System Development and Debugging
MPC885 PowerQUICC Family Reference Manual, Rev. 2
Freescale Semiconductor
53-23
53.3.1.5
Saving Machine State when Entering Debug Mode
If any load/store-type exception causes the store to enter debug mode, the critical information in DAR and
DSISR must be saved before any other operation is performed. Failing to do so can cause information loss
if the development software encounters another load/store-type exception. Because exceptions are treated
differently in debug mode, there is no need to save SRR0 and SRR1.
53.3.1.6
Running in Debug Mode
When running in debug mode, all fetch cycles access the development port, regardless of the cycle’s actual
address. 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 an SPR and is accessed using mtspr and mfspr via special
load/store cycles (see
Table 53-14
).
Exceptions are treated differently in debug mode; the ICR is updated on recognition of an exception
according to the event that caused it. A special error indication (ICR_OR) is asserted for one clock cycle
to notify the development port when an exception occurs. Execution continues in debug mode without
changing SRR0 and SRR1. To allow the development system to detect the excepting instruction, ICR_OR
is asserted before the next fetch. Not all exceptions are recognized in debug mode. Hardware does not
generate breakpoints and watchpoints in debug mode, regardless of the value of MSR[RI]. On entering
debug mode, MSR[EE] is cleared, forcing hardware to ignore external and decrementer interrupts.
Note that debug software must not set MSR[EE] in debug mode because the external interrupt event is a
level signal. Because the core only reports and does not handle exceptions in debug mode, core hardware
does not clear MSR[EE]. This event, if enabled, is recognized on every clock. When ICR_OR is asserted
the development station should read the ICR to find what event caused the exception. Because SRR0 and
SRR1 do not change, if an exception is recognized in debug mode, they change only once when entering
debug mode. However, saving SRR0 and SRR1 when entering debug mode is unnecessary.
53.3.1.7
Exiting Debug Mode
The rfi instruction is used to exit from debug mode to return to the normal processor operation and to
negate the freeze indication. The development system may monitor the FRZ or FLS pins to make sure the
MPC885 is out of debug mode. It is the responsibility of the debugger to read the ICR before performing
the rfi instruction. Failing to do so forces the core to immediately reenter debug mode and to reassert the
freeze indication if an asserted ICR bit has a corresponding enable bit set in the DER.
1
1
X
0
Branch to machine check interrupt
0x10000000
1
1
X
1
Enter debug mode
0x10000000
Table 53-9. Checkstop State and Debug Mode (continued)
MSR[ME]
Debug Mode
Enable
DER[CHSTPE] DER[MCIE]
Core Response to Machine Check
Interrupt
ICR Value
Содержание PowerQUICC MPC870
Страница 1: ...MPC885 PowerQUICC Family Reference Manual Supports MPC885 MPC880 MPC875 MPC870 MPC885RM Rev 2 04 2006 ...
Страница 98: ...MPC885 PowerQUICC Family Reference Manual Rev 2 I 4 Freescale Semiconductor ...
Страница 118: ...MPC885 Overview MPC885 PowerQUICC Family Reference Manual Rev 2 1 20 Freescale Semiconductor ...
Страница 158: ...The MPC8xx Core MPC885 PowerQUICC Family Reference Manual Rev 2 3 18 Freescale Semiconductor ...
Страница 192: ...MPC885 Instruction Set MPC885 PowerQUICC Family Reference Manual Rev 2 5 22 Freescale Semiconductor ...
Страница 242: ...Instruction and Data Caches MPC885 PowerQUICC Family Reference Manual Rev 2 7 30 Freescale Semiconductor ...
Страница 288: ...MPC885 PowerQUICC Family Reference Manual Rev 2 III 4 Freescale Semiconductor ...
Страница 416: ...External Bus Interface MPC885 PowerQUICC Family Reference Manual Rev 2 13 42 Freescale Semiconductor ...
Страница 440: ...Clocks and Power Control MPC885 PowerQUICC Family Reference Manual Rev 2 14 24 Freescale Semiconductor ...
