SH7021 datasheet(198/509 Pages) RENESAS

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RENESAS 181

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Bits 9 and 8 (priority mode bits 1 and 0 (PR1 and PR0)): PR1 and PR0 select the priority level

between channels when there are transfer requests for multiple channels simultaneously.

Bit 9: PR1

Bit 8: PR0

Description

Fixed priority order (Ch. 0 > Ch. 3 > Ch. 2 > Ch. 1) (initial value)

Fixed priority order (Ch. 1 > Ch. 3 > Ch. 2 > Ch. 0)

Round-robin mode priority order (the priority order immediately

after a reset is Ch. 0 > Ch. 3 > Ch. 2 > Ch. 1)

External-pin round-robin mode priority order (the priority order

immediately after a reset is Ch. 3 > Ch. 2 > Ch. 1 > Ch. 0)

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Bits 7–3 (reserved): These bits always read 0. The write value should always be 0.

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Bit 2 (address error flag bit (AE)): AE indicates that an address error occurred in the DMAC.

When this flag is set to 1, the channel cannot be enabled even if the DE bit in the DMA

channel control register (CHCR) and the DME bit are set to 1. To clear the AE bit, read 1 from

it and then write 0. It is initialized to 0 by a reset or the standby mode.

Bit 2: AE

Description

No DMAC address error (initial value)

To clear the AE bit, read 1 from it and then write 0.

Address error by DMAC

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Bit 1 (NMI Flag Bit (NMIF)): NMIF indicates that an NMI interrupt occurred. When this flag

is set to 1, the channel cannot be enabled even if the DE bit in the CHCR and the DME bit are

set to 1. To clear the NMIF bit, read 1 from it and then write 0. It is initialized to 0 by a reset or

the standby mode.

Bit 1: NMIF

Description

No NMI interrupt (initial value)

To clear the NMIF bit, read 1 from it and then write 0.

NMI has occurred

SH7021 Datasheet(PDF) 198 Page - Renesas Technology Corp