- 47 -
RS-232C control
Connect a male (D-Sub 9 Pin) to female (D-Sub 9 Pin)
straight cable for RS-232C external control by host equip-
ment.
• The RS-232C host can control functions of the
PMD570 externally
• The PMD570 automatically transmits status data when
status is changed.
• The PMD570 will respond to status requests by
transmitting the associated status data.
RS-232C specifications:
Connector pin assignment
6 7 8 9
1 2 3 4 5
pin
1
2
3
4
5
6
7
8
9
use
NC
TX
RX
NC
GND
NC
RTS
CTS
NC
PMD570
Not Connected
Transmit Data
Receive Data
Not Connected
Ground
Not connected
RTS receive
CTS send
Not Connected
D-Sub 9 pin
(male)
Typical Host
Not Connected
Receive Data
Transmit Data
Not Connected
Ground
Not connected
RTS send
CTS receive
Not Connected
D-Sub 9 pin
(female)
cable
connector
Cable
Baud rate
Data bits
Parity bit
Stop bit
Flow control
Straight cable
9600 bps
8 bits
None
1 bit
CTS/RTS Hardware Flow
Physical specifications
Typical Host
RTS send
PMD570
CTS out
Not Busy
(Normal)
Busy
H
L
H
L
Timing chart
Flow control and timing
CTS/RTS hardware flow control
1. The host requests data by setting RTS to L.
2. Upon data request by CTS, the PMD570 responds
by setting RTS to H if not busy.
3. The host checks if CTS is H and stats data output
on TxD.
4. When data output finishes, the host sets RTS to H.
5. The PMD570 checks if CTS is H and sets RTS to L.
Header Addr Command code
Return
@
1
0Dh
Received okay and error codes
OK (data receive successful) (ACK): 06h
Error (data receive error) (NACK):
15h
Normal Return
Error Return
OK
06h
ERR
15h
Notes:
The receiving side ignores data received prior to "@".
If code data is received without receiving "@", the
data receive error code will be returned.
The tolerance for send/receive clock error is
±
10%.
For sending a command, wait more than 20ms after
reception of a response (OK, ERR or Status).
Reception of 0Dh or timeout is used to determine the
end of a command. Timeout occurs 1 second after the
reception of the last byte.
RTS
RxD
TxD
CTS
Host
CTS
RTS
PMD570
RxD
TxD
Command format
Start character:
@
End character:
0Dh
Basic format
