Datasheet
I2C_C1 field descriptions (continued)
Field Description
2
RSTA
Repeat START
Writing a one to this bit generates a repeated START condition provided it is the current master. This bit
will always be read as zero. Attempting a repeat at the wrong time results in loss of arbitration.
1
WUEN
Wakeup Enable
The I2C module can wake the MCU from low power mode with no peripheral bus running when slave
address matching occurs.
0 Normal operation. No interrupt generated when address matching in low power mode.
1 Enables the wakeup function in low power mode.
0
Reserved
This field is reserved.
This read-only field is reserved and always has the value 0.
18.3.4 I2C Status register (I2C_S)
Address: 3070h base + 3h offset = 3073h
Bit 7 6 5 4 3 2 1 0
Read TCF
IAAS
BUSY ARBL
RAM
SRW IICIF RXAK
Write w1c w1c
Reset
1 0 0 0 0 0 0 0
I2C_S field descriptions
Field Description
7
TCF
Transfer Complete Flag
This bit sets on the completion of a byte and acknowledge bit transfer. This bit is valid only during or
immediately following a transfer to or from the I2C module. The TCF bit is cleared by reading the I2C data
register in receive mode or by writing to the I2C data register in transmit mode.
0 Transfer in progress
1 Transfer complete
6
IAAS
Addressed As A Slave
This bit is set by one of the following conditions:
• The calling address matches the programmed slave primary address in the A1 register or range
address in the RA register (which must be set to a nonzero value).
• GCAEN is set and a general call is received.
• SIICAEN is set and the calling address matches the second programmed slave address.
• ALERTEN is set and an SMBus alert response address is received
• RMEN is set and an address is received that is within the range between the values of the A1 and
RA registers.
This bit sets before the ACK bit. The CPU must check the SRW bit and set TX/RX accordingly. Writing the
C1 register with any value clears this bit.
Table continues on the next page...
Chapter 18 Inter-Integrated Circuit (I2C)
MC9S08PA60 Reference Manual, Rev. 1, 9/2012
Freescale Semiconductor, Inc. 499