33 Lambda Clock
33 : Lambda Clock
- Author: Emre Caliskan
- Description: A 10-digit digital clock/calendar with alarm logic, multiplexed over 3 cascading 74HC595 shift registers.
- GitHub repository
- Open in 3D viewer
- Clock: 32768 Hz
How it works
The Lambda Clock is a highly-optimized full digital calendar and clock built for a 10-digit 7-segment multiplexed display architecture using three cascaded 74HC595 shift registers. It features a fully synchronous clock-enable domain (tick-based) that guarantees ASIC synthesis stability. It parses the base 1Hz and 1kHz ticks to manipulate independent BCD limits natively preventing binary-to-BCD resource explosion. It enforces leap-year restrictions automatically and incorporates an 8-state settings menu, tracking and individually updating Days, Months, Years, and Time. A built-in Alarm module is continuously checked against current active BCD time registers.
How to test
The clock provides an 8-stage interactive module.
- BTN_MODE (ui[0]): Cycles between Normal Time, Minutes Edit, Hours Edit, Days Edit, Months Edit, Years Edit, Alarm Min Edit, Alarm Hour Edit.
- BTN_INC (ui[1]): Increments the currently selected active time/date block.
- BTN_DEC (ui[2]): Decrements the currently selected active block.
- BTN_RST (ui[3]): Manually resets the clock back to the default time (14:10 01.01.2002).
External hardware
- Three (3) 74HC595 Shift Registers (Cascaded).
- Two (2) 5641AS 4-Digit 7-Segment Displays.
- One (1) 5621AS 2-Digit 7-Segment Display.
- Active Buzzer (for output uo[3]).
- Optional LEDs (for uo[4], uo[5], uo[6]) for Debug/Status indicators.
IO
| # | Input | Output | Bidirectional |
|---|---|---|---|
| 0 | BTN_MODE | SCLK | |
| 1 | BTN_INC | RCLK | |
| 2 | BTN_DEC | DIO | |
| 3 | BTN_RST | BUZZER | |
| 4 | LED_SETUP | ||
| 5 | LED_ALARM | ||
| 6 | LED_ALARM_MATCH | ||
| 7 |