Alan Sailer
Member
Hello,
I am tapping into group wisdom to solve a problem. I am using an old 18A chip to make a timer. The output pins are all being used to send two BCD digits to the display.
I need to somehow supply a signal when the count reaches zero to set off my MP3 player/speaker.
One non-elegent idea was to send a BCD number to the display that will present all one's to the display. The display is a HEX display so it will display FF, which is easy to see is nonsense. However I can use a quad input NAND gate to decode that unique input into a signal that will trigger the speaker. It's kind of brute force, adds another chip and I will also have that brief display of the hack (FF = Fail/Fail?).
Is there another idea I am missing? The only other output I can see is the serout but this is part of the programming circuit. I also see that the 18M2 has more output pins.
So one of those might be the best bet.
Cheers.
I am tapping into group wisdom to solve a problem. I am using an old 18A chip to make a timer. The output pins are all being used to send two BCD digits to the display.
I need to somehow supply a signal when the count reaches zero to set off my MP3 player/speaker.
One non-elegent idea was to send a BCD number to the display that will present all one's to the display. The display is a HEX display so it will display FF, which is easy to see is nonsense. However I can use a quad input NAND gate to decode that unique input into a signal that will trigger the speaker. It's kind of brute force, adds another chip and I will also have that brief display of the hack (FF = Fail/Fail?).
Is there another idea I am missing? The only other output I can see is the serout but this is part of the programming circuit. I also see that the 18M2 has more output pins.
So one of those might be the best bet.
Cheers.