What is max cable length between the PIC and the serial LCD, will it work whit a 15 - 20 meter long cable?
Any special cable needed?
Serial LCD http://www.parallax.com/dl/docs/prod...alLCD-RevE.pdf
What is max cable length between the PIC and the serial LCD, will it work whit a 15 - 20 meter long cable?
Any special cable needed?
Serial LCD http://www.parallax.com/dl/docs/prod...alLCD-RevE.pdf
Assuming you are using a max232 device in your hardware it is well within the limits.
Edit: and this link has some different results: http://www.hamradio.cc/computer/RS23...unications.php
RS232 cable length according to Texas Instruments Baud rate Maximum cable length (ft) 19200 50 9600 500 4800 1000 2400 3000
Last edited by ScaleRobotics; - 29th June 2010 at 16:44.
I want to connect a display to this devboard http://www.mikroe.com/eng/products/v...6b-plc-system/ and it has the MAX232 onboard.
Do I have to use a MAX232 in both ends (display and devboard) or just that one on the devboard.
If you take a look at this display http://www.sparkfun.com/datasheets/LCD/SerLCD_V2_5.PDF it take incoming "TTL level" signals, should I still use a MAX232 whit this display, the MAX232 converts the PICīs TTL signals to RS232 signals that has a voltage upp to -+10 volts so if I have a MAX232 at the sender side I will damage the 16F88 on the display hardware if I donīt convert the RS232 signals back to TTL level signals?
I am not sure how far TTL would travel. I would guess that it is much shorter than using a max232, since you don't have the range of voltage available. You could test it without...., or you could put a max232 on both sides, or...
You might be able to get by using a max232 on your hardware side, and on the serial lcd side, use a resistor as shown in the PBP manual under SERIN example. This 22k resistor would protect your serial lcd (RX) from the max232 voltages, but should preserve the distance, since the +/- voltage is getting all the way to the resistor.
Last edited by ScaleRobotics; - 29th June 2010 at 19:56.
Then again, Darrel got 25 feet using a normal LCD. See this thread: http://www.picbasic.co.uk/forum/show...7417#post47417
So maybe at the 2400 baud rate, you could get enough distance using ttl?
Thank you for your help.
I have now ordered this display http://www.sparkfun.com/commerce/pro...oducts_id=9568 and will come back whit some feedback when I have make some tests.
I just tried whit 9600 baud on a 11 meters shielded cable and it seems work well so far
I have no MAX232 on the sender side, I just connect the RX direct to PORTC.6
Update:
9600 Baud and a 15 meter long cat5 cable and it still working whit this code and TTL level signals direct from the PIC.
counter is a long sized variable.Code:start: SEROUT2 lcdtx,84,[254,1] SEROUT2 lcdtx,84,[254,line1,dec counter," ROW1"] SEROUT2 lcdtx,84,[254,line2,dec counter," ROW2"] SEROUT2 lcdtx,84,[254,line3,dec counter," ROW3"] SEROUT2 lcdtx,84,[254,line4,dec counter," ROW4"] pause 500 goto start
Last edited by ScaleRobotics; - 2nd July 2010 at 20:46.
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