r5s77631ay266bgv Renesas Electronics Corporation., r5s77631ay266bgv Datasheet - Page 674

Manufacturer Part Number

r5s77631ay266bgv

Renesas 32-bit Risc Microcomputer Superhtm Risc Engine Family Sh-4a Series

Manufacturer

Renesas Electronics Corporation.

Section 14 Direct Memory Access Controller (DMAC)

In a repeat mode transfer, a DMA transfer is repeated without specifying the transfer settings

every time before executing a transfer.

Using a repeat mode transfer with the half end function allows a double buffer transfer executed

virtually. Following processing can be executed effectively by using a repeat mode transfer. As an

example, operation of receiving voice data from the VOICE CODEC and compressing it is

In the following example, processing of compressing 40-word voice data every data reception is

explained. In this case, it is assumed that voice data is received by means of SIOF.

1. DMAC settings

• Set address of the SIOF receive data register in SAR

• Set address of an internal memory data store area in DAR

• Set TCR to H'50 (80 times)

• Satisfy the following settings of CHCR

• Set such as bits TB and TS[2:0] according to use conditions

• Set bits CMS[1:0] and PR[1:0] in DMAOR according to use conditions and set the DME bit to

2. Voice data is received and then transferred by SIOF/DMAC

3. TCR is decreased to half of its initial value and an interrupt is generated

After reading CHCR to confirm that the HE bit is set to 1 by an interrupt processing, clear the HE

bit to 0 and compress 40-word voice data from the address set in DAR.

4. TCR is cleared to 0 and an interrupt is generated

Rev. 1.00 Oct. 01, 2007 Page 608 of 1956

REJ09B0256-0100

Bits RPT[2:0] = B'010: Repeat mode (use DAR as a repeat area)

Bit HIE = B'1: TCR/2 interrupt generated

Bits DM[1:0] = B'01: DAR incremented

Bits SM[1:0] = B'00: SAR fixed

Bit IE = B'1: Interrupt enabled

Bit DE = B'1: DMA transfer enabled

After reading CHCR to confirm that the TE bit is set to 1 by an interrupt processing, clear the

TE bit to 0 and compress 40-word voice data from the address set in DAR + 40. After this

operation, the value of DARB is copied to DAR in DMAC and initialized, and the value of

TCRB is copied to TCR and initialized to 80.

Repeat Mode Transfer