
CHAPTER 20 DMA FUNCTION (DMA CONTROLLER)
User’s Manual U17790EJ2V0UD
879
20.3 Registers
(1) DMA source address registers 0 to 3 (DSA0 to DSA3)
The DSA0 to DSA3 registers set the DMA source addresses (26 bits each) for DMA channel n (n = 0 to 3).
These registers are divided into two 16-bit registers, DSAnH and DSAnL.
These registers can be read or written in 16-bit units.
External memory or on-chip peripheral I/O
Internal RAM
IR
0
1
Specification of DMA transfer source
Set the address (A25 to A16) of the DMA transfer source
(default value is undefined).
During DMA transfer, the next DMA transfer source address is held.
When DMA transfer is completed, the DMA address set first is held.
SA25 to SA16
Set the address (A15 to A0) of the DMA transfer source
(default value is undefined).
During DMA transfer, the next DMA transfer source address is held.
When DMA transfer is completed, the DMA address set first is held.
SA15 to SA0
After reset: Undefined
R/W
Address: DSA0H FFFFF082H, DSA1H FFFFF08AH,
DSA2H FFFFF092H, DSA3H FFFFF09AH,
DSA0L FFFFF080H, DSA1L FFFFF088H,
DSA2L FFFFF090H, DSA3L FFFFF098H
DSAnL
(n = 0 to 3)
SA15 SA14 SA13 SA12
SA6 SA5 SA4 SA3 SA2 SA1 SA0
SA7
SA8
SA9
SA10
SA11
DSAnH
(n = 0 to 3)
IR
000
SA22 SA21 SA20 SA19 SA18 SA17 SA16
SA23
SA24
SA25
0
Cautions 1. Be sure to clear bits 14 to 10 of the DSAnH register to 0.
2. Set the DSAnH and DSAnL registers at the following timing when DMA transfer is disabled
(DCHCn.Enn bit = 0).
Period from after reset to start of first DMA transfer
Period from after channel initialization by DCHCn.INITn bit to start of DMA transfer
Period from after completion of DMA transfer (DCHCn.TCn bit = 1) to start of the next
DMA transfer
3. When the value of the DSAn register is read, two 16-bit registers, DSAnH and DSAnL, are
read. If reading and updating conflict, the value being updated may be read (see 20.13
Cautions).
4. Following reset, set the DSAnH, DSAnL, DDAnH, DDAnL, and DBCn registers before
starting DMA transfer. If these registers are not set, the operation when DMA transfer is
started is not guaranteed.