upd70f3017ay Renesas Electronics Corporation., upd70f3017ay Datasheet - Page 335

• Manufacturer Part Number: upd70f3017ay
• Description: V850/sa1tm 32-/16-bit Single-chip Microcontroller
• Manufacturer: Renesas Electronics Corporation.

(3) DMA byte count registers 0 to 2 (DBC0 to DBC2)
(n = 0 to 2)
After reset:
DBCn
These are 8-bit registers that are used to set the number of transfers for DMA channel n.
The remaining number of transfers is retained during the DMA transfers.
A value of 1 is decremented once per transfer if the transfer is a byte (8-bit) transfer, and a value of 2 is
decremented once per transfer if the transfer is a 16-bit transfer. The transfers are terminated when a borrow
operation occurs. Accordingly, “number of transfers − 1” should be set for byte (8-bit) transfers and “(number of
transfers − 1) × 2” should be set for 16-bit transfers. During 16-bit transfers, values set to bit 0 are ignored, and 0
is set to bit 0 after decrementation.
These registers are can be read/written in 8-bit units.
Caution Values set to bit 0 are ignored during 16-bit transfers.
Undefined R/W
BCn7
7
BCn6
6
Address:
CHAPTER 12 DMA FUNCTIONS
BCn5
5
User’s Manual U12768EJ4V1UD
DBC0
DBC1
DBC2
BCn4
4
FFFFF184H
FFFFF194H
FFFFF1A4H
BCn3
3
BCn2
2
BCn1
1
BCn0
0
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