Keypad miniBoard

[Bilal]

hi I am new in CCS forum and with PIC controllers and am making a PIC16F877A Board.
I have connect 2x16 LCD, Temp scn, External EEPROM, 3310 Graphic LCD, 3 Buttons, and 5 LEDs.
Now I want to connect 4x4 Keypad with it, but available Pins are not enough.
So I have decided to connect a separate PIC16F876A and connect keypad with it. This secondary controller will send an ASCII code to PIC16F877A so only one PIN of my primary controller will be utilized. But I don't know how it will receives ASCII and how 16F876A will transmit.
I will be thankful if any one will help me with this.
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[Bilal]

im using CCS_PCWHD_v.4.093
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[PCM programmer]

Use the hardware UART on the 16F876A to send the ASCII bytes to
the hardware UART on the 16F877A. See the #use rs232() statement
in the CCS compiler manual, and look at examples in this forum.

[Bilal]

will it be the same how my EEPROM works or it is different protocol???
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[Bilal]

My RC6/Tx and RC7/Rx of PIC16f877A are already be used with other devices.
Maybe it will not work.
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[Bilal]

Is there any other solution??
I will be very thankful
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[SherpaDoug]

If your PIC16f877A is only handling a keyboard maybe you can use a software UART on it? That can be done on any pins you choose.
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The search for better is endless. Instead simply find very good and get the job done.

[John P]

One way to save pins is to use 74HC595 serial to parallel converter chips for outgoing data, and 74HC165 parallel to serial chips for inputs. You can connect them to the SPI port and have as many interface lines as you want, with only 4 processor pins needed.