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12.5 Control Registers
(1) RAM access data buffer register L (NBDL)
The NBDL register operates as the buffer between the DMA controller and the NBD tool when reading or
writing RAM from the NBD tool via the DMA controller.
This register can be read/written in 16-bit units.
When the higher 8 bits of the NBDL register are used as the NBDLU register, and the lower 8 bits are used
as the NBDLL register, they can be read/written in 8-bit units.
15
14
13
NBDL
D15
D14
D13
Cautions 1. Although the NBDL, NBDLU, and NBDLL registers can be used for reading or writing,
physically separate registers are used when reading and when writing, so written values
cannot be read.
2. Use both the NBDL and NBDH registers (refer to 12.5 (2)) for 32-bit access of RAM.
Remark
Register values written from the NBD tool can be read by DMA (CPU) and values written by DMA
(CPU) can be read by the NBD tool.
(2) RAM access data buffer register H (NBDH)
The NBDH register operates as the buffer between the DMA controller and the NBD tool when reading or
writing RAM from the NBD tool via the DMA controller.
This register can be read/written in 16-bit units.
When the higher 8 bits of the NBDH register are used as the NBDHU register, and the lower 8 bits are used
as the NBDHL register, they can be read/written in 8-bit units.
15
14
13
NBDH
D31
D30
D29
Cautions 1. Although the NBDH, NBDHU, and NBDHL registers can be used for reading or writing,
physically separate registers are used when reading and when writing, so written values
cannot be read.
2. Use both the NBDL and NBDH registers (refer to 12.5 (1)) for 32-bit access of RAM.
Remark
Register values written from the NBD tool can be read by DMA (CPU) and values written by DMA
(CPU) can be read by the NBD tool.
634
CHAPTER 12 NBD FUNCTION (
12
11
10
9
8
7
D12
D11
D10
D9
D8
D7
12
11
10
9
8
7
D28
D27
D26
D25
D24
D23
User's Manual U14492EJ5V0UD
µ
PD70F3116)
6
5
4
3
2
1
D6
D5
D4
D3
D2
D1
6
5
4
3
2
1
D22
D21
D20
D19
D18
D17
0
Address
Initial value
D0
FFFFFA60H
0000H
0
Address
Initial value
D16
FFFFFA62H
0000H
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