Imported from GitHub: ansemjo/chronovfd · commit b1dde65 · license CERN-OHL-P-2.0

Description

hardware project for a clock around a russian ivl2-5/7 vfd and an esp32-wroom module

README

lcddriver

This isn't entirely my own design and is instead heavily based on David Johnson-Davies' "Low-Power LCD Clock" design on Technoblogy (archived: page, firmware). This was created shortly after the vfddriver v2 and was meant to use the same physical format and I2C protocol to be a drop-in replacement. In practice, I haven't really bothered to write a separate firmware and used it as a standalone clock with David's firmware instead.

It just needed a few small modifications from the original:

• Only PE0 is connected to the display's COM. PE1 is used for an LED and if you use the firmware as-is, you'll have a constantly flashing LED.

• I used an AVR32DB48 and apparently (?) it lacks some of the ADC stuff necessary to read its own voltage? So I just removed ADCSetup(), DisplayVoltage() and the references to it.

• Additionally, I removed the temperature display and reduced the blinking frequency of the colon by to 2 Hz.

There is also an inverted variant of the firmware, for when you want to operate the clock rotated by 180°, since the LCD segments are rotationally symmetric but the viewing angle is better from one side.

Compile

The firmware is in technoblogy-clock-firmware/.

The chip is supported by PlatformIO but back when I tried this, I couldn't get it to work. I got either Error: Unknown board ID 'AVR32DB48' or Error: This board doesn't support Arduino framework!. Therefore I used the method that David used and installed the DxCore in the Arduino IDE, which I then used to compile the firmware instead.

Flashing

For some reason the Arduino GUI couldn't directly flash my chip. Probably something about a wrong Python version. I manually installed pymcuprog in a Python 3.9.12 environment and used:

pymcuprog write -d avr32db48 -t uart -u /dev/ttyUSB1 -f lcdclock.ino.hex