UPSD33XX Datasheet, PDF (103/231 Pages) STMicroelectronics – Fast 8032 MCU with Programmable Logic

uPSD33xx
Table 52. S1STA: I²C Interface Status Register (SFR DDh, reset value 00h)
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
GC
STOP
INTR
TX_MODE BBUSY
BLOST ACK_RESP
SLV
Details
Bit
Symbol
R/W
Function
General Call flag
7
GC
R
GC = 1 if the General Call address of 00h was received when SIOE is in
Slave mode, and GC is cleared by a START or STOP condition on the
bus. If the SIOE is in Master mode when GC = 1, the Bus Lost condition
exists, and BLOST = 1.
STOP flag
6
STOP
R
STOP = 1 while SIOE detects a STOP condition on the bus when in
Master or Slave mode.
Interrupt flag
5
INTR
R,W
INTR is set to 1 by any of the five I²C interrupt conditions listed above.
INTR must be cleared by firmware.
Transmission Mode flag
4
TX_MODE
R
TX_MODE = 1 whenever the SIOE is in Master-Transmitter or Slave-
Transmitter mode. TX_MODE = 0 when SIOE is in any receiver mode.
Bus Busy flag
3
BBUSY
R
BBUSY = 1 when the I²C bus is in use. BBUSY is set by the SIOE when
a START condition exists on the bus and BBUSY is cleared by a STOP
condition.
Bus Lost flag
2
BLOST
R
BLOST is set when the SIOE is in Master mode and it looses the
arbitration process to another Master device on the bus.
Not Acknowledge Response flag
While SIOE is in Transmitter mode:
– After SIOE sends a byte, ACK_RESP = 1 whenever the external I²C
device receives the byte, but that device does NOT assert an
ackowledge signal (external device asserted a high on SDA during
the acknowledge bit-time).
1
ACK_RESP
R
– After SIOE sends a byte, ACK_RESP = 0 whenever the external I²C
device receives the byte, and that device DOES assert an
ackowledge signal (external device drove a low on SDA during the
acknowledge bit-time)
Note: If SIOE is in Master-Transmitter mode, and ACK_RESP = 1 due to
a Slave-Transmitter not sending an Acknowledge, a STOP condition will
not automatically be generated by the SIOE. The STOP condition must
be generated with S1CON.STO = 1.
Slave Mode flag
0
SLV
R
SLV = 1 when the SIOE is in Slave mode. SLV = 0 when the SIOE is in
Master mode (default).
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