169
Chapter 6
DMA Functions (DMA Controller)
Preliminary User’s Manual U14913EE1V0UM00
6.3.3 DMA transfer count registers 0 to 3 (DBC0 to DBC3)
These 16-bit registers are used to set the transfer counts for DMA channels n (n = 0 to 3). They store
the remaining transfer counts during DMA transfer.
Since these registers are configured as 2-stage FIFO buffer registers, a new DMA transfer count for
DMA transfer can be specified during DMA transfer. (Refer to 6.9 Next Address Setting Function)
During DMA transfer these registers are decremented by 1 for each transfer that is performed. DMA
transfer is terminated when an underflow occurs (from 0 to FFFFH). On terminal count these registers
are rewritten with the value that was set immediately before. (Refer to 6.9 Next
Function)
These registers can be read/written in 16-bit units.
Figure 6-6: DMA Transfer Count Registers 0 to 3 (DBC0 to DBC3)
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Address
Initial
value
DBC0
BC15 BC14 BC13 BC12 BC11 BC10 BC9 BC8 BC7 BC6 BC5 BC4 BC3 B2C BC1 BC0 FFFFF0C0H undef.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Address
Initial
value
DBC1
BC15 BC14 BC13 BC12 BC11 BC10 BC9 BC8 BC7 BC6 BC5 BC4 BC3 B2C BC1 BC0 FFFFF0C2H undef.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Address
Initial
value
DBC2
BC15 BC14 BC13 BC12 BC11 BC10 BC9 BC8 BC7 BC6 BC5 BC4 BC3 B2C BC1 BC0 FFFFF0C4H undef.
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
Address
Initial
value
DBC3
BC15 BC14 BC13 BC12 BC11 BC10 BC9 BC8 BC7 BC6 BC5 BC4 BC3 B2C BC1 BC0 FFFFF0C6H undef.
Bit Position
Bit Name
Function
15 to 0
BC15 to
BC0
Sets the transfer count. It stores the remaining transfer count during DMA transfer.
DBCn
States
0000H
Transfer count 1 or remaining transfer count
0001H
Transfer count 2 or remaining transfer count
:
:
FFFFH
Transfer count 65,536 (2
16
) or remaining transfer count
Summary of Contents for V850E/CA1 ATOMIC
Page 6: ...6 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 52: ...52 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 144: ...144 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 162: ...162 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 224: ...224 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 308: ...308 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 512: ...512 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 564: ...564 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 566: ...566 Preliminary User s Manual U14913EE1V0UM00 MEMO ...
Page 584: ...584 Preliminary User s Manual U14913EE1V0UM00 MEMO ...