Re: Analog?
Yes they do require a few external components hence why I asked if you intedend to design a board for the robot project. You can probably source a suitable development board which will address your needs as well.
Re: Analog?
Adam - I think I'm going to be running into my hardware limitations quite frequently with the FPGA projects. That's why my fallback is to go the familiar route and throw a little MCU at the problem. Doesn't the converter you mention still require an op-am or a comparator or something similar?
To start with, I'm just using the Spartan6 LX9 board, but eventually, I'll need access to more of the pins so I'll have to go to a different board either of my or someone else's design.
Karl
5/30/2012 2:07:48 PM
User Rank Guru
Re: Analog?
Depending on the width of each input and the simultaneously it could range from an I/O pin for each to a mpx interface that would not be simultaneous.
So not to distract you, Thankyou and enjoy.
Re: Analog?
@Duane, are you designing a new board or using the development board you have for the robot? Depending upon the frequency of the ADC / DAC you could undertake a delta sigma convertor.
Re: Analog?
I'm thinking in terms of having a dozen or maybe even more sensors around the robot for obstacle avoidance. A lot of people just use four but given that I want this thing to survive a potentially crowded trade show environment, four won't cut it.
Without analog on the FPGA, I'll just put a tiny little MCU on the sensor - maybe a six-pin PIC10F part or one of the new tiny chip scale LPC1100 parts - and do the D/A there. I'll bring all of that data in to the FPGA simultaneously. I'm not sure what the best way to get the data in will be. I could probably create I2C peripherals in the FPGA for each input, but I'd rather find a simpler solution.
Karl
5/30/2012 1:31:01 PM
User Rank Guru
Re: Analog?
On the DSP side of things on the FPGA things like FIR filters, FFTs and others are being implemented wiithout MCUs. Seems like the analog is not typically on the FPGA now.
If these functions are interesting, there are some very opinionated folks who are totally sold on FPGAs.
Wish I knew more first hand, but have seen a lot of comments that DSP is handled very well in FPGAs.
It looks like they are able to process the raw data on the way in and send the result to the CPU. That sounds like what you want.
A system builder tool (DSP Builder) should have plug-ins to help.
Re: Analog?
@Duane: There have been a numbrer of Field-Programmable Analog Array (FPAA) type devices in the past that have "crashed and burned"
Today, Cypress have what they call Programmable SoCs (PSoCs) that contain a hard core processor (8051 or ARM), some reasonably sophisticated programmable analog, and some (as I recall) not-so-sophisticated programmable digital.
Actel (acquired by Microsemi) have their SmartFusion mixed-signal FPGAs, which contain a hard ARM Cortex-M3 processor, some programmable analog, and some regular programmable FPGA fabric.
Until recently, the high-end FPGAs didn't include any analog. But my understanding is that all of the new Xilinx 7 series FPGA families -- including the Zynq 7000 EPP (which also contains a hard dual core ARM Cortex-A9) -- boasts something called Agile Mixed Signal (AMS). I don't have the full specs to hand .... maybe I will cover this in a future Ask Max column...
Analog?
I've been seeing bits and pieces referring to analog in some of the newer FPGAs. Am I correct in the assumption that analog capability is a fairly new thing in the FPGA world and only just starting to appear in the higher end devices?
One of the FPGA appeals for the robot I'm building is the ability to take a lot of sensor input in at the same time. Having a bunch of A/D inputs would help that goal greatly. I can still get there by doing the A/D with a tiny micro for each analog sensor, but it would be really cool to not have to have all or those extra MCUs.
Karl
5/27/2012 11:46:55 AM
User Rank Guru
Re: What are the microprocessors processing?
So the accumulator is a register and the multiplier is constructed from memory.
It can be a class containing those two classes and at least modelled as such. Synthesis is another thing.
I believe all those things are defined as HDL modules and logically represented as reg, memory, combinational. So synthesis identifies that the hard block should be used and the other tools use the HDL. Even the memory blocks are done with HDL and synthesis chooses the hard memory block, place and route picks one and hooks it up.
I will tune in tomorrow.
Re: What are the microprocessors processing?
@Karl: Today's medium to high-end FPGAs include DSP blocks (soletimes called slices). These hard core DSP blocks contain a multiplier and an accumulator (plus loys of other sophisticated stuff). A high-end FPGA can literally have thousands of these DSP blocks. Also there will be megabits of memory presented as hard core blocks.
Re the term "FPGA" -- see my blog "Mind the FPGA Gap," which I will be posting first thing tomorrow morning (Monday 28 May)
|
 |
We consider complementary versus analogous colors and the meaning of terms like shade, tint, and hue. We also introduce the concept of psychological primary colors.
This "retrospective" blog describes how I became involved in testing microprocessors in 1976, and how microprocessors have influenced my professional work for many years...
The appellation "primary colors" refers to a small collection of colors that can be combined to form a range of additional colors, but which "small collection of colors" should we use as our primaries?
Today's FPGAs already integrate a substantial amount of "stuff" (MCU cores, programmable fabric, on-chip memory, etc.), so what's left to integrate and why is this being left for the future?
To celebrate Geek Pride Day, Sylvie Barak has created a mega-cool infographic that depicts how geeks have been building the Internet since 1832.
|
Tweet This
