AdRiley
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Re: Gertboard

Sun Jan 08, 2012 8:15 pm

Jongoleur said:

Then you could text your garage door to be open by time you get home!




Better still have a second RasPi in your car with GPS to open the garage door when the car gets close to home.


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Gert van Loo
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Re: Gertboard

Sun Jan 08, 2012 10:28 pm

SeanD said:


Gert, you know how when you get to the end of a Youtube it show you recommendations?  How come this one for a Zomie Killing Slingshot is connected to the Gertboard?

http://www.youtube.com/watch?f.....240YgsA_rs



I am new to you tube. That was my first video ever. I have no idea where that comes from or how to change iit. So Im open for suggestions how to improve/correct it....

Tomo2k
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Re: Gertboard

Mon Jan 09, 2012 2:06 am

Excellent!

(Some of the tracks on the PCB look a bit random – are there really several that are completely unconnected or am I just being thick or blind?)

Very good idea to switch out the buffers for ADC/DACs instead, that is much more useful.

Is the PIC wired up for low-voltage programming?

That or something to let us bootstrap the PIC direct from the RPi with no extra components at all would be great, even if we have to move a few jumpers to permit the bootstrapping.

Actually, which PIC did you go with?

Joules
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Re: Gertboard

Mon Jan 09, 2012 3:06 am

You do know the pcb is double sided and that some tracks have interconnects to the opposite side. Other than that a few end where surface mount components go. I haven"t seen any random tracks???

Then again !!! The short tracks could be usefull for prototyping busses.

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Gert van Loo
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Re: Gertboard

Mon Jan 09, 2012 8:18 am


(Some of the tracks on the PCB look a bit random – are there really several that are completely unconnected or am I just being thick or blind?)


You are probably seeing the copper fill tracks. I put some copper 'stripes' down in areas which have nothing to get a better result when etching.You see, if you have areas with thin tracks next to large areas with no tracks the thin tracks can get eaten away. I think they call it 'copper balancing'.

Some PCB companies can do that for you and you get nice little square rectangles. As the Gerbers will be made public I have no idea who will produce these so I put some filler metal in myself. The tracks on this board are relative wide(0.254 inch) so should be OK. But better safe then sorry.

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Jongoleur
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Re: Gertboard

Mon Jan 09, 2012 4:26 pm

Someone told /. about the GertBoard….

http://hardware.slashdot.org/s.....-in-action

*sigh*

Some of the comment is thoughtful, but the rest is really not worth looking at.
I'm just a bouncer, splatterers do it with more force.....

Tomo2k
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Re: Gertboard

Mon Jan 09, 2012 4:53 pm

Gert said:



(Some of the tracks on the PCB look a bit random – are there really several that are completely unconnected or am I just being thick or blind?)


You are probably seeing the copper fill tracks. I put some copper 'stripes' down in areas which have nothing to get a better result when etching.You see, if you have areas with thin tracks next to large areas with no tracks the thin tracks can get eaten away. I think they call it 'copper balancing'.


Ah yes, that makes perfect sense.

I tend to do a ground plane flood fill on two-sided boards, but striped fill tracks will work just as well - maybe better.

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Re: Gertboard

Mon Jan 09, 2012 5:30 pm

Jongoleur said:


Someone told /. about the GertBoard….

http://hardware.slashdot.org/s.....-in-action

*sigh*

Some of the comment is thoughtful, but the rest is really not worth looking at.


Didn't think that was too bad for Slashdot. Usual Broadcom haters, but otherwise not too insane!
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Gert van Loo
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Re: Gertboard

Wed Jan 11, 2012 4:19 pm

PIC compatability.

I have had questions about which PIC is on the Gertboard. I am using 18F26K20 but I just found a pin-compatibility document from Microchip. According to that you can use all of the following 28-pin PIC devices:

PIC16C62B PIC16F767* PIC18F2331
PIC16CR63 PIC16F870* PIC18F2410
PIC16C63A PIC16F872* PIC18F2420
PIC16C642 PIC16F873* PIC18F2431
PIC16C66 PIC16F873A* PIC18F2455
PIC16CR72 PIC16F876* PIC18F2480
PIC16C72A PIC16F876A* PIC18F2510
PIC16C73B PIC16F913* PIC18F2515
PIC16C745 PIC18C242 PIC18F2520
PIC16C76 PIC18C252 PIC18F2525
PIC16C773 PIC18F242 PIC18F2550
PIC16F57 PIC18F248 PIC18F2580
PIC16F72* PIC18F252 PIC18F2585
PIC16F73* PIC18F258 PIC18F2610
PIC16F737* PIC18F2220 PIC18F2620
PIC16F76* PIC18F2221 PIC18F2680
PIC18F2320
PIC18F2321
* PGM for PIC16FXXX devices is located on pin 24.

Tomo2k
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Re: Gertboard

Wed Jan 11, 2012 4:44 pm

Thanks Gert!

Bootstrapping a "brand-new blank" chip is possible then, as I believe all of these ship with Low-Voltage ICSP enabled by default (PGM not available as a GPIO).

Certainly the PIC18F26K20 does.

- The user would also have to get VIHH (8-9V) onto the chip to disable LVP and make RB5 available, which is good, as it makes it harder for an end user to break!

So this "just" needs someone to port over one of the existing Linux PIC programmer tools!

