![NEC V850/SC1 User Manual Download Page 531](http://html.mh-extra.com/html/nec/v850-sc1/v850-sc1_user-manual_248178531.webp)
CHAPTER 18 IEBus CONTROLLER (V850/SC2)
User’s Manual U15109EJ3V0UD
529
After reset: 01H
R/W
Address: FFFFF3E8H
7
6
5
4
3
2
1
0
CDR
0
0
0
0
MOD
SELCL2
SELCL1
SELCL0
MOD
SELCL2
SELCL1
SELCL0
Function
0
0
0
0
Reads slave status
0
0
0
1
Undefined
0
0
1
0
Undefined
0
0
1
1
Reads data and locks
0
1
0
0
Reads lock address (lower 8 bits)
0
1
0
1
Reads lock address (lower 4 bits)
0
1
1
0
Reads slave status and unlocks
0
1
1
1
Reads data
1
0
0
0
Undefined
1
0
0
1
Undefined
1
0
1
0
Writes command and locks
1
0
1
1
Writes data and locks
1
1
0
0
Undefined
1
1
0
1
Undefined
1
1
1
0
Writes command
1
1
1
1
Writes data
Cautions 1. Because the slave unit must judge whether the received data is a “command” or
“data”, it must read the value of this register after completing communication.
2. If the master unit sets an undefined value, NACK is returned from the slave unit, and
communication is aborted. During broadcast communication, however, the master
unit continues communication without recognizing ACK/NACK; therefore, make sure
not to set an undefined value to this register during broadcast communication.
3. In the case of defeat in a bus conflict and a slave status request is received from the
unit that won, the telegraph length register (DLR) is fixed to “01H”. Therefore, when a
re-request of the master follows, the appointed telegraph length must be set to DLR.