Hi,
I was looking for a display for my DAC project and found 256x48 VFD displays sold in bulk. They looked good so I bought some and made a PCB with everything needed to power and control it.
Module size is 170x46 mm (display itself is 150x40)
To control it I put a STM32 MCU and since the MCU is already there, it makes it logical to make it useful for process all other front panel knobs: encoders, buttons, leds, potentiometers etc. Of course for a specific build it is better to just put everything on one board but at the moment exact set of controls needed is unknown so I've tried to make it somewhat universal by putting two FFC connector on both sides for expansion modules:
On each of these expansion boards there are 2xI2C buses, one MCU ADC input and 6 gpios (unique for both sides).
Main 12pin header has supply input (5V), and MCU GPIOs. Pins are chosen so that I2C, SPI and UART peripherals are available here. So again, pretty universal.
Schematic is nothing special, it is attached.
I do not have the side expansion modules yet but for my purposes I'm going to have encoder with some LEDs+buttons.
Regarding the firmware: the display is supported by u8g2 library which makes it really easy to do some sketches with lopaka app:
I'm sharing this because I have more such modules assembled that I really need and consider selling these in future, the firmware for MCU is also going to be published.
But I have two questions:
1. Maybe it makes sense to create some 'default' firmware for those who don't want to deal with MCU coding? For example, firmware which receives I2S WCK and prints current sampling rate etc.
2. What kind of expansion modules are needed? Of course it is not possible to make it 100% universal.
I was looking for a display for my DAC project and found 256x48 VFD displays sold in bulk. They looked good so I bought some and made a PCB with everything needed to power and control it.
Module size is 170x46 mm (display itself is 150x40)
To control it I put a STM32 MCU and since the MCU is already there, it makes it logical to make it useful for process all other front panel knobs: encoders, buttons, leds, potentiometers etc. Of course for a specific build it is better to just put everything on one board but at the moment exact set of controls needed is unknown so I've tried to make it somewhat universal by putting two FFC connector on both sides for expansion modules:
On each of these expansion boards there are 2xI2C buses, one MCU ADC input and 6 gpios (unique for both sides).
Main 12pin header has supply input (5V), and MCU GPIOs. Pins are chosen so that I2C, SPI and UART peripherals are available here. So again, pretty universal.
Schematic is nothing special, it is attached.
I do not have the side expansion modules yet but for my purposes I'm going to have encoder with some LEDs+buttons.
Regarding the firmware: the display is supported by u8g2 library which makes it really easy to do some sketches with lopaka app:
I'm sharing this because I have more such modules assembled that I really need and consider selling these in future, the firmware for MCU is also going to be published.
But I have two questions:
1. Maybe it makes sense to create some 'default' firmware for those who don't want to deal with MCU coding? For example, firmware which receives I2S WCK and prints current sampling rate etc.
2. What kind of expansion modules are needed? Of course it is not possible to make it 100% universal.
