
13.3 Registers and Register Details
MB90580 Series
Chapter 13: IE Bus
151
13.3.5 Mutliaddress, control bit set register (DCWR)
[bit 15, 14, 13, 12] DO3, DO2, DO1, DO0 (Multiaddress/normal communication select bits):
These bits are used to select multiaddress (more than one slave) or normal communication (one slave).
For multiaddress communication, DO3-0 is set to ‘0000’ and then the multiaddress bit in communica-
tion frame is sent out as ‘0’.
For normal communication, DO3-0 is set to ‘1000’ and then the multiaddress bit in communication
frame is sent out as ‘1’.
Always write ‘0’ to bit 14, 13, and 12, and when reading, these bits always return ‘0’.
[bit 11, 10, 9, 8] C3, C2, C1, C0 (Control bits):
These bits are used to control IEBus communication.
Note1:
The transfer direction of telegraph length bits in telegraph length field and data bits in data
field are controlled by the value of C3 as follows:
When C3 is ‘1’: Transfer from master unit to slave unit
When C3 is ‘0’: Transfer from slave unit to master unit
Note2:
3H, 6H, AH, BH are the lock and unlock function selection bits.
Note3:
When sending the undefined control bits like 1H, 2H, 8H, 9H, CH, DH, no acknowledge will be
returned.
Table 13.3.5a Control bits setting
C3
Note 1
0
0
0
0
C2
0
0
0
0
C1
0
0
1
1
C0
0
1
0
1
Control Operation
0H
1H
2H
3H
Slave status read
Undefined
Undefined
Data read and lock
Lock address read (Lower 8
bits)
Lock address read (Upper 4
bits)
Slave status read and unlock
Data read
Undefined
Undefined
Command write and lock
Data write and lock
Undefined
Undefined
Command write
Data write
4H
0
1
0
0
5H
0
1
0
1
6H
7H
8H
9H
AH
BH
CH
DH
EH
FH
0
0
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
C3
C2
DO0
15
14
13
12
11
10
9
8
DO1
DO3
DO2
DCWR
Address: 000075
H
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
(R/W)
(0)
C1
C0
Mutliaddress, control bit set register (DCWR)
Bit Number
Read/write
Initial value