@Rick_2047 I just needed to get IMPACT running on a lab PC today. Between their crap website, crap software install widget, crap license manager, ..., it took more than an hour.
At the beginning of the project I tried to convince the rest of the team to consider other vendors. Lattice would have been the best fit because we are actually using a Lattice FPGA.
Not that Lattice's software bugs haven't caused headaches
Traditional CPLD had a much simpler structure with very wide fan-in "product terms" (AND gates), and a few OR gates. The most recent CPLD families are more like just very small FPGAs (LUT-based architecture) with on-chip nonvolatile memory.
(Did I forget to mention, CPLDs store their program nonvolatilely on-chip, FPGAs need to be reprogrammed from external memory whenever they're turned on or reset)?
@Rick_2047 Anything you can do in a CPLD you ought to be able to code up in a day or less and see if it fits.
Project I'm working on we have 5 or 6 different boards around a main board with a big FPGA. Each of the little boards has a CPLD to implement some control registers, serial I/O, etc., under control of the main board. A lot of it is just used as I/O expander to let us control ADCs, etc., on the little boards.
The old-school CPLDs (with the wide fan-in gates) were good for asyncrounous logic because they had very easy to estimate propagation delays...the new ones I'm not so sure...
One thing I've wondered with CPLDs and FPGAs in general is why they don't make devices with a lower pin count, in-built regulators, config memory and all the rest of it with a fair few gates. I would have thought for example say for filtering / demodulation / protocol decoding of serial data that would be a pretty popular configuration or am I missing something?
During the firmware build process, the Map stage maps the top level signals of your firmware to physical FPGA pins. This assignment is almost always done manually by including pin assignments in a file called the constraints file (by the xilinx tool set, at least). If no constraints are found the...
basically, the clock ends up as a signal in your firmware on the FPGA
@Rick_2047, since it's a clock, you will also need to use a clock input buffer to tell the Xilinx tools that it's a clock so that it can be routed correctly in the FPGA clock paths
you should be able to use another clock buffer as an example for this one
the ucf file is only for physical pins, to specify which signals connect to which pins
usually you have a top-level hdl file which has all of the physical FPGA pins (except some special ones) as signals. These signals are then routed to various had modules as needed
so your top level wrapper contains all of your other modules
and your ucf file specifies which pins your top level wrapper signals go to
The IR LED question, the diagram shows the RGB LED string is powered off the Arduino itself - though the OP says externally powered. Question is, how exactly is it externally powered?
@jippie they could not call back to the hotline because they killed them self or because they have gotten over what was making them want to kill themselves. In the american "House of Cards" has a good scene related to this.
@Kortuk There are so many reasons why I should never be a therapist, or anything close to that. I also would never work as a High School (or lower) teacher, because I'd be cussing at the kids and insulting them. :)
I'm looking to build a computer the size that I can use small jumper cables for the programming, no soldering. Of course it won't be able to do much more than binary counting, etc.
What kind of parts would I use? I would like to assemble inverters and diodes to build the AND gates, XOR gates, et...
@angelatlarge "Wannabe" doesn't factor into it. I just don't have what it takes to answer those questions. I will gladly bow to others who want to give it a try!
@angelatlarge A coworker is building his own 3-D printer. His is different than what's out there already in that he's writing his software from scratch-- including the G-Code interpreter and all of the complex stepper motor motion stuff. He's using an Arm Cortex-M4 instead of the typical Arduino stuff.
Serious question to you guys: how do you motivate yourself to work on a electronics related hobby project when you spend 8+ hours doing it for a living?
I come home from usually about 10-11 hours of work and just want to eat, and watch TV, and play football =/
@DavidKessner Good to know. I may have to post some questions about it later. I'll be sure to include a piece of wire connected to a crystal for your pleasure.
@NickHalden I just finished my degree, taking my time with job hunting. And I did get into playing around with electronics in order to brew better beer :)
@ThePhoton When I need more advanced stuff, I just borrow it from work. O-Scopes, etc. If I a need to solder something complex, I'll bring it in to work.
Hmm, I just feel like I'm never going to get "ahead" if I'm not also working on this stuff at home. I learn a decent amount at work, but the scope of our products is pretty limited...
