
FUJITSU LIMITED
PRELIMINARY and CONFIDENTIAL
MB86277 MINT
Graphics Controller
219
Specifications Rev. 1.0
11.2.15 I2C registers
BSR (Bus Status Register)
Register
address
I2C Base Address + 000h
Bit No
7
6
5
4
3
2
1
0
Bit field name
BB
RSC
AL
LRB
TRX
AAS
GCA
FBT
R/W
R
Default
0
All bits on this register are cleared while bit EN on CCR register is “0”.
Bit7
BB (Bus Busy)
Indicate state of I2C-bus
0: STOP condition was detected.
1: START condition (The bus is in use.) was detected.
Bit6
RSC (Repeated START Condition)
Indicate repeated START condition
This bit is cleared by writing “0” to INT bit, the case of not addressed in a slave
mode, the detection of START condition under bus stop, and the detection of STOP
condition.
0: Repeated START condition was not detected.
1: START condition was detected again while the bus was in use.
Bit5
AL(Arbitration Lost)
Detect Arbitration lost
This bit is cleared by writing “0” to INT bit.
0: Arbitration lost was not detected.
1: Arbitration occurred during master transmission, or “1” writing was performed to
MSS bit while other systems were using the bus.
Bit4
LRB (Last Received Bit)
Store Acknowledge
This bit is cleared by detection of START condition or STOP condition.
Bit3
TRX (Transmit / Receive)
Indicate data receipt and data transmission.
0: receipt
1: transmission
Bit2
AAS (Address As Slave)
Detect addressing
This bit is cleared by detection of START condition or STOP condition.
0: Addressing was not performed in a slave mode.
1: Addressing was performed in a slave mode.
Bit1
GCA (General Call Address)
Detect general call address (00h)
This bit is cleared by detection of START condition or STOP condition.
0: General call address was not received in a slave mode.
1: General call address wad received in a slave mode.
Bit0
FBT (First Byte Transfer)
Detect the 1st byte
Even if this bit is set to “1” by detection of START condition, it is cleared by writing
“0” on INT bit or by not being addressed in a slave mode.
0: Received data is not the 1st byte.
1: Received data is the 1st byte (address data).