CHAPTER 19 IEBus CONTROLLER (V850/SB2)
User’s Manual U13850EJ4V0UM
476
(11)IEBus success count register (SCR)
The IEBus success count register (SCR) indicates the number of remaining communication bytes.
This register reads the count value of the counter that decrements the value set by the telegraph length
register by ACK in the data field. When the count value has reached “00H”, the communication end flag
(ENDTRNS) of the IEBus interrupt status register (ISR) is set.
Figure 19-26. IEBus Success Count Register (SCR) Format
After reset: 01H
R
Address: FFFFF3F4H
7
6
5
4
3
2
1
0
SCR
Bit
7
6
5
4
3
2
1
0
Setting
value
Remaining number of
communication data bytes
0
0
0
0
0
0
0
1
01H
1 byte
0
0
0
0
0
0
1
0
02H
2 bytes
:
:
:
:
:
:
:
:
:
:
0
0
1
0
0
0
0
0
20H
32 bytes
:
:
:
:
:
:
:
:
:
:
1
1
1
1
1
1
1
1
FFH
255 bytes
0
0
0
0
0
0
0
0
00H
0 byte (end of communication)
or 256 bytes
Note
Note
The actual hard counter consists of 9 bits. When “00H” is read, it cannot be judged whether the
remaining number of communication data bytes is 0 (end of communication) or 256. Therefore, either
the communication end flag is used, or if “00H” is read when the first interrupt occurs at the beginning
of communication, the remaining number of communication data bytes is judged to be 256.
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