Fujitsu FR81S User Manual
CHAPTER 8: DMA CONTROLLER (DMAC)
4. Registers
FUJITSU SEMICONDUCTOR LIMITED
CHAPTER : DMA CONTROLLER (DMAC)
FUJITSU SEMICONDUCTOR CONFIDENTIAL
15
[bit9, bit8] DAC (Destination Address Count) : Transfer destination address count
These bits specify the address update once for each transfer of the transfer destination address. The update
values when specifying "increment/decrement" will be one of the values, 1, 2, 4 depending on the transfer
size (DCCRn:TS).
DAC[1:0]
Transfer destination address count
00
Address increment (initial value)
01
Address decrement
10
Reserved (setting is prohibited)
11
Address fixed
[bit7] TCR (Transfer Count Reload) : Transfer count reload
This bit specifies the transfer count register reload.
When specifying a reload, the transfer count register value is returned to the initial value at the end of the
transfer. If the transfer request source is set other than "software", DCCRn:CE bit will not be cleared at the
end of the transfer and the operation will go into the transfer request wait state. When disabling a reload, the
transfer count register value at the end of the transfer will point to "0". In this case, DCCRn:CE bit will be
cleared at the end of the transfer regardless of the transfer request source.
TCR
Transfer count reload
0
Reload disabled (initial value)
1
Reload
[bit6] Reserved
Always write "0" to this bit. The read value is "0".
[bit5, bit4] TS (Transfer Size) : Transfer size
These bits specify the transfer size. DMA transfers will be performed once with the bit width specified here.
TS[1:0]
Transfer size
00
8-bit :byte (initial value)
01
16-bit :half-word
10
32-bit :word
11
Reserved (setting is prohibited)
Set values to DSARn and DDARn registers so as not to cause a misalignment for the transfer size specified
in these bits.
MB91520 Series
MN705-00010-1v0-E
314