
16 I2C MASTER (I2CM)
16-8
Seiko Epson Corporation
S1C17705 TECHNICAL MANUAL
D4
NSERM: Noise Remove On/Off Bit
Turns the noise filter function on or off.
1 (R/W): On
0 (R/W): Off (default)
The I2CM module includes a function for filtering noise from the SDA0 and SCL0 pin input signals.
This function is enabled by setting NSERM to 1. Note that using this function requires setting the I2CM
clock (T16 Ch.3 output clock) frequency to 1/6 or less of PCLK.
D[3:2]
Reserved
D1
STP: Stop Control Bit
Generates the stop condition.
1 (R/W): Stop condition generated
0 (R/W): Ineffective (default)
By setting STP to 1, the I2CM module generates the stop condition by pulling up the I2C bus SDA line
from Low to High with the SCL line maintaining at High. The I2C bus subsequently becomes free. Note
that the stop condition will be generated only if STP is 1 and TXE/I2CM_DAT register, RXE/I2CM_
DAT register, and STRT are set to 0 when data transfer is completed (including ACK transfer). STP is
disabled if any of TXE, RXE, or STRT is 1. STP is automatically reset to 0 if the stop condition is gen-
erated.
D0
STRT: Start Control Bit
Generates the start condition.
1 (R/W): Start condition generated
0 (R/W): Ineffective (default)
By setting STRT to 1, the I2CM module generates the start condition by pulling down the I2C bus SDA
line to Low with SCL line maintaining at High.
The repeated start condition can be generated by setting STRT to 1 when the I2C bus is busy.
STRT is automatically reset to 0 once the start condition or repeated start condition is generated. The
I2C bus subsequently becomes busy.
I2C Master Data Register (I2CM_DAT)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
I2C Master Data
Register
(I2CM_DAT)
0x4344
(16 bits)
D15–12 –
reserved
–
0 when being read.
D11
RBRDY
Receive buffer ready flag
1 Ready
0 Empty
0
R
D10
RXE
Receive execution
1 Receive
0 Ignored
0
R/W
D9
TXE
Transmit execution
1 Transmit
0 Ignored
0
R/W
D8
RTACK
Receive/transmit ACK
1 Error
0 ACK
0
R/W
D7–0 RTDT[7:0]
Receive/transmit data
RTDT7 = MSB
RTDT0 = LSB
0x0 to 0xff
0x0 R/W
D[15:12] Reserved
D11
RBRDY: Receive Buffer Ready Flag Bit
Indicates the receive buffer status.
1 (R):
Receive data exists
0 (R):
No receive data (default)
The RBRDY flag becomes 1 when the data received in the shift register is loaded to RTDT[7:0] and
reverts to 0 when the receive data is read out from RTDT[7:0]. Interrupts can also be generated once the
flag value becomes 1.
Note: Use the RBUSY flag when awaiting reception using polling. The RBRDY flag cannot be used
to await reception with polling. For more information on awaiting reception control procedures
using polling, refer to “Data reception control” in Section 16.5.