Register Descriptions; Dtc Mode Register A (Mra) - Hitachi H8S/2646 Hardware Manual

8.2

Register Descriptions

8.2.1

DTC Mode Register A (MRA)

Bit :
SM1
Initial value :
—
R/W :
MRA is an 8-bit register that controls the DTC operating mode.
Bits 7 and 6—Source Address Mode 1 and 0 (SM1, SM0): These bits specify whether SAR is
to be incremented, decremented, or left fixed after a data transfer.
Bit 7 Bit 6
SM1 SM0
0 —
1 0
1
Bits 5 and 4—Destination Address Mode 1 and 0 (DM1, DM0): These bits specify whether
DAR is to be incremented, decremented, or left fixed after a data transfer.
Bit 5 Bit 4
DM1 DM0
0 —
1 0
1
184
7 6 5
SM0 DM1
* * *
— —
Description
SAR is fixed
SAR is incremented after a transfer
(by +1 when Sz = 0; by +2 when Sz = 1)
SAR is decremented after a transfer
(by –1 when Sz = 0; by –2 when Sz = 1)
Description
DAR is fixed
DAR is incremented after a transfer
(by +1 when Sz = 0; by +2 when Sz = 1)
DAR is decremented after a transfer
(by –1 when Sz = 0; by –2 when Sz = 1)
4 3
DM0 MD1 MD0
* *
— —
2 1 0
DTS Sz
* * *
— — —
*: Undefined