Easy to Use Programmable Logic Probe

Description

This is a simple version of a classical logic probe. There are no settings or switches. You supply the power and the probe is ready to show you the logical state of the signal at its tip.
The logic probe is capable of displaying logic high (Vin > 2/3 * Vcc, displayed green), logic low (Vin < 1/3 * Vcc, displayed red) and Hi-Z (1/3 * Vcc < Vin < 2/3 * Vcc, displayed yellow) states. A separate white LED indicates an edge transition. The combination of a yellow color and a while LED shows high-frequency signal.
The logic probe is built around Atmel ATtiny45 and it includes the bootloader that works though the probe tip. There is no need to disassemble the probe to update this firmware and all you need is a USB to UART adapter. The Python scripts for generating the update files are included.
For the first second after power up the probe displays white color on both LEDs. This serves two purposes. The first one is self test that verifies that all LEDs are functional. Additionally, the bootloader is listening for a command during this time. If a '?' is received (UART 38400 8N1), then bootloader will continue to listen for further commands.
The logic probe can run from 3.3 V or 5 V supply, and it includes reverse voltage protection.
Source code and design files are available at https://github.com/ataradov/logic