66 MSF Clock
66 : MSF Clock
- Author: Jamie Wood & Daniel Cannell
- Description: MSF radio clock
- GitHub repository
- Clock: 12500 Hz
How it works
The MSF radio clock bitstream is synchronised, decoded, and the time displayed on an LED display driven by a shift-register.
How to test
- Provide 12.5kHz clock to the clock pin, e.g. using the clock divider set to 0.
- Connect the data input to a WWVB / MSF receiver module.
- Connect the inverted input high if the module outputs a 1 when there is no carrier.
- Connect the shift_date input to a button. If held, the display will show date instead of time.
- Connect the shift register outputs to a 42-bit shift register chain. Bit 41 is shifted out first.
| Bit | Segment |
|---|---|
| 41-35 | Hours tens G-A (41=G, 35=A) |
| 34-28 | Hours ones G-A as above |
| 27-21 | Minutes tens G-A as above |
| 20-14 | Minutes ones G-A as above |
| 13-7 | Seconds tens G-A as above |
| 6-0 | Seconds ones G-A as above |
Time and date are always both shifted out, so an 84-bit shift register will show both simultaneously.
IO
| # | Input | Output |
|---|---|---|
| 0 | clock | shift_clk |
| 1 | reset | shift_data |
| 2 | data | shift_latch |
| 3 | inverted | |
| 4 | shift_date | |
| 5 | ||
| 6 | ||
| 7 |