20 i
2
C MaSTeR (i2CM)
20-8
Seiko epson Corporation
S1C17624/604/622/602/621 TeChniCal Manual
i
2
C Master Control Register (i2CM_CTl)
Register name address
Bit
name
Function
Setting
init. R/W
Remarks
i
2
C Master Con-
trol Register
(i2CM_CTl)
0x4342
(16 bits)
D15–10 –
reserved
–
–
–
0 when being read.
D9
RBuSY
Receive busy flag
1 Busy
0 Idle
0
R
D8
TBuSY
Transmit busy flag
1 Busy
0 Idle
0
R
D7–5 –
reserved
–
–
–
0 when being read.
D4
nSeRM
Noise remove on/off
1 On
0 Off
0
R/W
D3–2 –
reserved
–
–
–
0 when being read.
D1
STP
Stop control
1 Stop
0 Ignored
0
R/W
D0
STRT
Start control
1 Start
0 Ignored
0
R/W
D[15:10] Reserved
D9
RBuSY: Receive Busy Flag Bit
Indicates the I2CM receiving status.
1 (R):
Operating
0 (R):
Standby (default)
RBUSY is set to 1 when the I2CM starts data receiving and is maintained at 1 while receiving is under-
way. It is cleared to 0 once reception is completed.
D8
TBuSY: Transmit Busy Flag Bit
Indicates the I2CM transmission status.
1 (R):
Operating
0 (R):
Standby (default)
TBUSY is set to 1 when the I2CM starts data transmission and is maintained at 1 while transmission is
underway. It is cleared to 0 once transmission is completed.
D[7:5]
Reserved
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.2 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 I
2
C bus SDA line
from Low to High with the SCL line maintaining at High. The I
2
C 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
automatically reset to 0 if the stop condition is generated.
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 I
2
C 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 I
2
C bus is busy.
STRT is automatically reset to 0 once the start condition or repeated start condition is generated. The
I
2
C bus subsequently becomes busy.