RL78/G1P
CHAPTER 13 DMA CONTROLLER
R01UH0895EJ0100 Rev.1.00
551
Nov 29, 2019
13.2.2 DMA RAM address register n (DRAn)
This is a 16-bit register that is used to set a RAM address that is the transfer source or destination of DMA channel n.
Addresses of the internal RAM area other than the general-purpose registers (see
Table 13-2
) can be set to this
register.
Set the lower 16 bits of the RAM address.
This register is automatically incremented when DMA transfer has been started. It is incremented by +1 in the 8-bit
transfer mode and by +2 in the 16-bit transfer mode. DMA transfer is started from the address set to this DRAn register.
When the data of the last address has been transferred, the DRAn register stops with the value of the last a1 in
the 8-bit transfer mode, and the last a2 in the 16-bit transfer mode.
In the 16-bit transfer mode, the least significant bit is ignored and is treated as an even address.
The DRAn register can be read or written in 8-bit or 16-bit units. However, it cannot be written during DMA transfer.
Reset signal generation clears this register to 0000H.
Figure 13-2. Format of DMA RAM Address Register n (DRAn)
Address: FFFB2H, FFFB3H (DRA0), FFFB4H, FFFB5H (DRA1) After reset: 0000H R/W
15
14
13
12
11
10 9 8 7 6 5 4 3 2 1 0
DRAn
(n = 0, 1)
Table 13-2. Internal RAM Area Other than the General-purpose Registers
Part Number
Internal RAM Area Other than the General-purpose Registers
RL78/G1P
FF900H to FFEDFH
Remark
n: DMA channel number (n = 0, 1)
DRA0H: FFFB3H
DRA1H: FFFB5H
DRA0L: FFFB2H
DRA1L: FFFB4H