SH7261 datasheet(346/1348 Pages) RENESAS

346 / 1348 page

Section 11 Direct Memory Access Controller (DMAC)

Rev. 2.00 Sep. 07, 2007 Page 314 of 1312

REJ09B0320-0200

11.3.3

DMA Current Byte Count Register (DMCBCT)

DMCBCT is a register used to specify the number of bytes to be transferred by DMA.

The value in this register is transferred to the working byte-count register at the start of DMA

transfer, and is then decremented by the number of bytes transferred on each unit data transfer.

Decrementation is thus by the following values.

• When the transfer size is set to 8 bits (SZSEL = "000"): −1

• When the transfer size is set to 16 bits (SZSEL = "001"): −2

• When the transfer size is set to 32 bits (SZSEL = "010"): −4

When the value in the working byte count register reaches H'000 0000, DMA transfer ends (an

end due to byte count "0"). The corresponding bit of the DMA transfer end detection register

(DMEDET) is set to 1.

If the byte count reload function is disabled, the contents of the working byte count register are

returned to this register at the moment the channel for DMA transfer switches or DMA transfer

ends. If the byte count reload function is enabled, the contents of the DMA reload byte counter

This register must be set before transfer is initiated, regardless of whether the reload function is

enabled or disabled.

Bit:

Initial value:

R/W:

9876543210

Bit:

Initial value:

R/W:

——————————

R/W

————————————————

R/W

——————

CBC

Bit

Bit Name

Initial

Value

R/W

Description

31 to 26



All 0

Reserved

These bits are always read as 0. The write value

should always be 0.

25 to 0

CBC

Undefined R/W

Number of bytes to be DMA-transferred.

Notes: 1. Note that a setting of H'000 0000 leads to transfer of the maximum number of bytes, i.e.

64 Mbytes.

SH7261 Datasheet(PDF) 346 Page - Renesas Technology Corp

SH7261 Datasheet(HTML) 346 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

Datasheet Download

Link URL