6 DMA CONTROLLER (DMAC)
6-4
Seiko Epson Corporation
S1C31D50/D51 TECHNICAL MANUAL
(Rev. 2.00)
6.4.3 Control Data
Set the DMA transfer information. Figure 6.4.3.1 shows the constituent elements of the control data.
dst_inc
31 30
dst_size
29 28
src_inc
27 26
src_size
cycle_ctrl
R_power
n_minus_1
25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Reserved
Figure 6.4.3.1 Constituent Elements of Control Data
dst_inc
Set the increment value of the transfer destination address. The setting value must be equal to or larger than the
transfer data size when the address is incremented.
Table 6.4.3.1 Increment Value of Transfer Destination Address
dst_inc
Increment value
0x3
No increment
0x2
+4
0x1
+2
0x0
+1
dst_size
Set the size of the data to be written to the transfer destination. It should be the same value as the src_size.
Table 6.4.3.2 Size of Data Written to Transfer Destination
dst_size
Data size
0x3
Reserved
0x2
Word
0x1
Halfword
0x0
Byte
src_inc
Set the increment value of the transfer source address. The setting value must be equal to or larger than the
transfer data size when the address is incremented.
Table 6.4.3.3 Increment Value of Transfer Source Address
src_inc
Increment value
0x3
No increment
0x2
+4
0x1
+2
0x0
+1
src_size
Set the size of the data to be read from the transfer source. It should be the same value as the dst_size.
Table 6.4.3.4 Size of Data Read from Transfer Source
src_size
Data size
0x3
Reserved
0x2
Word
0x1
Halfword
0x0
Byte
R_power
Set the arbitration cycle during successive data transfer.
Arbitration cycle (2
R
) = 2
R_power
When the DMAC is performing a successive transfer, it suspends the data transfer at the cycle set with R_pow-
er. If DMA requests have been issued at that point, the DMAC re-arbitrates them according to their priorities
and then performs a DMA transfer for the channel with the highest priority.