MPC561/MPC563 Reference Manual, Rev. 1.2
Freescale Semiconductor
22-1
Chapter 22
CALRAM Operation
The calibration static random access memory (CALRAM) module provides the MPC561/MPC563 with a
general purpose memory that may be read from or written to as either bytes, half-words, or words. In
addition to this, a portion of the CALRAM, called the overlay region, can be used for calibration.
Calibration in this context is defined as overlaying portions of the U-bus Flash with a portion of the
CALRAM array. During normal Flash access, the RISC central processing unit (RPCU) reads data from
U-bus Flash (through L-bus and L2U) as shown in
. During calibration access, instead of Flash
providing the data, the overlay regions of CALRAM provide the data to the RPCU.
22.1
Features
Standard CALRAM features are listed below:
•
One-clock accesses
— Two-cycle access for power savings
•
Byte, half-word (16-bits), or word (32-bit) read/write accesses
•
Each 8-Kbyte block has individual protection control bits.
•
Low power standby operation for data retention
Special overlay features are:
•
Eight overlay regions; each can be programmed to be 4-, 16-, 32-, 64-, 128-, 256-, or 512-bytes
long
•
Each overlay region size can be forced to 4 bytes long
•
Data driven from the CALRAM module for overlay access has the same timing as the data that
would have come from the U-bus Flash
•
Overlay is for data read from the U-bus Flash space and does not affect instruction fetches from
the Flash
•
Overlay block is naturally aligned
— For example, 128-byte block is 128-byte aligned
•
Normal access to overlaid portion of CALRAM array can be made to generate an error (machine
check) if so configured
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...