16
2) Serial Interface
①
Specifications
Data Input : RS-232C
Hand Shake : DTR, RXD, Level TXD, GND
Synchronism Type : Start/stop synchronism type
Baud Rate : 2400, 4800, 960, 19200 bps
Start Bit : 1 bit
Data bit : 8 bits ( fixed )
Parity Bit : none
Stop Bit : 1 bit ( fixed )
②
Signal Timing
When AI-220 receives 1 line of data, it starts printing process.
When 1/2 bit passed from the fall edge of start bit of Receive Data (RXD ) “ from
Mark to Space status”, it reads the status again, and if it is in Space status, it is
recognized as Start bit to start serial input. If it gets Stop bit “Mark status”, it
starts receiving the next data. When it receives 1 line of data, it starts printing
process.
Even during printing process, it can receive data.
When the data inside the input buffer exceeds 15bytes, it makes DTR signal
“ Mark status” demanding to stop data transmission from the host device
temporarily. Then printing process goes on, and when the data quantify becomes
10K bytes or less, it makes DTR signal “ Space status” demanding to re-start
transmission.
③
Timing Chart
Starts Printing Process
1 line of Data
DTR
RXD
Stop bit
Start bit
