NEC V850/SB1 User Manual page 548

If the control bit received from the master unit is not as shown in Table 19-3, the unit locked by the master
unit rejects acknowledging the control bit, and does not output the acknowledge bit.
Note 1
Bit 3
0
0
0
Moreover, units for which lock is not set by the master unit reject acknowledgment and do not output an
acknowledge bit when the control data shown in Table 19-4 is acknowledged.
Bit 3
0
0
If one unit occupies the bus as the master, the value set to the IEBus control register (CDR) is output.
548
CHAPTER 19 IEBus CONTROLLER (V850/SB2)
Table 19-3. Control Field for Locked Slave Unit
Bit 2 Bit 1 Bit 0
0 0 0
1 0 0
0 0 1
Table 19-4. Control Field for Unlocked Slave Unit
Bit 2 Bit 1 Bit 0
1 0 0
1 0 1
Figure 19-4. Control Field
Control field
Control bit (4 bits)
MSB
User's Manual U13850EJ6V0UD
Function
Reads slave status
Reads lock address (lower 8 bits)
Reads lock address (higher 4 bits)
Function
Lock address read (lower 8 bits)
Lock address read (higher 4 bits)
Parity ACK
LSB