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SOI Sentinel
Joined: 30 Mar 2006
Posts: 44
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 Posted: Wed Mar 14, 2007 3:39 pm Post subject: Mid/Upper Level Controller |
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I seem to remember ginge wanting to have the option to star network his I2C busses for maximum bandwidth via an FPGA (was that in the Openservo V3 thread?).
I know some people run their controls over their PC. Others want stand-alone. If you can take the boardspace requirements, it looks like TI might have a good ARM MCU for you.
http://focus.ti.com/docs/prod/folders/print/tms470r1b1m.html
I've been considering this board for other reasons (Arm7TDMI+ external bus interface made it tempting for several high memory projects), but it has five hardware I2C interfaces, making it a candidate for a single chip Openservo master hub.
Short of an Ethernet interface, I can't think of much else I'd have liked to see crammed into this thing, it just have everything.
I'm also curious what other people are using (besides a PC) as their higher level controllers for their projects. |
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ginge
Site Admin
Joined: 14 Jan 2006
Posts: 1029
Location: Manchester, UK
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| Posted: Wed Mar 14, 2007 4:36 pm Post subject: |
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SOI, That looks nice.
I just got some samples for the ATMEL ARM chip range. I am planning on seeing how they pan out as they are pretty cheap. The multiple I2C loos attractive, and I might even reconsider my options.
I currently use two gumstix interfaces to communicate with my servos. It works nicely, and runs Linux. I also have a couple of PIC processors to do some of the downstream staring of I2C busses.
Barry
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pbreed
Joined: 13 Mar 2007
Posts: 5
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| Posted: Wed Mar 14, 2007 5:22 pm Post subject: |
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SOI Sentinel
Joined: 30 Mar 2006
Posts: 44
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| Posted: Wed Mar 14, 2007 9:40 pm Post subject: |
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I haven't had an application for a Netburner yet. However, I do know the reputation. I HIGHLY respect anyone that I don't have to sign over my firstborn to get the hands on the hardware or software. Your product would make a great gateway for a web controlled robot design, for instance. Probably be a good start for that 6 servo ethernet bridge grouping we were discussing in the Openservo V3 thread recently. Plenty of horses and space, even in the low end 5270.
I'll probably have to take another look at them and see if it would be appropriate to hook up my 8 bit digital camera to their bus and see if I can get a framegrabber running. |
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mpthompson
Joined: 02 Jan 2006
Posts: 650
Location: San Carlos, CA
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| Posted: Fri Mar 16, 2007 8:13 am Post subject: |
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| Quote: | I seem to remember ginge wanting to have the option to star network his I2C busses for maximum bandwidth via an FPGA (was that in the Openservo V3 thread?).
...
I'm also curious what other people are using (besides a PC) as their higher level controllers for their projects. |
I'm still contemplating what controller to use for the biped I'll be building out with OpenServos, but right now the leading candidate for me is the Blackfin Handy Board. It is being co-developed by Analog Devices and a professor at the University of Massachusetts specifically for robotics experimentation. It's not quite available yet, but the basic specs look promising. It has a 600MHz Blackfin DSP/MCU paired with a Spartan3E FPGA for soft core peripherals. My plan would be to implement custom communication between the FPGA and the OpenServos (or an OpenServo derived design that replaces I2C with something a little more noise tolerant).
The nice thing about the FPGA combined with an OpenServo is the communication overhead between the controller and the OpenServo can be reduced to virtually zero. The MCU just write/reads position/velocity/curve data to registers on the FPGA and the FPGA hardware shifts the data to and from the OpenServos transparently. No interrupt handlers, software drivers or anything. Depending on FPGA resources available, the OpenServos can be configured in a star configuration for maximum throughput or short bus segments for better resource utilization.
