Intel® PXA26x Processor Family Developer’s Manual 9-27

Inter-Integrated Circuit Bus Interfac e Un i t
Table 9-12. I2C Status Register - ISR (Sheet 1 of 2)
Physical Address
4030_1698 I2C Status Register I2C
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Reserved
BED
SAD
GCAD
IRF
ITE
ALD
SSD
IBB
UB
ACKNAK
RWM
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
31:11 — Reserved
10 BED
BUS ERROR DETECTED:
0 – No error detected.
1 – The I2C unit sets this bit when it detects one of the following error conditions:
As a master transmitter, no ACK is detected on the interface after a byte is sent.
As a slave receiver, the I2C unit generates a NAK pulse.
NOTE: When an error occurs, I2C bus transactions continue. Software must ensure that
misplaced START and STOP conditions do not occur. See Section9.4.4,
“Arbitration”.
To clear this bit, write a 1 to it.
9SAD
SLAVE ADDRESS DETECTED:
0 – No slave address detected.
1 – I2C unit detected a 7-bit address that matches the general call address or ISAR. An
interrupt is signalled when the SADIE interrupt is set to a 1.
To clear this bit, write a 1 to it.
8GCAD
GENERAL CALL ADDRESS DETECTED:
0 – No general call address received.
1 – I2C unit received a general call address.
7IRF
IDBR RECEIVE FULL:
0 – The IDBR has not received a new data byte or the I2C unit is idle.
1 – The IDBR register received a new data byte from the I2C bus. An interrupt is signalled
when the IRFIE is set to a 1.
To clear this bit, write a 1 to it.
6ITE
IDBR TRANSMIT EMPTY:
0 – The data byte is still being transmitted.
1 – The I2C unit has finished transmitting a data byte on the I2C bus. An interrupt is
signalled when the ITEIE interrupt is set to 1.
To clear this bit, write a 1 to it.
5ALD
ARBITRATION LOSS DETECTED:
Used during multi-master operation.
0 – Cleared when arbitration is won or never took place.
1 – Set when the I2C unit loses arbitration.
To clear this bit, write a 1 to it.
4SSD
SLAVE STOP DETECTED:
0 – No STOP detected.
1 – Set when the I2C unit detects a STOP while in slave-receive or slave-transmit mode.
To clear this bit, write a 1 to it.
3IBB
I2C BUS BUSY:
0 – I2C bus is idle or the I2C unit is using the bus (i.e., unit busy).
1 – Set when the I2C bus is busy but the I2C unit is not involved in the transaction.