16F690 or whatever SEROUT to PC

[mackrackit]

All I can say is to give it a try. Maybe in your case it will not be to much of a problem if communications do not work every time. Just try sending the score again??

The MAX232 will not help you.

If you find it works part of the time, you may try 2400 baud. Sometimes a slower signal is more reliable and more tolerant.

I am not sure, the internal on your chip might be able to be calibrated. Some one else will have to help you if it can or needs to be.

[xnihilo]

thank you for your answers

[amgen]

My experience with newer PIC's w/8mhz int osc is they can be counted on for good enough freq for serial stuff....!!??

don
amgen

[Charles Linquis]

The 8Mhz internal oscillator in most 18F PICs will work fine with SEROUT/SEROUT2 at up to 9600 baud. If you use DEBUGOUT, you can extend that to at least 19.2Kbaud.

Amazingly enough, I have used the 8MHz internal oscillator on an 18F2221 to communicate with another PIC at 38.4Kbaud (using DEBUGOUT). This worked across 16 parts, and all were tested to be fully operational while running in a temperature chamber -20C to +85C.

And as far as whether to use a MAX232 or not - the level coming out of a PIC does not meet RS-232 specs. While it usually works, I would never sell a product that way.

[xnihilo]

The 8Mhz internal oscillator in most 18F PICs will work fine with SEROUT/SEROUT2 at up to 9600 baud. If you use DEBUGOUT, you can extend that to at least 19.2Kbaud.

Amazingly enough, I have used the 8MHz internal oscillator on an 18F2221 to communicate with another PIC at 38.4Kbaud (using DEBUGOUT). This worked across 16 parts, and all were tested to be fully operational while running in a temperature chamber -20C to +85C.

And as far as whether to use a MAX232 or not - the level coming out of a PIC does not meet RS-232 specs. While it usually works, I would never sell a product that way.

Fine, RS232 levels out of the pic is not right. Can I use a MAX232 chip to boost the signal then? Is there a post with the recommended connexion? I have the datasheet with a "typical application" circuit...

[Charles Linquis]

Just use the connections shown in the MAX datasheet. If you are using SEROUT/SEROUT2 make certain you use the "TRUE" settings (idle high), because the MAX chip inverts the signal. Tx of the PIC to T1in of the MAX. R1out of the MAX to Rx of the PIC.