Inter-Integrated Circuit Controller
7-70
Bus Busy (BB)
This read-only bit (12) indicates the state of the serial bus.
-
In the slave mode, on reception of a start condition, the device sets BB to
1. BB is clear to 0 after reception of a stop condition.
-
In the master mode, the software controls BB. To start a transmission with
a start condition, MST, TRX, and STT must be set to 1. To end a transmis-
sion with a stop condition, STP must be set to 1. When BB = 1 and STT
is set to a 1, a restart condition is generated.
J
0: Bus is free.
J
1: Bus is occupied.
Value after reset is low.
Receive Overrun (ROVR)
Receive mode only.
This read-only bit (11) indicates whether the receiver has experienced over-
run. Overrun occurs when the receive shift register (ICRSR) is full and the
receive FIFO is full. An overrun condition does not result in a data loss, the
peripheral is just holding the bus (low on SCL) and prevent others bytes from
being received.
-
ROVR is set to 1 when the I
2
C has recognized an overrun.
-
ROVR is clear when reading the I2C_DATA register or resetting the I
2
C
(I2C_EN=0).
J
0: Normal operation
J
1: Receiver overrun
Value after reset is low.
Transmit Underflow (XUDF)
This read-only bit (10) indicates whether the transmitter has experienced
underflow.
-
In the master transmit mode, underflow occurs when the transmit shift reg-
ister (ICXSR) is empty, the transmit FIFO is empty, and there are still bytes
to transmit (DCOUNT
≠
0).
-
In the slave transmit mode, underflow occurs when the transmit shift regis-
ter (ICXSR) is empty, the transmit FIFO is empty, and there are still bytes
to transmit (read request from external I
2
C master).