60 Second Timer

The sixty second timer, which counted from 0-59 and reset back to 0 after 59, can be implemented using a 0 - 9 up synchronous counter along with a 0 - 5 up asynchronous counter. The 0 - 9 counter used a 4-bit synchronous binary counter, or CNTR_4BIN_S in Multisim, connected to a BCD to 7-segment decoder. It had a 4-input NAND gate that triggered on 9 that connected to the 0 - 5 counter as its clock. This counter used three positive edge triggered J/K flip flops, also connected to a BCD to 7-segment decoder. Both of these decoders were wired to a series of multiplexers that were then connected to outputs for the 7-segment display. The inbuilt clock in the S6 had a frequency of 8 mHz, way too fast for a sixty second display. To solve this, the clock input was connected to multiple 7-stage binary counters that were fed into the 0 - 9 counter.