Страница 554: ...MPC885 PowerQUICC Family Reference Manual Rev 2 V 6 Freescale Semiconductor ...
Страница 606: ...SDMA Channels and IDMA Emulation MPC885 PowerQUICC Family Reference Manual Rev 2 19 20 Freescale Semiconductor ...
Страница 738: ...SCC Asynchronous HDLC Mode and IrDA MPC885 PowerQUICC Family Reference Manual Rev 2 25 16 Freescale Semiconductor ...
Страница 780: ...SCC Ethernet Mode MPC885 PowerQUICC Family Reference Manual Rev 2 27 24 Freescale Semiconductor ...
Страница 794: ...SCC Transparent Mode MPC885 PowerQUICC Family Reference Manual Rev 2 28 14 Freescale Semiconductor ...
Страница 848: ...Serial Peripheral Interface SPI MPC885 PowerQUICC Family Reference Manual Rev 2 30 18 Freescale Semiconductor ...
Страница 882: ...Universal Serial Bus USB MPC885 PowerQUICC Family Reference Manual Rev 2 31 34 Freescale Semiconductor ...
Страница 944: ...Parallel I O Ports MPC885 PowerQUICC Family Reference Manual Rev 2 34 26 Freescale Semiconductor ...
Страница 956: ...CPM Interrupt Controller MPC885 PowerQUICC Family Reference Manual Rev 2 35 12 Freescale Semiconductor ...
Страница 1004: ...Buffer Descriptors and Connection Tables MPC885 PowerQUICC Family Reference Manual Rev 2 37 30 Freescale Semiconductor ...
Страница 1022: ...ATM Parameter RAM MPC885 PowerQUICC Family Reference Manual Rev 2 38 18 Freescale Semiconductor ...
Страница 1068: ...ATM Pace Control MPC885 PowerQUICC Family Reference Manual Rev 2 40 22 Freescale Semiconductor ...
Страница 1090: ...UTOPIA Interface MPC885 PowerQUICC Family Reference Manual Rev 2 43 8 Freescale Semiconductor ...
Страница 1120: ...AAL2 Implementation MPC885 PowerQUICC Family Reference Manual Rev 2 44 30 Freescale Semiconductor ...
Страница 1162: ...Fast Ethernet Controller FEC MPC885 PowerQUICC Family Reference Manual Rev 2 45 40 Freescale Semiconductor ...
Страница 1172: ...SEC Lite Overview MPC885 PowerQUICC Family Reference Manual Rev 2 46 8 Freescale Semiconductor ...
Страница 1176: ...SEC Lite Address Map MPC885 PowerQUICC Family Reference Manual Rev 2 47 4 Freescale Semiconductor ...
Страница 1214: ...SEC Lite Execution Units MPC885 PowerQUICC Family Reference Manual Rev 2 48 38 Freescale Semiconductor ...
Страница 1312: ...Byte Ordering MPC885 PowerQUICC Family Reference Manual Rev 2 A 8 Freescale Semiconductor ...
Страница 1313: ...MPC885 PowerQUICC Family Reference Manual Rev 2 Freescale Semiconductor B 1 Appendix B Serial Communications Performance TBD ...
Страница 1314: ...Serial Communications Performance MPC885 PowerQUICC Family Reference Manual Rev 2 B 2 Freescale Semiconductor ...
Страница 1320: ...Register Quick Reference Guide MPC885 PowerQUICC Family Reference Manual Rev 2 C 6 Freescale Semiconductor ...
Страница 1336: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 16 Freescale Semiconductor ...
Страница 1358: ...MPC885 PowerQUICC Family Reference Manual Rev 2 D 38 Freescale Semiconductor ...
Страница 1370: ...MPC880 MPC885 PowerQUICC Family Reference Manual Rev 2 E 4 Freescale Semiconductor ...
Страница 1384: ...Serial ATM Scrambling Reception and SI Programming MPC885 PowerQUICC Family Reference Manual Rev 2 H 6 Freescale Semiconductor ...
Страница 1386: ...Revision History MPC885 PowerQUICC Family Reference Manual Rev 2 I 2 Freescale Semiconductor ...