SH7041A datasheet(270/923 Pages) RENESAS

Part #	SH7041A

Description	Renesas 32-Bit Single-Chip RISC Microprocessor SuperH RISC engine Family/SH7040 Series(CPU Core SH-2)

PDF	923 Pages

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Manufacturer	RENESAS [Renesas Technology Corp]

Direct Link	http://www.renesas.com

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11.3.3

Channel Priority

When the DMAC receives simultaneous transfer requests on two or more channels, it selects a

channel according to a predetermined priority order, either in a fixed mode or in round robin

mode. These modes are selected by priority bits PR1 and PR0 in the DMA operation register

(DMAOR).

Fixed Mode: In these modes, the priority levels among the channels remain fixed.

The following priority orders are available for fixed mode:

• CH0 > CH1 > CH2 > CH3

• CH0 > CH2 > CH3 > CH1

• CH2 > CH0 > CH1 > CH3

These are selected by settings of the PR1 and PR0 bits of the DMA operation register (DMAOR).

Round Robin Mode: In round robin mode, each time the transfer of one transfer unit (byte, word

or long word) ends on a given channel, that channel receives the lowest priority level (figure 11.3).

The priority level in round robin mode immediately after a reset is CH0

> CH1 > CH2 > CH3.

SH7041A Datasheet(PDF) 270 Page - Renesas Technology Corp