13 DMA CONTROLLER (DMAC)
13-4
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S1C33L26 TECHNICAL MANUAL
TC[11:0]: Transfer counter (D[23:12]/1st word)
Set the number of times for unit data transfers to be executed. Writing 0x1 to 0xfff sets the transfer count to 1 to
4,095 and writing 0x0 sets it to 4,096. After a transfer of the data unit specified in UNIT[2:0] is completed, the
transfer counter is decremented.
ST: Source type (D11/1st word)
Selects whether the memory contents on the specified source address are used as data or pointers.
ST = 0: Data
The DMAC transfers the data stored in the source address to the destination address.
ST = 1: Pointer
The DMAC uses the specified source address as a pointer and determines the address in which transfer data
is stored as follows:
Transfer data = *(Pointer base a *(Source address))
Example: When base address (PTBASE[31:16]) = 0x85 (i.e., address 0x850000), source address
(SRADR[31:0]) = 0xfc000, and the contents of address 0xfc000 = 0x2
The data stored in address 0x850002 is transferred.
UNIT[2:0]: Transfer data unit (D[10:8]/1st word)
Sets the data size for the transfer unit.
3.2.2 Transfer Data Unit
Table 13.
UNIT[2:0]
Transfer data unit
0x7–0x3
Reserved
0x2
32 bits
0x1
16 bits
0x0
8 bits
SRINC[1:0]: Source address control (D[7:6]/1st word)
Sets the control method for the source address after a unit data transfer.
3.2.3 Source Address Control
Table 13.
SRINC[1:0]
Source address control
0x3–0x2
Reserved
0x1
Increment
0x0
Fixed
SRINC[1:0] = 0x0: Address fixed
The source address is not changed by a data transfer performed. Even when transferring multiple data, the
transfer data is always read from the same address.
SRINC[1:0] = 0x1: Address increment
After a transfer of a data unit specified with UNIT[2:0] is completed, the source address is incremented for
the transferred data unit. The address that has been incremented during transfer does not return to the initial
value.
DSINC[1:0]: Destination address control (D[5:4]/1st word)
Sets the control method for the destination address after a unit data transfer.
3.2.4 Destination Address Control
Table 13.
DSINC[1:0]
Destination address control
0x3–0x2
Reserved
0x1
Increment
0x0
Fixed
DSINC[1:0] = 0x0: Address fixed
The destination address is not changed by a data transfer performed. Even when transferring multiple data,
the transfer data is always written to the same address.