I needed a quick way to test hobby servos that didn't involve radios, etc.  I had a PIC18F development board with an RS-232 port lying around, so I wrote a quick and dirty tester.
I'm providing the source (in PBP 3) and the .HEX file.  It does require an 18F PIC with a hardware serial port and 16K or more of FLASH simply because it presents so much text to help the user. The serial port runs at 9600 N-8-1.
It produces 8 channels of PWM for the servos with a refresh rate of 50Hz (20 mSec).  You can increase or decrease the pulse width with the "U" or "D" keys on the keyboard.  D-T interrupts are used, and the ints are shut off when the registers are updated since the values are 16-bit.
All should be clear by looking at the source.
You can find the files at ServoControllerCL3.zip
www.charleslinquist.com/ServoControllerCL3.zip
	
	
		
		
	
	
		

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Re: serial LCD 1602 Backpack using PIC16F690 for Hitach HD44780
one last update:
jackberg1 - 1st November 2025, 17:11added an PGM Sw on RA3
to edit the baud rate:
turn off the LCD display, press & hold the PGM sw, turn on the LCD
line 1 will show "Press to Select" , line 2 : "Baud Rate:"...