Epson S1C17001 Technical Manual page 275

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20 I C
D[7:0] RTDT[7:0]: Receive/Transmit Data Bits
When sending data
Set the transmission data. (Default: 0x0)
Data transmission is started by setting TXE (D9) to 1. If a slave address or data is currently being trans-
mitted, transmission begins once the previous transmission is completed. Serial converted data is output
from the SDA pin with MSB leading and bits set to 0 as Low level.
A transmit buffer empty interrupt factor is generated as soon as the data written to this register is trans-
ferred to the shift register, after which the subsequent transmission data can be written.
When receiving data
Read the receive data. (Default: 0x0)
Data receipt is started by setting RXE (D10) to 1. If a slave address is currently being transmitted or
data is currently being received, the new receipt starts once the previous data has been transferred. The
RBRDY flag (D11) is set and a receive buffer full interrupt factor generated as soon as receipt is com-
plete and the shift register data is transferred to this register. Data can then be read until the subsequent
data has been received. If the subsequent data is received before this register is read out, the contents
are overwritten by the most recent received data.
Serial data input from the SDA pin with MSB leading is converted to parallel, with the High level bit
set to 1 and the Low level bit set to 0, then loaded to this register.
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S1C17001 TECHNICAL MANUAL