-Mike |
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SOI Sentinel
Joined: 30 Mar 2006
Posts: 44
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| Posted: Fri Mar 16, 2007 2:30 pm Post subject: |
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| I've been looking at the Blackfin Stamp boards for a while as I've wanted to work with a vision system. However, that looks even better. Any idea what the cost will be? |
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linuxguy
Joined: 16 Oct 2006
Posts: 120
Location: Beaverton, OR
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| Posted: Fri Mar 16, 2007 4:12 pm Post subject: Re: Mid/Upper Level Controller |
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Very nice specs! If only it were easier to use those QFN, etc type packages. I'm just not up to soldering those by hand.
| "SOI Sentinel" wrote: | | I'm also curious what other people are using (besides a PC) as their higher level controllers for their projects. |
Right now I am just using Basic Micro's Basic ATOM PRO (graduated from the Basic ATOM) microcontroller on the Lynxmotion Mini Atom Bot Board. However, I very much want to get into other types of microcontrollers and am working on a design for a small dual PIC controller (18F2680 or 18F2550 and a dsPIC 4012, which will be optional). I just ordered the MCUs for this project and it will be based on a board designed by another Lynxmotion user (sapian59). I won't have a problem designing the circuitry for this, but I have never designed a PCB.
I also want to work with AVR (Atmega128, and of course Open Servos) and ARM based MCUs (New Micros Pluga2138 and Tini2138). I am curious as to whether the SOIC type packages are really any harder to use than standard DIP packages.
8-Dale
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linuxguy
Joined: 16 Oct 2006
Posts: 120
Location: Beaverton, OR
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| Posted: Fri Mar 16, 2007 4:17 pm Post subject: |
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| "mpthompson" wrote: | | I'm still contemplating what controller to use for the biped I'll be building out with OpenServos, but right now the leading candidate for me is the Blackfin Handy Board. |
I've also been looking at the BlackFin MCUs, and have been a fan of Analog Devices stuff for a long time. If they get Linux on this Handy Board, I'll have to look at it real seriously.
8-Dale
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linuxguy
Joined: 16 Oct 2006
Posts: 120
Location: Beaverton, OR
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| Posted: Fri Mar 16, 2007 4:21 pm Post subject: |
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| "SOI Sentinel" wrote: | | I've been looking at the Blackfin Stamp boards for a while as I've wanted to work with a vision system. However, that looks even better. |
I've just started tinkering with RoboRealm (unfortunately only available for Windows). I'm also working on socket communications from Python, since RoboRealm has a socket server built into it. I've done some very simple socket communication between two Python scripts running under Linux and/or Windows.
8-Dale
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No, Mr. Jobs, the BiPod is a ROBOT. It does not play music OR interface with iTunes.
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mpthompson
Joined: 02 Jan 2006
Posts: 650
Location: San Carlos, CA
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| Posted: Fri Mar 16, 2007 5:08 pm Post subject: |
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| Quote: | | I've been looking at the Blackfin Stamp boards for a while as I've wanted to work with a vision system. However, that looks even better. Any idea what the cost will be? |
Unfortunately, I don't. I too am interested in the board not only for the FPGA, but the vision capabilities as well. I expect the price to be somewhere between $600 and $1000, but will be pleasantly surprised if it is less. If it has the capability I think it will, it would be a bargain compared to putting together all the components yourself on a board.
I'm a bit worried about the BlackFin Handy Board coming available because they claim it will be out in Q1 2007 which is almost over and the mail list has been dead silent. I'm sure I just need to decide to use something else and it will then be released after I invest money in a different platform  .
-Mike |
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SOI Sentinel
Joined: 30 Mar 2006
Posts: 44
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| Posted: Sat Mar 17, 2007 3:47 am Post subject: |
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linuxguy:
While this is surface mount, it's not impossible to do by hand. This is a TQFP package, so it has closely spaced leads. Shouldn't be any worse than the ATMega168, just larger.
mpthompson:
If you can live without the FPGA, you might be able to get by with the
Stamp board I mentioned.
