I need to design and implement a very simple FPGA. There will be 34 TTL inputs. One (and only one) will be tripped every few seconds. I need the FPGA to report on which one was tripped. So the output will be six bits outputted via either RS232 or USB, whichever is easier to implement.
At this stage I need only one unit and I don't know anyone who'll make such a small quantity. Designing it on my own is not really an option because I'm a mechanical engineer :-)
Can anyone recommend someone who can do this for me?
Hi Yoni, I guess you're at Tel Aviv university from your email address. I have good news, it would appear that your university has an electrical engineering school. Why don't you wander down the corridor with some bagels and see if someone will help you out? ;-) HTH, Syms.
How long is the pulse? How long is the minimum time between 2 pulses? If the pulse has a length of some microseconds and if there is at least the time needed to send one byte to RS232 between two pulses, then you should use a microcontroller. If you need only one unit, you could try e.g. a header board for the LPC2148, like this one:
You can download the free GNU C compiler for it, or try some trial versions of commercial compilers for it. With a JTAG interface you can even debug the C programs on board, but for your task the program would be less than
10 lines, including RS232 communication, which is implemented in hardware on the microcontroller. Could be done in some minutes, when starting with some of the sample projects.
Of course, USB is much easier than RS232 :-) If you don't need USB, the LPC2148 is overkill for your project and you could use a PIC:
A small one, for less than 5 Euro would do it.
If you have very short pulses or small pauses between the pulses, so that new pulses can arrive while transfering, a FPGA or CPLD would be better. If you don't need to cache many pulses or additional information, a CPLD should work.
Frank Buss, email@example.com