Remote-processing RPC-52 Manuel d'utilisateur télécharger pdf (Page 11)

CHAPTER 4 SERIAL PORTS

Page 9

Figure 4-1 Serial port and jumper locations

DESCRIPTION

The RPC -52 has two serial ports that can be used for

interfacing to a printer, terminal, RS-485 network, or

other ser ial devices. This chapte r descr ibes their

characteristics and how to use them. Frequent

references are made to commands listed in the BASIC-52

Programming Manual or RPBA SIC-52 Software

Supplement in this manual. Please refer to these

manuals for m ore inform ation about these comm ands.

Serial por ts are num bered C OM 0 and CO M1. COM 0 is

RS232 only and is used for progr am development.

During r un time, it can be used for other functions.

COM1 is a general purpose port and can be used as

either RS-232 or RS-422/485.

Each port has a 256 character interrupt driven input and

output buffer. This allows characters to be sent out

(using PRINT) without slowing down program

execution. However, if the PRINT buffer fills, program

execution is suspended until all characters are in the

buffer. Both ports have a 256 character input buffer.

When more than 256 char acters are r eceived, excess

ones are ignored.

Your circuit board may have COM0 and COM1 marked

as COM1 and COM2. If this is the case, the silkscreen

is wrong and this manual should be followed.

COM0 SERIAL PORT

This port uses a VTC-9F serial cable to connect external

serial devices to the por t. The cable consists of a 10 pin

IDC connector wired one-to-one to a DB-9 connector.

Line 10 is sim ply cut off. The pin out is designed so it

plugs directly into the 9 pin serial port connector on a

PC.

COM 0 does not use hardware handshake lines. T he

CTS line is pulled high in case external equipment uses

this line.

This port is normally used for program ming. D uring

run time it may be used as a general purpose seria l port.

When used for programming or with the INPUT

statement, it will accept ASCII character values from 0

to 127. When used with the GET function, it will return

ASCII values from 0 to 255.

COM1 SERIAL PORT

COM 1 is either an RS-232 or RS-422/ 485 port. A

VTC-9F serial cable, descr ibed above, is used for RS-

232 level communications. RS-485 is from screw

terminals. COM 1 is identical to COM0 except that

COM 1 has 2 hardware handshaking lines, C TS and

RTS. When RTS goes low, the RPC-52 is held off from

transmitting out COM1. The status of this port is read

by the LINE B statement. The example below returns

the status of the RTS line:

100 B = LINEB(2,5).AND.64

If B = 64, transmission is held off.

The CTS line may be set high or low to hold off

comm unication. Line 400 sets CTS high and 500 sets it

low, or to hold off.

400 LINEB2,2,0A5H

500 LINEB2,2,0B5H

Jumper W1 determines if COM 1 receive is RS-232 or

RS-422/485.

[1-2] RS-485

[2-3] RS-232 (default)

COM1 default is RS-232. Use the CONFIG BAUD

statement to set it to RS-422 or RS-485. When set to

RS-422, the transmitter is always on. RS-485 mode

turns on the transmitter only when sending.

RS-422/485 Termination network

When the RPC-52 is the last physical unit on a network

(RS-485), or it is the only unit (RS-422), the receiver

must be terminated to prevent ringing. Jumper block

W2 installs or removes this network. Set W2 according

to the table below:

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 35 36

Commentaires sur ces manuels

Pas de commentaire

Remote-processing RPC-52 Manuel d'utilisateur Page 11

Commentaires sur ces manuels

Produits connexes et manuels pour Ordinateurs Remote-processing RPC-52