Motorola MPC533 Reference Manual page 1014

RCPU Development Access
MCKO
MSEO
MDO[7:0]
TCODE = 8
Error Code = 0b00111 (Program/Data/Ownership trace overrun)
Figure 22-76. Error Message (Program/Data/Ownership Trace Overrun)
22.9 RCPU Development Access
This section details the RCPU development access support features of the READI module.
The READI development port provides a full duplex serial interface for accessing existing
RCPU user register and development features including BDM (background debug mode).
RCPU development access can be achieved either via the READI signals or the BDM
signals on the MCU. The access method is determined during READI module
configuration. Figure 22-77 shows how READI and BDM signals are multiplexed for
RCPU development access.
NOTEWhen the READI module is configured for RCPU development access, IEEE-ISTO
5001 compliant vendor-defined messages are used for transmission of data in and out of
On the MPC533 the BDM signals are shared with the READI
signals. Therefore BDM access is limited to access via the
Nexus vendor-defined development support messages.
Figure 22-77. RCPU Development Access Multiplexing
22.9.1 RCPU Development Access Messaging
The following RCPU development access messages are used for handshaking between the
device and the tool — DSDI data message, DSDO data message, and BDM status message.
22.9.1.1 DSDI Message
The DSDI message is used by the tool to download information to the RCPU.
The DSDI data field has a 3-bit status header followed by 7 or 32 bits of data/instruction,
depending on the RCPU development port mode.
22-82
PRELIMINARY—SUBJECT TO CHANGE WITHOUT NOTICE
11001000
the MCU.
between READI and BDM Signals
MPC533 Reference Manual
00000000
00000001
Don't care data
(idle clock)
MOTOROLA