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3. Interfaces
3.1 Serial interface
1) Synchronization
2) Handshake
3) Transfer speed
4) 1 word consists of :
Start bit
Data bit
Parity bit
Stop bit
5) Signal polarity
RS-232C
Mark
: Theory "1" (-3V~-12V)
Space : Theory "0" (+3V~+12V)
6) Reception data (RXD signal)
Mark
: 1
Space : 0
7) Reception control (RTS signal)
RS-232C
Mark
: Data transmission not available
Space
: Data transmission available
Busy status (marked) will be :
At reception buffer full
During hardware being reset after power is set on
During software being reset
At self-print
During firmware being rewritten
8) Transmission data (TXD signal)
RS-232C
Mark
: 1
Space : 0
9) Transmission control (CTS signal)
The host indicates that data reception is available.
3.2 Input/output circuit
Serial interface signal
It is structured by the driver and receiver in accordance with RS-232C.
TXD
RXD
RTS
CTS
The signal level: Mark = -3 ~ -15V, Logic "1" Off
: Not synchronized
: RTS/CTS control
: 19200bps, 38400bps
: 1 bit fixed
: 8 bits fixed
: No parity. Fixed.
: 2 bits fixed.
HIN202CA
Space = +3 ~ +15V, Logic "0" On
TO CPU circuit
6
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