Development Support
MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
23-27
0, debug mode is enabled and the check stop enable bit in the debug enable register (DER) is set, the CPU
enters debug mode rather then the check stop state.
The different actions taken by the CPU when a machine check interrupt is detected are shown in the
following table.
23.3.1.4
Saving Machine State upon Entering Debug Mode
If entering debug mode was as a result of any load/store type exception, and therefore the DAR (data
address register) and DSISR (data storage interrupt status register) have some significant value, these two
registers must be saved before any other operation is performed. Failing to save these registers may result
in loss of their value in case of another load/store type exception inside the development software.
Since exceptions are treated differently when in debug mode (refer to
Section 23.3.1.5, “Running in Debug
”), there is no need to save machine status save/restore zero register (SRR0) and machine status
save/restore one register (SRR1).
23.3.1.5
Running in Debug Mode
When running in debug mode all fetch cycles access the development port regardless of the actual address
of the cycle. All load/store cycles access the real memory system according to the cycle’s address. The data
register of the development port is mapped as a special control register therefore it is accessed using mtspr
and mfspr instructions via special load/store cycles (refer to
Section 23.6.13, “Development Port Data
”).
Exceptions are treated differently when running in debug mode. When already in debug mode, upon
recognition of an exception, the exception cause register (ECR) is updated according to the event that
caused the exception, a special error indication (ecr_or) is asserted for one clock cycle to report to the
development port that an exception occurred and execution continues in debug mode without any change
in SRR0 and SRR1. ECR_OR is asserted before the next fetch occurs to allow the development system to
detect the excepting instruction.
Table 23-9. Check Stop State and Debug Mode
MSR[ME]
Debug
Mode
Enable
CHSTPE
1
1
Check stop enable bit in the debug enable register (DER)
MCIE
2
2
Machine check interrupt enable bit in the debug enable register (DER)
Action Performed by the CPU when
Detecting a Machine Check Interrupt
Exception Cause
Register (ECR)
Value
0
0
X
X
Enter the check stop state
0x2000_0000
1
0
X
X
Branch to the machine check interrupt
0x1000_0000
0
1
0
X
Enter the check stop state
0x2000_0000
0
1
1
X
Enter Debug Mode
0x2000_0000
1
1
X
0
Branch to the machine check interrupt
0x1000_0000
1
1
X
1
Enter Debug Mode
0x1000_0000
Summary of Contents for MPC561
Page 84: ...MPC561 MPC563 Reference Manual Rev 1 2 lxxxiv Freescale Semiconductor...
Page 144: ...Signal Descriptions MPC561 MPC563 Reference Manual Rev 1 2 2 46 Freescale Semiconductor...
Page 206: ...Central Processing Unit MPC561 MPC563 Reference Manual Rev 1 2 3 62 Freescale Semiconductor...
Page 302: ...Reset MPC561 MPC563 Reference Manual Rev 1 2 7 14 Freescale Semiconductor...
Page 854: ...Time Processor Unit 3 MPC561 MPC563 Reference Manual Rev 1 2 19 24 Freescale Semiconductor...
Page 968: ...Development Support MPC561 MPC563 Reference Manual Rev 1 2 23 54 Freescale Semiconductor...
Page 1144: ...Internal Memory Map MPC561 MPC563 Reference Manual Rev 1 2 B 34 Freescale Semiconductor...
Page 1212: ...TPU3 ROM Functions MPC561 MPC563 Reference Manual Rev 1 2 D 60 Freescale Semiconductor...
Page 1216: ...Memory Access Timing MPC561 MPC563 Reference Manual Rev 1 2 E 4 Freescale Semiconductor...