mcf51ac256a Freescale Semiconductor, Inc, mcf51ac256a Datasheet - Page 493

• Manufacturer Part Number: mcf51ac256a
• Description: Mcf51ac Flexis
• Manufacturer: Freescale Semiconductor, Inc

Chapter 22
Version 1 ColdFire Debug (CF1_DEBUG)
22.1
Introduction
This chapter describes the capabilities defined by the Version 1 ColdFire debug architecture. The Version 1
ColdFire core supports BDM functionality using the HCS08’s single-pin interface. The traditional 3-pin
full-duplex ColdFire BDM serial communication protocol based on 17-bit data packets is replaced with
the HCS08 debug protocol where all communication is based on an 8-bit data packet using a single
package pin (BKGD).
An on-chip trace buffer allows a stream of compressed processor execution status packets to be recorded
for subsequent retrieval to provide program (and partial data) trace capabilities.
For this device, the Version 1 ColdFire debug architecture also supports optional visibility bus (VBus)
signals. The VBus signals support real-time program trace capabilities of arbitrarily-long instruction
streams.
The following sections in this chapter provide details on the BKGD pin, the background debug serial
interface controller (BDC), a standard 6-pin BDM connector, the BDM command set as well as real-time
debug and trace capabilities. The V1 definition supports revision B+ (DEBUG_B+) of the ColdFire debug
architecture.
A simplified block diagram of the V1 core including the processor and debug module is shown in
Figure
22-1.
MCF51AC256 ColdFire Integrated Microcontroller Reference Manual, Rev. 5
Freescale Semiconductor
22-1