UPD72042A Datasheet, PDF (38/92 Pages) NEC – LSI DEVICES FOR Inter Equipment BusTM (IEBusTM) PROTOCOL CONTROL

µPD72042A, 72042B
MCR
Master communication register
Address : 0110B (6H)
Read/write : Write
When reset : Undefined (the pre-
vious data is held)
The MCR register is used to set a master communication condition.
Set MCR while the value of MARQ of the FLG register is 0 (while master communication is not requested).
b7
b6
b4
Broadcast bit Number of arbitrations
b3
Control bits
b0
MCR
[Broadcast bit]
This bit is used to select broadcast or separate communication.
Bit 7 = 0: Broadcast
Bit 7 = 1: Separate communication
[Number of arbitrations] (Number of retries)
This field is used to set the maximum number of retry operations to be performed if arbitration is lost in master
communication. The µPD72042A and µPD72042B automatically retry communication as many times as the number
set in this field.
b6
b5
b4
Number of retries
0
0
0
0
0
0
1
1
0
1
0
2
0
1
1
3
1
0
0
4
1
0
1
5
1
1
0
6
1
1
1
7
38
DATA SHEET S13990EJ2V0DS00