
MOTOROLA
Chapter 23. READI Module
23-91
RCPU Development Access
development access is via debug mode pins. This is the default setting (DPA=0b0,
DME=0bX, DOR=0bX in DC register).
NOTE
The READI module will ignore any incoming DSDI data
messages when the module is not configured for RCPU
development access.
23.10.2.2 Enabling Background Debug Mode (BDM) via READI Pins
After RCPU development access has been enabled via the READI pins, debug mode is
enabled by setting bits in the DC register (DPA=0b1, DME=0b1, DOR=0b0).
23.10.2.3 Entering Background Debug Mode (BDM) Via READI Pins
There are three ways to enter debug mode (provided debug mode has been enabled):
1. Enter debug mode (halted state) out-of-system reset through READI module
2. Enter debug mode by downloading breakpoint instructions through RCPU
development access when in non-debug (running) mode.
3. Enter debug mode if an exception or interrupt occurs.
When entering debug mode following an exception/breakpoint, the RCPU signals
VFLS[0:1] are equal to 0b11. This causes READI to send a BDM status message to the tool
indicating that the RCPU has entered debug mode and is now expecting instructions from
the READI pins.
Debug mode enabling through READI and entering debug mode out of system reset is done
by setting the following bits in the DC register (DPA=0b1, DME=0b1, DOR=0b1) during
system reset. Debug mode entry causes RCPU to halt.
23.10.2.4 Non-Debug Mode Access of RCPU Development Access
The RCPU development access can be also be used while the RCPU is not halted (in debug
mode). This feature is used to send in breakpoints or synchronization events to the RCPU.
Please refer to the RCPU Reference Manual for further details.
Non-debug mode access of RCPU development can be achieved by configuring the READI
module to take control of RCPU development access during module configuration of the
DC register (DPA=0b1, DME=0b0, DOR=0bx).
23.10.2.5 RCPU Development Access Flow Diagram
Figure 23-80 has flow diagram describing how the RCPU development access can be
achieved via READI pins.