Digikey part #: ADDS-BF537-STAMP
$226
Specs from Analog's website:
Features
* Linux OS based on uClinux 2.6.x, GPL license-compliant, complete kernel and driver source code
* GNU gcc (C/C++) support with gdb/kgdb debug capabilities over Ethernet and JTAG
* Das U-Boot bootloader
* Complete Linux IP stack including standard protocols
* Device drivers for on board peripherals
Technical Specs
* ADSP-BF537 500 MHz Blackfin? Processor
- IEEE 802.3-Compliant 10/100 Ethernet MAC
- Controller Area Network (CAN) 2.0B Interface
* 64 Mbytes SDRAM
* 4 Mbytes Flash Memory
* RS232 serial interface
* I/O connectors for Blackfin peripherals (SPI, two-wire interface, IrDA?, SPORT0 and SPORT1, Timers, PPI (general purpose parallel high speed interface, glueless TFT flat panel))
* JTAG interface for debug and FLASH programming
* On-Board Power
That should be everything but the FPGA.
Now, if you can live without the FPGA being as tightly integrated into the Blackfin, you COULD pick your own board to pair with it:
http://www.digilent.us/Products/Catalog.cfm?Nav1=Products&Nav2=Programmable&Cat=Programmable%20Logic
Add both boards up. If they're stretching for affordability, I'd expect the handyboard shouldn't really be more than $400. |
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linuxguy
Joined: 16 Oct 2006
Posts: 120
Location: Beaverton, OR
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| Posted: Sat Mar 17, 2007 4:12 am Post subject: |
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| "SOI Sentinel" wrote: | linuxguy:
While this is surface mount, it's not impossible to do by hand. This is a TQFP package, so it has closely spaced leads. Shouldn't be any worse than the ATMega168, just larger. |
There is no way I want to mess with trying to solder QFN and similar type packages. I might try out Schmartboards, but that is all.
When I buy some Open Servo boards, they will be fully assembled and programmed.  After I get the rest of the SES brackets I need for The Bipod, I will be starting to get the servos for it and have them converted to Open Servos. I'm not sure whether I should go with the Hitec HS-645 (analog) or HS-5645 (digital) servos though.
I think if I was not going to use Open Servos I would opt for the 5645's. The Bipod is a hybrid biped (4DOF legs), smaller sibling to Mega Scout (8DOF legs), another hybrid biped. They are constructed using a set of modular SES subassemblies.
8-Dale
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No, Mr. Jobs, the BiPod is a ROBOT. It does not play music OR interface with iTunes.
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mpthompson
Joined: 02 Jan 2006
Posts: 650
Location: San Carlos, CA
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| Posted: Thu Mar 29, 2007 11:40 pm Post subject: |
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I just came across this $70 board from Atmel which could be a very nice Mid/Upper Level Controller for a bank of OpenServos. It is based on Atmel's "AVR32" RISC architecture, Linux operating system, 32MB of SDRAM, 16MB of Flash, two ethernet ports (a waste on a mobile robot) and an SD-Card slot.
I'll definately be looking more into this. I was interested in the BlackFin HandyBoard which has yet to ship which would be about 6x to 10x faster, but for 70 bucks this looks pretty sweet for robotics experimentation.
-Mike |
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linuxguy
Joined: 16 Oct 2006
Posts: 120
Location: Beaverton, OR
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| Posted: Fri Mar 30, 2007 12:06 am Post subject: |
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| mpthompson wrote: |
I'll definately be looking more into this. I was interested in the BlackFin HandyBoard which has yet to ship which would be about 6x to 10x faster, but for 70 bucks this looks pretty sweet for robotics experimentation. |
All I can say is if you find a source for this, please post it. I have been wanting to work with the AVR7000 chips since they came out but could not afford the STK1000 development kit. I can afford this though!
8-Dale
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No, Mr. Jobs, the BiPod is a ROBOT. It does not play music OR interface with iTunes.
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ginge
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