Reset
MPC561/MPC563 Reference Manual, Rev. 1.2
7-4
Freescale Semiconductor
7.3
Data Coherency During Reset
The MPC561/MPC563 supports data coherency and avoids data corruption during reset. If a cycle is
executing when any SRESET or HRESET source is detected, then the cycle will either complete or will
not start before generating the corresponding reset control signal. There are reset sources, however, when
the MPC561/MPC563 generates an internal reset due to special internal situations where this protection is
not supported. See
Section 7.4, “Reset Status Register (RSR)
In the case of large operand size (32 or 16 bits) transactions to a smaller port size, the cycle is split into
two 16-bit or four 8-bit cycles. In this case, data coherency is assured and data will not be corrupted.
In the case where the core executes an unaligned load/store cycle which is broken down into multiple
cycles, data coherency is NOT assured between these cycles (i.e., data could be corrupted).
Contention may occur if a write access is in progress to external memory and SRESET/HRESET is
asserted and the external reset configuration word (RCW) is used. In this case, the external RCW drivers,
usually activated by HRESET/SRESET lines, will drive the data bus together with the MPC561/MPC563.
Thus the data in the RAM may be corrupted regardless of the data coherency mechanism in the
MPC561/MPC563.
Table 7-1. Reset Action Taken for Each Reset Cause
Reset Source
Reset
Logic and
PLL
States
Reset
System
Configuratio
n Reset
Clock
Module
Reset
HRESET
Pin
Driven
Debug Port
Configuratio
n
Other
Internal
Logic
Reset
SRESET
Pin
Driven
Power-On Reset
(PORESET)
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Hard Reset (HRESET)
Sources:
• External Hard Reset
• Loss of Lock
• On-Chip Clock Switch
• Illegal Low-Power Mode
• Software Watchdog
• Checkstop
• Debug Port Hard Reset
No
Yes
Yes
Yes
Yes
Yes
Yes
Soft Reset (SRESET)
Sources:
• External Soft Reset
• Debug Port Soft Reset
• JTAG Reset
No
No
No
No
Yes
Yes
Yes
Table 7-2. Reset Configuration Word and Data Corruption/Coherency
Reset Driven
Reset to Use for Data
Coherency (EXT_RESET)
Comments
HRESET SRESET
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...
