H8SXSLASH1663R datasheet(522/1504 Pages) RENESAS

522 / 1504 page

Section 11 EXDMA Controller (EXDMAC)

Rev. 2.00 Sep. 24, 2008 Page 490 of 1468

REJ09B0412-0200

11.5.3

Activation Sources

The EXDMAC is activated by an auto request or an external request. This activation source is

selected by the DTF1 or DTF0 bit in EDMDR.

(1)

Activation by Auto-Request

The transfer request signal is automatically generated in EXDMAC with auto-request activation

when no transfer request signal is generated from external or peripheral modules, incase of

transfer among memory or between memory and peripheral modules that cannot generate the

transfer request signal. The transfer starts when the DTE bit in EDMDR is set to 1 with auto-

request activation. The bus mode can be selected from cycle steal mode and burst mode with auto-

request activation.

(2)

Activation by External Request

Transfer is started by the transfer request signal (

EDREQ) from the external device for activation

by an external request. When the EXDMA transfer is enabled (DTE = 1), the EXDMA transfer

starts by

EDREQ input.

The transfer request signal is accepted by the

EDREQ pin. The EDREQS bit in EDMDR selects

whether the

EDREQ is detected by falling edge sensing or low level sensing.

When the EDRAKE bit in EDMDR is set to 1, the signal notifying transfer request acceptance is

output from the

EDRAK pin. The EDRAK signal is accepted for one external request and is

output when transfer processing starts.

When specifying an external request as an activation source, set the DDR bit to 0 and the ICR bit

to 1 on the corresponding pin in advance. For details, see section 13, I/O Ports.

H8SX/1663R Datenblatt(PDF) 522 Page - Renesas Technology Corp