Information

I2Cx_S field descriptions (continued)
Field Description
• Any nonzero calling address is received that matches the address in the RA register.
• The RMEN bit is set and the calling address is within the range of values of the A1 and RA registers.
Writing the C1 register with any value clears this bit.
0 Not addressed
1 Addressed as a slave
2
SRW
Slave Read/Write
When addressed as a slave, SRW indicates the value of the R/W command bit of the calling address sent
to the master.
0 Slave receive, master writing to slave
1 Slave transmit, master reading from slave
1
IICIF
Interrupt Flag
This bit sets when an interrupt is pending. This bit must be cleared by software by writing a 1 to it, such as
in the interrupt routine. One of the following events can set this bit:
• One byte transfer, including ACK/NACK bit, completes if FACK = 0. An ACK or NACK is sent on the
bus by writing 0 or 1 to TXAK after this bit is set in receive mode.
• One byte transfer, excluding ACK/NACK bit, completes if FACK = 1.
• Match of slave address to calling address including primary slave address, range slave address,
alert response address, second slave address, or general call address.
• Arbitration lost
• In SMBus mode, any timeouts except SCL and SDA high timeouts
0 No interrupt pending
1 Interrupt pending
0
RXAK
Receive Acknowledge
0 Acknowledge signal was received after the completion of one byte of data transmission on the bus
1 No acknowledge signal detected
47.3.5 I2C Data I/O register (I2Cx_D)
Address: Base address + 4h offset
Bit 7 6 5 4 3 2 1 0
Read
DATA
Write
Reset
0 0 0 0 0 0 0 0
I2Cx_D field descriptions
Field Description
7–0
DATA
Data
In master transmit mode, when data is written to this register, a data transfer is initiated. The most
significant bit is sent first. In master receive mode, reading this register initiates receiving of the next byte
of data.
Chapter 47 Inter-Integrated Circuit (I2C)
K20 Sub-Family Reference Manual, Rev. 1.1, Dec 2012
Freescale Semiconductor, Inc.
Preliminary
1241
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