I am building a timer that goes from 9 - 0 and then stops. I am using a 555 chip for my timer running at 1 pps. my countdown chip is a SN74LS193. My bcd to seven segment decoder driver is a SN74LS247. It is driving a seven segment display that is common cathode. I am having difficulty making my 193 chip countdown. Could you please show me the pin outs and where they go for the 193 and the 247 to allow my display to countdown from 9 - 0 and stop. I also need to be able to reset my 0 back to 9 for another countdown operation. Your help will be greatly appreciated. This is a project for the youth of our church that I am putting together. God bless, George Keesee