As I have no experience of any Linux PIC ICSP programming tools, does anyone have a suggestion for a decent open-source one?

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Gert van Loo
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Re: Gertboard

Thu Jan 12, 2012 8:08 am

Scrapping Rev-1 Gertboards.

I was just about to throw my remaining  12-ish Rev-1 printed circuit boards in the bin when I though there may be people out there who would love to get their hands on one despite the numerous errors which are on them.

There are a number of issues with that:


I am very busy and I don't have time to put them on EBay (I don't even have an EBay account), sell them, check the money, ship etc. I emailed Liz and she is happy with my proposal and they will be sold through the Raspberry-Pi organization.
You have to have good knowledge of electronics as they will only be accompanied by the schematic and a list of what I found was wrong with them. No manual, no assembly instructions, no parts list etc.
To emphasize that this is different from the Prototype auction there will be a maximum price. I was thinking around £20-£30 ish. (I don't know how EBay works, I assume there is an option for that).The money will go to the organization as they have to be compensated for the handling, shipping etc. of such a small series.

I have no idea when they will be for sale. Liz and Eben are away but this may be handled by somebody esle in the organisation. If not we have to wait or them to be back.

-- Gert

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meltwater
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Re: Gertboard

Thu Jan 12, 2012 8:41 am

You can sell with a buy-it now option, which just sells for a fixed price, so no problem with that.

I expect they won't be around for long, but glad they didn't hit the bin.
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Re: Gertboard

Thu Jan 12, 2012 11:18 am

nothing - no prototype should be binned and i think these should be put up for sale, i do agree about the fixed price though.

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meltwater
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Re: Gertboard

Thu Jan 12, 2012 11:26 am

Could even post one off the to computer museum too, to help add to their collection...
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Gert van Loo
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Re: Gertboard

Thu Jan 12, 2012 12:09 pm

mightygoose said:


nothing - no prototype should be binned and i think these should be put up for sale, i do agree about the fixed price though.



I was not planning to bin the prototypes. Just another 12 bare PCBs I still have.

(The manufacturer charged only £10 more for 15 boards then for 4 boards, hence I ordered 15 in the hope that there were no too many changes. So now I have 12 spares...)

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Burngate
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Re: Gertboard

Thu Jan 12, 2012 12:54 pm

Great. My cheque's almost in the post - needs the amount, and who to make it out to!

Bluemerlin
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Re: Gertboard

Thu Jan 12, 2012 2:14 pm

Burngate said:


Great. My cheque's almost in the post - needs the amount, and who to make it out to!


Your Cheque seems to be in the same state as mine

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meltwater
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Re: Gertboard

Thu Jan 12, 2012 2:20 pm

You are both very welcome to make them out to me and send them off if you like (and I'm not even a prince or ever been to Nigeria…).  :)
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Re: Gertboard

Sat Jan 14, 2012 5:46 pm

Dropping PIC.

I just tried for eight hours to build an SPI interface between the Raspberry-Pi and the PIC. I have not been able to exchange data. So I have come to the conculsion that the PIC is not suited and I plan to replace it with another micro controller.

Any suggestions?

lyzby
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Re: Gertboard

Sat Jan 14, 2012 6:11 pm

>Any suggestions?

PICAXE

Already used in education in UK and elsewhere, great, tirelessly helpful forum (http://www.picaxeforum.co.uk/forum.php), accessable via serial (or I2C for X2 versions), easy control of i/o, motors, etc.

The main drawback would be that they would have to be programmed with a separate computer.  At this time, there is a linux compiler available, but only for x86, not ARM.  Perhaps they could be pushed in the ARM direction by Raspberry Pi.

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meltwater
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Re: Gertboard

Sat Jan 14, 2012 6:22 pm

Arduino?  Runs for cover...

Wish I could suggest one in particular...what features of the PIC was it you were after?  I can look up what we use over SPI on our projects if it's just the multichannel ADCs...unfortunately not a H/W engineer so although willing probably not much help.

The TI MSP430's as used by the Launchpad going to be much different (programmer etc cheap)?
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Re: Gertboard

Sat Jan 14, 2012 7:23 pm

I wanted to add a micro controller to let pupils experience a  'blank computer'. So they have to set up a UART in order to have any I/O. Play with a timer and it's interrupts. Then change the UART drivers to work under interrupts (With a SW FIFO queue for transmit and receiver) the works.

Bakul Shah
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Re: Gertboard

Sat Jan 14, 2012 7:42 pm

How about one of the ATtinys? tiny85 has 8 pins so probably too constrained but there are other models with more pins (and less multiplexing). A few channel of 10 bit a/d, pwm, timer/counters, SPI etc. May be socketed (would be neat if it can be used to program tiny85 etc. for other projects).

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Chromatix
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Re: Gertboard

Sat Jan 14, 2012 8:19 pm

The HC08 series is probably worth looking at.  The lower-end models are very cheap and are self-clocked, and it should be easy enough to program them from the R-Pi end.

The machine code they use is not too dissimilar from 6502.
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mr_x007
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Re: Gertboard

Sat Jan 14, 2012 8:33 pm

meltwater said:


Arduino?  Runs for cover…


That could actually work, just use a atmega 328, it has all the needed peripherals and if you load the boot loader you can use arduino programs, but if you don"t you can just use plain C or assembly, it"s kinda the best of both worlds….

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