https://github.com/stecman/avr-doomclock
GPS clock on an ATTiny with MAX7219 7-segment driver
https://github.com/stecman/avr-doomclock
attiny13a avr avr-gcc digital-clock firmware microcontroller
Last synced: about 1 month ago
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GPS clock on an ATTiny with MAX7219 7-segment driver
- Host: GitHub
- URL: https://github.com/stecman/avr-doomclock
- Owner: stecman
- License: mit
- Created: 2019-02-04T18:33:58.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2021-07-26T10:12:44.000Z (over 3 years ago)
- Last Synced: 2025-01-17T19:43:22.646Z (3 months ago)
- Topics: attiny13a, avr, avr-gcc, digital-clock, firmware, microcontroller
- Language: C
- Homepage: https://hackaday.io/project/163826-gps-wall-clock
- Size: 78.1 KB
- Stars: 4
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Tiny GPS Clock
This is a `hh:mm:ss` clock that runs from the time contained in NMEA RMC sentences.
The code is targeted at an Atmel ATTiny13A.
Notes:
- As the target microcontroller doesn't have enough RAM to store a full NMEA sentence,
this project uses a custom parser that only reads RMC ("Recommended Minimum") sentences from a UART
and extracts the time from that (see`nmea.c`).
- The ATTiny13A lacks SPI and UART peripherals, so these are implemented in software.
Schematic and construction details can be found on [this project's hackaday.io page](https://hackaday.io/project/163826-gps-wall-clock).
## Building and flashing
The `avr-gcc` toolchain is required to build, but there are no other external dependencies.
```sh
# Build
make
# Flash with programmer configured in Makefile
make flash
```
## Testing
The simple test suite for NMEA RMC sentence decoding can be run manually with:
```sh
make test
```