S1C63808 TECHNICAL MANUAL
EPSON
93
CHAPTER 4: PERIPHERAL CIRCUITS AND OPERATION (Serial Interface)
TXEN1: Serial interface 1 transmit enable register (FF66HD0)
TXEN2: Serial interface 2 transmit enable register (FF16HD0)
Sets the serial interface to the transmit enabled status.
When "1" is written: Transmit enabled
When "0" is written: Transmit disabled
Reading: Valid
When "1" is written to TXENx, the serial interface shifts to the transmit enabled status and shifts to the
transmit disabled status when "0" is written.
Set TXENx to "0" when making the initial settings of the serial interface and similar operations.
At initial reset, this register is set to "0".
TXTRG1: Serial interface 1 transmit trigger/status (FF66HD1)
TXTRG2: Serial interface 2 transmit trigger/status (FF16HD1)
Functions as the transmit start trigger and the operation status indicator (transmitting/stop status).
When "1" is read: During transmitting
When "0" is read: During stop
When "1" is written: Start transmitting
When "0" is written: Invalid
Starts transmitting when "1" is written to TXTRGx after writing the transmitting data.
TXTRGx can be read as the status. When set to "1", it indicates transmitting operation, and "0" indicates
transmitting stop.
At initial reset, TXTRGx is set to "0".
RXEN1: Serial interface 1 receive enable register (FF66HD2)
RXEN2: Serial interface 2 receive enable register (FF16HD2)
Sets the serial interface to the receive enabled status.
When "1" is written: Receive enabled
When "0" is written: Receive disabled
Reading: Valid
When "1" is written to RXENx, the serial interface shifts to the receive enabled status and shifts to the
receive disabled status when "0" is written.
Set RXENx to "0" when making the initial settings of the serial interface and similar operations.
At initial reset, this register is set to "0".
RXTRG1: Serial interface 1 receive trigger/status (FF66HD3)
RXTRG2: Serial interface 2 receive trigger/status (FF16HD3)
Functions as the receive start trigger or preparation for the following data receiving and the operation
status indicator (during receiving/during stop).
When "1" is read: During receiving
When "0" is read: During stop
When "1" is written: Start receiving/following data receiving preparation
When "0" is written: Invalid
RXTRGx has a slightly different operation in the clock synchronous system and the asynchronous system.
The RXTRGx in the clock synchronous system is used as the trigger for starting receive operation.
Write "1" into RXTRGx to start receiving at the point where the receive data has been read and the
following receive preparation has been done. (In the slave mode, SRDYx is asserted at the point where "1"
has been written into the RXTRGx.)