Communication Processor Module
16-88
MPC823 USER’S MANUAL
MOTOROLA
SDMA
COMMUNICATION
16
PROCESSOR
MODULE
Bits 19–24 and 26–27—Reserved
These bits are reserved and should be set to 0.
LAID—LCD Controller Arbitration ID
This field determines the LCD and video controller arbitration ID. Its value should be
programmed to 00 for typical applications.
00 = The LCD controller uses U-Bus arbitration priority 6 (highest).
01 = The LCD controller uses U-Bus arbitration priority 5.
10 = The LCD controller uses U-Bus arbitration priority 2.
11 = The LCD controller uses U-Bus arbitration priority 1 (lowest).
RAID—RISC Controller Arbitration ID
These bits establish the priority level of bus arbitration among modules that can become bus
master. The instruction cache, data cache, system interface unit, and SDMAs all compete
for bus mastership. The SDMA channel arbitration ID is determined by the RAID field.
Arbitration IDs for all other bus masters are internally fixed. This value should be
programmed to 01 for typical applications.
00 = The SDMA uses U-Bus arbitration priority 6 (highest).
01 = The SDMA uses U-Bus arbitration priority 5.
10 = The SDMA uses U-Bus arbitration priority 2.
11 = The SDMA uses U-Bus arbitration priority 1 (lowest).
16.5.2.2 SDMA STATUS REGISTER. Shared by all 12 SDMA channels, the 8-bit
memory-mapped SDMA status register (SDSR) is used to report events recognized by the
SDMA controller. When an event is recognized, the SDMA sets the corresponding bit in the
SDSR. A bit is reset by writing a 1 (writing a zero has no effect) and more than one bit can
be reset at a time. This register is cleared by reset and can be read at any time.
SBER—SDMA Channel Bus Error (SDMA function)
This bit indicates that an error caused the SDMA channel to terminated during a read or
write cycle. The SDMA bus error address can be read from the SDMA address register.
Bits 1–5—Reserved
These bits are reserved and should be set to 0.
SDSR
BIT
0
1
2
3
4
5
6
7
FIELD
SBER
RESERVED
DSP2
DSP1
RESET
000
0
R/W
R/W
ADDR
(IMMR & 0xFFFF0000) + 0x908