CHAPTER 7 DMAC
Preliminary User’s Manual A14874EJ3V0UM
152
7.5 Control Registers
7.5.1 DMA source address registers 0 to 3 (DSA0 to DSA3)
These registers are used to set the DMA transfer source addresses (28 bits each) for DMA channels n (n = 0 to 3).
They are divided into two 16-bit registers, DSAnH and DSAnL, respectively.
Since they are two-stage FIFO-configuration buffer registers, the transfer source address of a new DMA transfer
can be set during a DMA transfer (See
7.6 Next
Address Setting Function
).
When a flyby transfer is set according to the TTYP bit of the DMA addressing control registers n (DADCn), the
external memory addresses are set by the DSAn registers. At this time, any settings of the DMA destination address
registers n (DDAn) are ignored.
(1) DMA source address registers 0H to 3H (DSA0H to DSA3H)
These registers can be read or written in 16-bit units.
Figure 7-1. DMA Source Address Registers 0H to 3H (DSA0H to DSA3H)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
DSA0H
IR
0
0
0
SA
27
SA
26
SA
25
SA
24
SA
23
SA
22
SA
21
SA
20
SA
19
SA
18
SA
17
SA
16
Address
FFFFF082H
After reset
Undefined
DSA1H
IR
0
0
0
SA
27
SA
26
SA
25
SA
24
SA
23
SA
22
SA
21
SA
20
SA
19
SA
18
SA
17
SA
16
Address
FFFFF08AH
After reset
Undefined
DSA2H
IR
0
0
0
SA
27
SA
26
SA
25
SA
24
SA
23
SA
22
SA
21
SA
20
SA
19
SA
18
SA
17
SA
16
Address
FFFFF092H
After reset
Undefined
DSA3H
IR
0
0
0
SA
27
SA
26
SA
25
SA
24
SA
23
SA
22
SA
21
SA
20
SA
19
SA
18
SA
17
SA
16
Address
FFFFF09AH
After reset
Undefined
Bit position
Bit name
Function
15
IR
Specifies the DMA transfer source.
0: External memory or peripheral macro
1: RAM
11 to 0
SA27 to
SA16
Sets the DMA transfer source address (A27 to A16). During a DMA transfer, the next DMA
transfer source address is maintained. For a flyby transfer, the external memory address is
maintained.
Caution Bits 14 to 12 of the DSA0H to DSA3H registers must be set to 0. The operation when these
bits are set to 1 is not guaranteed.