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Open 7400 Competition / [Entry] 8-Channel, 6 -MSPS USB logic analyzer!
I have a bunch of Prolific PL2303 USB-to-Serial port adapter laying around, this is a very popular IC and from testing it can go all the way up to about 6 MSPS even though the datasheet dose not say that !
what the circuit here dose is take 8 parallel inputs and outputs a valid TTL RS232 signal that can be fed directly to the PL2303 RX pin, all the circuit needs a clock signal with the same baud rate as set in the software , i thought about including a micro controller to generate a clock signal that can be controlled from the computer software, but that would add more non 74 ICs to this circuit !
anyway ,
after thinking about it i decided to use the PL2303 to generate the Clock signal too, and that it by constantly sending out a series of 0 and 1s out of the TX pin , and that is done by the computer software
the circuit diagram is attached to this post