block Diagrams

The following section presents three block diagrams showing the CTM in greater detail. Figure 25-1 is a
high level block diagram of the CTM. The figure shows the signal flow through the sub-modules and the
architecture on a high level.
Figure 25-1. CTM High Level Block Diagram
Figure 25-2 and Figure 25-3 are conceptual block diagrams of the fixed timer channel and variable timer
channel respectively. These diagrams are more detailed than earlier diagrams but should still be considered
a conceptual illustration of the actual hardware implementations.
cAcknowledge[7:0]
cInitiator
Synchronizer
Register Timer
Variable
TimerChannel[0]
Register Timer
Fixed
TimerChannel[0]
Write/Read
Enable
Logic
Addr
Decode
Logic
8-bit
Prescaler
externalClkIn[7:0]
clk
cAcknowledge[7:0]
Register Timer
Variable
TimerChannel[n]
Register Timer
Fixed
TimerChannel[n]
timerInterrupt
cInitiator
Comm Timer
Module
Internal Data_bus
Internal
Bus