Where to GO from Here

SETUP AND OPERATION

If you want to do this:	Turn to
	Chapter
Save a program	3
Run a program at power up or
reset (autorun)	3
Know m ore abo ut serial por ts	4
Install a differ ent RAM mem ory chip	5
Using RAM to save variables	5
Run an assembly language program	5
Configure digital I/O lines	6
Detect on/off switch status	6
Use high c urre nt outputs	6
Connect an external opto rack	6
Calendar/ clock option	7
Connect Displays	8
Use a keypad	9
Measure voltages	10
Using inter rupts	12
Multi-mode counter	13
Use low power operation	14

Refer to the table of contents for a more detailed listing.

TROUBLESHOOTING

You would probably turn to this section because you could not get the sign on message. If you are getting a sign on message but can' t enter characters, then read section 5 below . T he following are tr oubleshooting hints when you can' t get anything.

1.Check the power source. If it is below 4.65 volts at the input pow er ter minal, the RPC -320 will r eset. Power is 5 ±0.25 volts. Make sure it is a clean 5 volt source . If it dips in term ittently to 4. 65 volts

(due to switching noise or ripple), the card will reset for about 100 ms. If the noise is frequent enough, the card will be in per manen t reset. Check U7, pin

8. If it is hig h (about 5 volts), then the car d is in reset. T his line should be low (about 0 volts).

2.Check the COM 0 port (J3). Rem ove the connector from COM 0. R efer to the outline dra wing ear lier in this chapter. Connect an oscilloscope (preferred) or a voltmete r to pin 3 (T xd) and gr ound. Pin 3 should be -6 volts or more negative. (Pin 1 is designated by the v symbol on the connecto r. Pin 3 is next to it, nearer the key opening.) If you have -6 volts or more, press the reset switch. If you have a scope

SECTION 2

attached, you should see a burst of activity. With a volt meter, you should see a change in voltage. Using a Fluke 8060A set to measure A C, you should see a mom entary rea ding above 2 volts.

3.Install the serial cable and make sure the voltages and output activity are still there. Output is from pin 3 on the VTC - 9F . If not, check to make sure something is not shorting th e output.

4.Check the serial pa ram eters on y our P C or termin al. They should be set to:

9600 baud, no parity, 8 data bits, 1 stop

5. If you are receiving a sign on me ssage but not ab le to enter characters, check U8, pin 4 for at least -6 volts. When it is near 0 volts, the terminal or PC's Tx line is not connected. When you pr ess a character on the terminal or P C, you should see the voltage go positive. Check the serial cable. Transmitted signals from the PC or terminal are from pin 5 on the 10 pin IDC connector .

If all of this fails, call technical support listed in chapter 1.

Page 2-4 RPC-320