anybody know how to connect a pic16f877 to a max232?

[Adamant]

pic16f873 max232

max data sheet
javascriptpenreq('http://www.ortodoxism.ro/datasheets/maxim/MAX220-MAX249.pdf')

pic16f877 data sheet
**broken link removed**

and this garbage LCD from Matrix Orbital

**broken link removed**


Matrix Orbital and their infinite wisdom don't even know how to connect it.



I just need the simplest connection possible, TTL, or RS232

 

[Cortex]

max232 wiring

you must use the Uart Pins
RC7 and RC6 connect to TX and RX of the Max232

 

[Adamant]

how to connect max232

you must use the Uart Pins
RC7 and RC6 connect to TX and RX of the Max232

thanks Cortex but i've done that already and it still doesn't work. The want TTL or 232 connection to the LCD.

 

[VVV]

pic16f877 max232

I would first test the two separately.

First try using the hyperterminal with your LCD. Make sure the LCD can talk over RS-232. Just send ASCII characters to match the commands, etc. If meaningful things happen on the LCD, you will know it's working. At this point you can correct wiring problems, if any.

Next, using RC6, RC7 and a MAX232, connect to the PC, runnig hyperterminal. That way you check your PIC code. I would write a very simple code that echoes the character back to the PC. This will keep the code to a minimum, but it will help you detect wiring problems, as well as code problems, such as baud rate, enabling the USART, or fogetting to make the TX pin an output, etc.

Once you get that working, conect the LCD to your PIC board.
Now that you know that each module is functional, if the assembly still does not work you can look at your wiring, code, etc.

By the way, I don't think you need the MAX232 between the PIC and the LCD. All you need is a couple of gates, 7404. It seems to me this LCD does not use "true" RS-232 signals, just TTL level, which generally work with a PC.
However, only try using the gates once you have managed to make the two work together using the MAX232.

 

[IanP]

how connect max232 and pic16f877

To connect this LCD to a PIC (or any other microcontroller) you don't need MAX232 driver. This LCD has very simple resistor-transistor inverter at the Rx input and will accept standard RS-232 level as well as any 0-5V logic.
The only one thing you will need is an iverter gate so signal from PICs UART TX is negated ..

rgs ..