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Controlling 4-Digid 7 segment display with custom program via USB.

futyseq

New Member
Hello,
I have homework and I am supposed to do exactly what is in the thread name. I successfully made 1 digit display controlled with FT232 but I don't know how to do 4 digits and definitely don't know how to make the program. Can anyone help me? I want to know stuff like which IC should I use, how to wire them etc.

Thanks a bunch!

edit: Sorry, I forgot to mention that we can't use microcontrollers. Only stuff like serial converters, RAMs, counters, 7 segment display convertors etc.
 
Last edited:

Nigel Goodwin

Super Moderator
Most Helpful Member
Use an FT232 to feed a microcontroller, and send serial data to the microcontroller - which then feeds the displays. You could do it all easily with an Arduino, and there are plenty of examples out there.
 

futyseq

New Member
Use an FT232 to feed a microcontroller, and send serial data to the microcontroller - which then feeds the displays. You could do it all easily with an Arduino, and there are plenty of examples out there.
Sorry, I forgot to mention that we can't use microcontrollers. Only stuff like serial converters, RAMs, counters, 7 segment display convertors etc.
 

Ian Rogers

User Extraordinaire
Forum Supporter
Most Helpful Member
If you connect the FT232 to a PC, you can bit bang SPI to a 74hc595 then cascade to 4 digits... pretty easy.. You're only issue is pins available on these FT232 boards... You would need one with at least three outputs SCK data and CS .. Most have two outs and two ins... You need one with TD, RTS and DTR...

I don't know if ant RS232 -> SPI chips are available.. I used to do it through the old 9pin serial port..
 

Nigel Goodwin

Super Moderator
Most Helpful Member
If you connect the FT232 to a PC, you can bit bang SPI to a 74hc595 then cascade to 4 digits... pretty easy.. You're only issue is pins available on these FT232 boards... You would need one with at least three outputs SCK data and CS .. Most have two outs and two ins... You need one with TD, RTS and DTR...

I don't know if ant RS232 -> SPI chips are available.. I used to do it through the old 9pin serial port..
Old parallel port probably even easier :D
 

Nigel Goodwin

Super Moderator
Most Helpful Member
I had a book... "Interfacing the PC" Its mainly why I used pascal..

PC Interfacing (bookshop.org)

I found it excellent in connecting external devices to a pc..
I have the same book - have you seen the price on the link you posted?.

I also have "Build Your Own Low-Cost Data Acquisition and Display Devices by Jeffery Hirst Johnson".
 

Les Jones

Well-Known Member
Most Helpful Member
FTDI make a USB to parallel converter. It is a FT245RL. I bought one several years ago but have not yet tried using it.
If you allowed to use a UART it would make your design simpler. You could then shift the parallel data into 4 or more (Depending if you sent the data in binary or ASCII encoded form.) The output of 4 stages of the shift registers could then be fed into 4 x 7 segment decoder/drivers. What you have done so far probably performs a UART function.

Les.
 

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