7643 datasheet(212/424 Pages) RENESAS

212 / 424 page

Rev.2.00

Aug 28, 2006

page 91 of 202

7643 Group

REJ09B0133-0200

APPLICATION

2.5 DMAC

2.5.6 DMAC application example

(1) Transfer from external FIFO to USB FIFO

Outline: Data are transferred from external FIFOs to USB FIFOs.

Specifications: •A burst transfer is used and 128-byte (128 bytes/packet) continuous transfer is

performed. The external FIFO size must be set as 128 bytes of an integral multiple.

•If the data is deficient in the external FIFO, the DMAC channel 0 transferring is

stopped in the DMAC channel 0 interrupt routine process. The DMA transfer is

resumed in the main routine process when the data is sufficient.

•To confirm the external FIFO state after completion of 128 bytes transferring, set

the DMAC channel x disable after count register underflow enable bit (DxDAUE)

to “1”.

•USB endpoint 2 IN_PKT_RDY (falling edge) selected as hardware transfer request

source.

Figures 2.5.16 and 2.5.17 show a setting of the related registers and Figure 2.5.18 shows a control

procedure.

If data are transferred from USB FIFOs to external FIFOs as well as this, use USB endpoint 2

OUT_PKT_RDY (rising edge) selected as hardware transfer request source.

7643 Datasheet(PDF) 212 Page - Renesas Technology Corp