H8SSLASH2218 datasheet(570/750 Pages) RENESAS

570 / 750 page

Section 14 Universal Serial Bus (USB)

Rev.6.00 Jun. 03, 2008 Page 522 of 698

REJ09B0074-0600

(b) EP2 DMA transfer procedure

Perform DMAC transfer in 1 packet units. After setting the EP2READY flag, check the size of

data received from the host and then set the data size as the number of DMAC transfers.

1. Set the bits EP2T1 and EP2T0 in UDMAR.

2. Wait for the EP2READY flag in UIFR1 to be set.

3. Set DMAC.

Read the value in UESZ2 and specifies the size of received data (not more than 64 bytes) as the

number of transfers.

4. Activate DMAC.

5. Perform DMA transfer (not more than 64 bytes).

6. Wait for DMA transfer end.

7. Repeat steps 2 to 6.

EP2RDFN

(Automatically

performed)

EP2RDFN

(Automatically

performed)

EP2RDFN

(Automatically

performed)

64 bytes

22 bytes

Figure 14.23 EP2RDFN Operation in UTRG0

14.6.2

DMA Transfer by Auto-Request

(1) Overview

Burst mode transfer or ycle steal transfer can be selected for the on-chip DMAC auto-request

transfer. Endpoints that can be transferred by the on-chip DMAC are all registers (UEDR0s,

UEDR0i, UEDR0o, UEDR1, UEDR2, UEDR3). Confirm flags and interrupts corresponding to

each data register before activating the DMA. As UDMAR is not used in auto-request mode, set

UDMAR to H'00.

(2) On-Chip DMAC Settings

The on-chip DMAC must be specified as follows: Auto-request, byte size, full-address mode

transfer, and number of transfers equal to or less than the maximum packet size of the data

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