Restriction for Using DMA Transfer

Apr,2007

Product Types

TOSHIBA Microcontrollers TX19 Family T19, TX19A Series

TMP1940CYAF/FG
TMP1940FDBF/FG
TMP1941AF/FG
TMP1942CYU
TMP1942CZUE
TMP1942FDU
TMP1942CZXBG
TMP1942FDXBG
TMP1962C10BXBG
TMP1962F10AXBG
TMP19A64C1DXBG
TMP19A64F20BXBG
TMP19A71FYFG
TMP19A71FYUG
TMP19A71CYFG
TMP19A71CYUG

With regard to the TOSHIBA microcontrollers listed above, please be advised that malfunctions may occur on DMA transfer.

Restriction / Problem

TOSHIBA microcontrollers listed above may cause malfunctions on DMA transfer using a memory - to - I/O transfer device if they meet all the conditions shown below.

1. The memory - to - I/O transfer is used as a transfer device.
2. The data destination is one of the following.
    a) Internal RAM
    b) External memory ( 0 WAIT, ALE assert: 1 clock )
    c) HSIO ( excluding SIO and SBI )
3. Two or more transfers are set.
      (BCRn ) > (CCRn ) < TrSiz >
4. Bus width has the same size as the data to be transferred.
      Data to be transferred (CCRn ) < DPS > = Device port size (CCRn ) < TrSiz >

Workaround

Please change the DMA transfer initial setting as shown below.

1. Fix the destination device to memory.
2. Set the source device depending on the transfer mode.
a) At single transfer: I/O device
b) At continuous transfer: Memory

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