Table 14-12. I2C Status Register (I2CSTR) Field Descriptions (continued)
Bit
Field
Type
Reset
Description
1
NACK
R/W1C
0h
No-acknowledgment interrupt flag bit.
NACK applies when the I2C module is a master transmitter. NACK
indicates whether the I2C module has detected an acknowledge bit
(ACK) or a noacknowledge bit (NACK) from the slave receiver. The
CPU can poll NACK or use the NACK interrupt request.
Reset type: SYSRSn
0h (R/W) = ACK received/NACK not received. This bit is cleared by
any one of the following events:
- An acknowledge bit (ACK) has been sent by the slave receiver.
- NACK is manually cleared. To clear this bit, write a 1 to it.
- The CPU reads the interrupt source register (I2CISRC) and the
register contains the code for a NACK interrupt. Debug probe reads
of the I2CISRC do not affect this bit.
- The I2C module is reset.
1h (R/W) = NACK bit received. The hardware detects that a no-
acknowledge (NACK) bit has been received.
Note: While the I2C module performs a general call transfer, NACK
is 1, even if one or more slaves send acknowledgment.
0
ARBL
R/W1C
0h
Arbitration-lost interrupt flag bit (only applicable when the I2C module
is a master-transmitter).
ARBL primarily indicates when the I2C module has lost an arbitration
contest with another master-transmitter. The CPU can poll ARBL or
use the ARBL interrupt request.
Reset type: SYSRSn
0h (R/W) = Arbitration not lost. AL is cleared by any one of the
following events:
- AL is manually cleared. To clear this bit, write a 1 to it.
- The CPU reads the interrupt source register (I2CISRC) and the
register contains the code for an
AL interrupt. Debug probe reads of the I2CISRC do not affect this bit.
- The I2C module is reset.
1h (R/W) = Arbitration lost. AL is set by any one of the following
events:
- The I2C module senses that it has lost an arbitration with two
or more competing transmitters that started a transmission almost
simultaneously.
- The I2C module attempts to start a transfer while the BB (bus busy)
bit is set to 1.
When AL becomes 1, the MST and STP bits of I2CMDR are cleared,
and the I2C module becomes a slave-receiver.
Inter-Integrated Circuit Module (I2C)
SPRUH18I – JANUARY 2011 – REVISED JUNE 2022
TMS320x2806x Microcontrollers
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Содержание TMS320 2806 Series
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