13 I
2
C (I2C)
S1C17M12/M13 TECHNICAL MANUAL
Seiko Epson Corporation
13-19
(Rev. 1.2)
I2C Ch.
n
Control Register
Register name
Bit
Bit name
Initial
Reset
R/W
Remarks
I2CnCTL
15–8 –
0x00
–
R
–
7–6 –
0x0
–
R
5
MST
0
H0
R/W
4
TXNACK
0
H0/S0
R/W
3
TXSTOP
0
H0/S0
R/W
2
TXSTART
0
H0/S0
R/W
1
SFTRST
0
H0
R/W
0
MODEN
0
H0
R/W
Bits 15–6 Reserved
Bit 5
MST
This bit selects the I2C Ch.
n
operating mode.
1 (R/W): Master mode
0 (R/W): Slave mode
Bit 4
TXNACK
This bit issues a request for sending a NACK at the next responding.
1 (W):
Issue a NACK.
0 (W):
Ineffective
1 (R):
On standby or during sending a NACK
0 (R):
NACK has been sent.
This bit is automatically cleared after a NACK has been sent.
Bit 3
TXSTOP
This bit issues a STOP condition in master mode. This bit is ineffective in slave mode.
1 (W):
Issue a STOP condition.
0 (W):
Ineffective
1 (R):
On standby or during generating a STOP condition
0 (R):
STOP condition has been generated.
This bit is automatically cleared when the bus free time (t
BUF
defined in the I
2
C Specifications) has
elapsed after the STOP condition has been generated.
Bit 2
TXSTART
This bit issues a START condition in master mode. This bit is ineffective in slave mode.
1 (W):
Issue a START condition.
0 (W):
Ineffective
1 (R):
On standby or during generating a START condition
0 (R):
START condition has been generated.
This bit is automatically cleared when a START condition has been generated.
Bit 1
SFTRST
This bit issues software reset to the I2C.
1 (W):
Issue software reset
0 (W):
Ineffective
1 (R):
Software reset is executing.
0 (R):
Software reset has finished. (During normal operation)
Setting this bit resets the I2C transmit/receive control circuit and interrupt flags. This bit is automati-
cally cleared after the reset processing has finished.
Bit 0
MODEN
This bit enables the I2C operations.
1 (R/W): Enable I2C operations (The operating clock is supplied.)
0 (R/W): Disable I2C operations (The operating clock is stopped.)