Remote-processing RPC-210 Manual de usuario descargar pdf (Pagina 20)

SERIAL & SPI PORTS BASIC SECTION 4

Page 4-2

Figure 4-2 COM 1 jumper locations

Be aware that when continuously printing at this rate,

interrupt processing overhead becomes significant.

About 20% of the time is spent servicing the interr upt.

This will cause the main program to slow down by that

amount.

COM1 SERIAL PORT

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

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

232 level communications. RS-485 is from header J6.

NOTE: Some functions of COM 1 may be used with

interrupt 0 (ITR 0) or the hardware counter

(CTS frequency output). When this is the case,

then COM 1 may not be used.

NOTE: Make sure J7-3 is jumpered to J7-5. This

enables COM1 interr upts. If this jumper is

removed, the serial port will not work. Also,

CON FIG BAUD must be executed pr ior to

using COM 1 serial port. This statement

enables inter rupts

Jumper W5 determines if COM 1 receive is RS-232 or

RS-422/485.

W5[1-2] RS-232 (default)

W5[2-3] RS-422/485

COM 1 is set to RS-232 at the factory. Use CONFIG

BAUD to set the software 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.

CONF IG BAUD also determines the baud rate.

Interrupt 0 is turned off and pointers reset when

RPBASIC-52 is in the immediate mode (program not

running). It is turned on only when a CONFIG BAUD

or ON ITR comma nd is executed and the BASIC is

running. What this means is you can not do a PRINT

#1, nor r ecover any information sent to COM 1 in the

immediate mode.

CTS and RTS

Nomenclature for CTS and RTS, like Txd and Rxd,

changes depending upon which end of the device you are

referencing. For purposes below, RTS is an input to the

RPC -210 and C TS is an outp ut.

CTS and RTS lines are not automatically supported by

RPBASIC-52. These lines can be read and controlled as

shown in sample pr ograms.

WRCTS1.BAS toggles the CTS output line to the device.

The CTS line is used to control sending by an external

device. A high usually enables sending while a low

(negative voltage) holds off a device. The RP C-210

buffers up to 256 characters. If you have received a

message and know it will take time to process the data,

you may want to hold off the sender until the data is

processed.

RDRTS1.BAS reads the current status of the RTS input

line. This line is read to determine if the current device

wants the RPC-210 to start or stop sending data. M any

devices buffer a certain amount of data. If the

transmission rate is faster than the device can handle it

(as in a printer or cell modem), the RPC-210 may be

requested to stop sending for a while. Keep in mind that

while you may stop using the PRINT #1 command, the

transmitter on the RPC-210 may still send data until the

buffer is empty. If this is a problem, send out data in

smaller chunks and check the RTS input frequently.

RPBASIC-52 Programming Manual difference

CONFIG BAUD 1,0 does not output 57,600. W hen a

baud code 0 is entered, the rate will be 38,400.

Be aware that when contentiously printing at this rate,

interrupt processing overhead becomes significant.

About 25% of the time is spent servicing the interr upt.

This will cause the main program to slow down by that

amount.

NOTE: When contentiously printing (minutes at a time)

at 38,400, tick timer s slow dow n. T his is

because the interrupt overhead processing time

is so great, some 10 mSec tick interrupts are

missed. Over a period of 5 minutes, 1 second

of tick time accuracy is lost. The real time

clock is not affected. Tick timer accuracy is not

affected when operating at 19,200 or slower

baud.

1 2 ... 15 16 17 18 19 20 21 22 23 24 25 ... 59 60

Comentarios a estos manuales

Sin comentarios

Remote-processing RPC-210 Manual de usuario Pagina 20

Comentarios a estos manuales

Relacionado con productos y manuales para Ordenadores Remote-processing RPC-210