SDMA Channels and IDMA Emulation
MPC8260 PowerQUICC II Family Reference Manual, Rev. 2
Freescale Semiconductor 19-19
19.8.2.1 DMA Channel Mode (DCM)

The IDMA channel mode (DCM), shown in Figure19-9, is a 16-bit field within the IDMA parameter

RAM, that controls the operation modes of the IDMA channel. As are all other IDMA parameters, the

DCM is undefined at reset.

Table19-5 describes DC M bits.

0x16 DTS Hword Destination transfer size in bytes. All transfers to destination (except the start
alignment and the tail) are written to the bus using this parameter.
In peripheral-to-memory mode, DTS should equal SS_MAX.
In memory-to-peripheral modes, initialize DTS to the peripheral port size if
transfer’s destination is a peripheral. Valid sizes for peripheral destination is 1,
2, 4, and 8 bytes, or peripheral transfer size (if the peripheral accepts bursts).
See Table19-8. for valid STS values for peripherals.
In fly-by mode, DTS is initialized to the peripheral port size.
In memory-to-memory mode:
• D TS value is initialized to SS_MAX.
• STS value is initialized to SS_MAX. DTS can be initialized to values other
than SS_MAX in the following conditions:
– DTS must divide SS_MAX.
– DTS must be divided by 32, to enable bursts in steady-state phase.
• See Table 19-8. for valid memory-to-memory DTS values.
0x18 RET_ADD Hword Used to save return address when working in ERM = 1 mode.
0x1A Hword Reserved, should be cleared.
0x1C BD_CNT Word Internal byte count.
0x20 S_PTR Word Source internal data pointer.
0x24 D_PTR Word Destination internal data pointer.
0x28 ISTATE Word Internal. Should be cleared before every START_IDMA command.
1From the pointer value programmed in IDMA
x
_BASE: IDMA1_BASE at 0x87FE, IDMA2_BASE at 0x88FE,
IDMA3_BASE at 0x89FE, and IDMA4_BASE at 0x8AFE; see Section14.5.2, “Parameter RAM.”
0 1 2 4 5 6 7 9 10 11 12 13 14 15
Field FB LP TC2 DMA_WRAP SINC DINC ERM DT S/D
Reset —
R/W R/W

Figure19-9. DCM Parameters

Table19-4. IDMA

x

Parameter RAM (continued)

Offset 1Name Width Description