CHAPTER 12 NBD FUNCTION (
µµµµ
PD70F3116)
637
User’s Manual U14492EJ3V0UD
12.5 Control Registers
(1) RAM access data buffer register L (NBDL)
NBDL register operates as buffer between DMA and the NBD tool when reading or writing RAM via DMA
from the NBD tool.
NBDL 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.
14
D14
13
D13
12
D12
2
D2
3
D3
4
D4
5
D5
6
D6
7
D7
8
D8
9
D9
10
D10
11
D11
15
D15
1
D1
0
D0
NBDL
Address
FFFFFA60H
Initial value
0000H
Cautions 1. Although NBDL, NBDLU, and NBDLL registers can be used to read or write, physically
separate registers are used when reading and when writing and values written cannot be
read.
2. Use both NBDL and NBDH (refer to 12.5 (2)) registers 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)
NBDH register operates as buffer between DMA and the NBD tool when reading or writing RAM via DMA
from the NBD tool.
NBDH 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.
14
D30
13
D29
12
D28
2
D18
3
D19
4
D20
5
D21
6
D22
7
D23
8
D24
9
D25
10
D26
11
D27
15
D31
1
D17
0
D16
NBDH
Address
FFFFFA62H
Initial value
0000H
Cautions 1. Although NBDH, NBDHU, and NBDHL registers can be used to read or write, physically
separate registers are used when reading and when writing and values written cannot be
read.
2. Use both NBDL (refer to 12.5 (1)) and NBDH registers 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.
Содержание V850E/IA1 mPD703116
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