Motorola MPC823e Reference Manual page 546

Communication Processor Module
16.6.3.2 IDMA PARAMETER RAM MEMORY MAP. The MPC823e uses the IDMA
parameters listed in the table below to configure the IDMA channel for autobuffer or buffer
chaining mode.
Table 16-21. IDMA Parameter RAM Memory Map
ADDRESS NAME
IDMA Base + 00 IBASE
IDMA Base + 02 DCMR
IDMA Base + 04 SAPR
IDMA Base + 08 DAPR
IDMA Base + 0C IBPTR
IDMA_Base +0E WRITE_SP
IDMA Base + 10 S_BYTE_C
IDMA Base + 14 D_BYTE_C
IDMA Base + 18 S_STATE
IDMA Base + 1C ITEMP
IDMA Base + 2C SR_MEM
IDMA Base + 30 READ_SP
IDMA Base + 32
IDMA Base + 34
IDMA Base + 36
IDMA Base + 38 D_STATE
NOTE: You are only responsible for initializing the items in bold.
IDMA Base = (IMMR & 0xFFFF0000) + 0x3CC0 (IDMA1) or 0x3DC0 (IDMA2).
All references to registers in the parameter RAM table are actually implemented in the dual-port RAM
area as a memory-based register.
• IBASE—This index pointer defines the starting point in the dual-port RAM for the set of
IDMA buffer descriptors. It is an offset from the beginning of the dual-port RAM. You
must initialize this entry before enabling the IDMA channel and if you overlap the buffer
descriptor tables of two enabled serial channels or IDMA channels, erratic behavior will
occur. IBASE must contain a value that is divisible by 16.
16-92
WIDTH
Half-word IDMA Buffer Descriptor Base Address Index Pointer
Half-word
Word
Word
Half-word
Half-word
Word
Word
Word
Four-word
Word
Half-word
— Half-word Difference Between Source and Destination Residue
— Half-word
— Half-word
Word
MPC823e REFERENCEMANUAL
DESCRIPTION
IDMA Channel Mode Register
Source Internal Address Pointer
Destination Internal Address Pointer
Buffer Descriptor Pointer
—
Internal Source Byte Count
Internal Destination Byte Count
Internal State
Temporary Data Storage
Data Storage for Peripheral Write
—
Temporary Storage Address Pointer
SR_MEM Byte Count
Internal State
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