19 UNIVERSAL SERIAL INTERFACE WITH LCD INTERFACE (USIL)
S1C33L26 TECHNICAL MANUAL
Seiko Epson Corporation
19-39
SEIF is reset by writing 1. To reset an overrun error, write 1 to SEIF and then read the receive data buf-
fer (USIL_RD register) twice. The procedure that writes 1 to SEIF and reads USIL_RD register twice
can be reversed.
D1
SRDIF: Receive Buffer Full Flag Bit
Indicates the receive data buffer status.
1 (R):
Data full
0 (R):
No data (default)
1 (W):
Reset to 0
0 (W):
Ignored
SRDIF is set to 1 when data received in the shift register is sent to the receive data buffer (when receiv-
ing is completed), indicating that the data can be read. At the same time a receive buffer full interrupt
request is sent to the ITC if SRDIE/USIL_SIE register is 1. SRDIF is reset by writing 1.
D0
STDIF: Transmit Buffer Empty Flag Bit
Indicates the transmit data buffer status.
1 (R):
Empty
0 (R):
Data exists (default)
1 (W):
Reset to 0
0 (W):
Ignored
STDIF is set to 1 when the transmit data written to the transmit data buffer is transferred to the shift
register (when transmission starts), indicating that the next transmit data can be written to. At the same
time a transmit buffer empty interrupt request is sent to the ITC if STDIE/USIL_SIE register is 1.
STDIF is reset by writing 1.
USIL I
2
C Master Mode Trigger Register (USIL_IMTG)
Register name Address
Bit
Name
Function
Setting
Init. R/W
Remarks
USIL I
2
C Master
Mode Trigger
Register
(USIL_IMTG)
0x300660
(8 bits)
D7–5 –
reserved
–
–
–
0 when being read.
D4
IMTG
I
2
C master operation trigger
1 Trigger
0 Ignored
0
W
1 Waiting
0 Finished
R
D3
–
reserved
–
–
–
0 when being read.
D2–0 IMTGMOD
[2:0]
I
2
C master trigger mode select
IMTGMOD[2:0] Trigger mode
0x0 R/W
0x7
0x6
0x5
0x4
0x3
0x2
0x1
0x0
reserved
Receive ACK/NAK
Transmit NAK
Transmit ACK
Receive data
Transmit data
Stop condition
Start condition
Note: This register is effective only in I
2
C master mode. Configure USIL to I
2
C master mode before this
register can be used.
D[7:5]
Reserved
D4
IMTG: I
2
C Master Operation Trigger Bit
Starts an I
2
C master operation.
1 (W):
Trigger
0 (W):
Ignored
1 (R):
Waiting for starting operation
0 (R):
Trigger has finished (default)
Select an I
2
C master operation using IMTGMOD[2:0] and write 1 to IMTG as the trigger. The I
2
C con-
troller controls the I
2
C bus to generate the specified operating status.
D3
Reserved
D[2:0]
IMTGMOD[2:0]: I
2
C Master Trigger Mode Select Bits
Selects an I
2
C master operation.