Hi. I'm trying to make a count down timer for my soccer club. I've got the count down happening with 2 x 7-segment led display, 4510s and 4511s (including a 32Khz crystal). I'm having difficulty working out how to get the count from 00 to 59. I've put in a preset switch that sets to 59, then it counts down from there. However to automate it when it sees 99 I don't know how to tackle. Please can someone help.