Table 13.4.7C Meaning Of Slave Status - Fujitsu F2MC-16LX MB90580 Series Hardware Manual

(1) Slave status (SSR) read (control bits: 0H, 6H)
By reading the slave status, the master can understand why the slave has not returned the acknowledge
bit (ACK). The slave status is determined in respect to the result of the last communication performed by
the slave unit. Moreover all slaves can supply the information of slave status as configured below:
Slave Status
Bit 7
Bit
Bit 0
Note1
Bit 1
Note2
Bit 2
Bit 3
Bit 4
Note3
Bit 5
Bit 6
Bit 7
Note1: The slave transmit buffer is the buffer accessed when data is read (control bits: 3H,
7H). This buffer is same as the write data buffer (WDB).
Note2: The slave receive buffer is the buffer accessed when data is written (control bits: 8H,
AH, BH, EH, FH). This buffer is same as the read data buffer (RDB).
Note3: This bit can be selected by the PCOM bit in command register (CMRH).
Note4: For MB90580 series, 10 is fixed.
(2) Data/command transfer (control bits: read (3H, 7H), write (AH, BH, EH, FH))
If the control bits indicate data read (3H, 7H), the data in the data buffer of the slave is read by the master.
If the control bits indicate data write (BH, FH) or command write (AH, EH), the data received by the slave is
processed in accordance with the operation regulation of that slave.
Note1: The data or command can be selected with the user's own decision in the corre-
sponding system.
Note2: The slave is also locked when control bits are 3H, AH and BH.
MB90580 Series
MSB
Bit 5
Bit 6

Table 13.4.7c Meaning of Slave Status

Value
0
1
0
1
0
1
0
0
1
0
00 Mode 0
01 Mode 1
10 Mode 2
11 Prohibited
Bit 4 Bit 3 Bit 2
Meaning
Slave transmit buffer is empty
Slave transmit buffer is not empty
Slave receive buffer is not full
Slave receive buffer is full
Unit is not locked
Unit is locked
Fixed to '0'
Slave transmission is stopped
Slave transmission is enabled
Fixed to '0'
Indicates the highest mode that is
supported by the unit
13.4 IEBus Communication Protocol
LSB
Bit 1 Bit 0
Note 4
Chapter 13: IE Bus 171