H8SXSLASH1663 datasheet(861/1158 Pages) RENESAS

861 / 1158 page

Section 16 USB Function Module (USB)

Rev.1.00 Jun. 07, 2006 Page 809 of 1102

REJ09B0294-0100

16.8

DMA Transfer

16.8.1

Overview

DMA transfer can be performed for endpoints 1 and 2 in this module. Note that word or longword

data cannot be transferred.

When endpoint 1 holds at least one byte of valid receive data, a DMA request for endpoint 1 is

generated. When endpoint 2 holds no valid data, a DMA request for endpoint 2 is generated.

If the DMA transfer is enabled by setting the EP1DMAE bit in the DMA transfer setting register

to 1, zero-length data reception at endpoint 1 is ignored. When the DMA transfer is enabled, the

RDFN bit for EP1 and PKTE bit for EP2 do not need to be set to 1 in TRG (note that the PKTE bit

must be set to 1 when the transfer data is less than the maximum number of bytes). When all the

data received at EP1 is read, the FIFO automatically enters the EMPTY state. When the maximum

number of bytes (64 bytes) are written to the EP2 FIFO, the FIFO automatically enters the FULL

state, and the data in the FIFO can be transmitted (see figures 16.20 and 16.21).

16.8.2

DMA Transfer for Endpoint 1

When the data received at EP1 is transferred by the DMAC, the USB function module

automatically performs the same processing as writing 1 to the RDFN bit in TRG if the currently

selected FIFO becomes empty. Accordingly, in DMA transfer, do not write 1 to the RDFN bit in

TRG. If the user writes 1 to the RDFN bit in DMA transfer, correct operation cannot be

guaranteed.

Figure 16.20 shows an example of receiving 150 bytes of data from the host. In this case, internal

processing which is the same as writing 1 to the RDFN bit in TRG is automatically performed

three times. This internal processing is performed when the currently selected data FIFO becomes

empty. Accordingly, this processing is automatically performed both when 64-byte data is sent

and when data less than 64 bytes is sent.

RDFN

(Automatically

performed)

RDFN

(Automatically

performed)

RDFN

(Automatically

performed)

64 bytes

22 bytes

Figure 16.20 RDFN Bit Operation for EP1

H8SX/1663 数据表(PDF) 861 Page - Renesas Technology Corp

H8SX/1663 数据表(HTML) 861 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表下载

链接网址

H8SX/1663 数据表(PDF) 861 Page - Renesas Technology Corp

H8SX/1663 数据表(HTML) 861 Page - Renesas Technology Corp

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

数据表 下载

链接网址

数据表下载