FAR

Uploaded a Linux C source code of a tool to drive a HD44780 display connected to PC using FAR.

I've added the schematics and detailed function description. I'll also add the waveform details and timing adjustment instructions - unfortunately an oscilloscope is needed to exactly match the serial port TxD, byte and bit timers. I hope that the need for oscilloscope can be eliminated by adding some LEDs and using software to feed special calibration patterns to the serial port.

The tests were complicated by the fact that Chinese manufactured transitors are of very low quality. The ones already on the board had to be desoldered, new ones tested and placed. Due to a stupid mistake 4 PCB traces are missing, but that can be fixed quickly and proceed with tests. The software will be modified as the second prototype uses different bit ordering. The original was rather counter-intuitive.

Second prototype does not use the 7400. It is replaced with 2 transistors and the PCB is slightly redesigned.

The first prototype was successfully tested, it is able to drive an LCD display with a specialised software written in C.

The first prototype uses 556 dual timer and 4094 shift register. For signal inverting it uses 7400.