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Topic: What breakout do you need/want? (Read 105427 times) previous topic - next topic

What breakout do you need/want?

We recently added a breakout board to our portofolio and we have some more to come:

- MMA7455L 3-axis accelerometer (released)
- MCP2200 USB-to-serial with GPIO (soon to come)
- FT2232H hispeed usb-to-serial with GPIO (soon to come)

In the MMA7455L thread several users suggested other chips to breakout:

- I2C/SPI sensors, ADC/DAC, memory (IPenguin)
- accelerometer/gyro combo (serial interfaced) (Arhi)

So I guess you want DangerousPrototypes to develop some more breakoutboards. We like to hear which chip(s) you like to see on a handy PCB. These are on my wish list:

- display + buttons (every project needs an userI/O)
- CPLD/FPGA (to quickly come up with logic you don't have in your scrapbox)
- camera

What do you want to breakout?

Re: What breakout do you need/want?

Reply #1
CPLD! ... with McBSP serial interface over 16-pin Hirose (*)
Well, I wouldn't mind if it also has SPI or I2C.  ;-)

(*) The 16-pin Hirose would interface to a TMS320VC5506 board that I designed.  It's a custom pinout that also feeds power to an 8-channel AD.  If you do design a CPLD/FPGA breakout, drop me a line and I'll try to squeeze my connector on there somewhere - hopefully it won't make the desired size impossible.

Re: What breakout do you need/want?

Reply #2
[quote author="rsdio"]
CPLD! ... with McBSP serial interface over 16-pin Hirose (*)
Well, I wouldn't mind if it also has SPI or I2C.  ;-)

(*) The 16-pin Hirose would interface to a TMS320VC5506 board that I designed.  It's a custom pinout that also feeds power to an 8-channel AD.  If you do design a CPLD/FPGA breakout, drop me a line and I'll try to squeeze my connector on there somewhere - hopefully it won't make the desired size impossible.
[/quote]

You got any cpld particular in mind?

I have somewhere an untested design for a 74xx logic emulator based on the xc9572xl. it has a .3" DIP20 footprint for breadboarding. I designed it to replace 74xx and 4xxx digital chips and not as generic cpld board. I was inspired by this topic: http://dangerousprototypes.com/forum/in ... 61#msg7661

Edit: how about the XC2C32A (the one used in the busblaster v2 update)?

Re: What breakout do you need/want?

Reply #3
XC2C32A is only 3v3, but a very cheap and plentiful chip. probably a xc2c256 would be better, so you have enough marcocells to actually do something.
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Re: What breakout do you need/want?

Reply #4
Is 3v3 a problem nowadays?

I don't have a clue what you can do with one macrocell :) It looks like fun to start with cpld though.

Re: What breakout do you need/want?

Reply #5
I don't think so, but a lot of people still see 5v as a requirement. Bus blaster v1 is 3v3 on,y, as is v2, but that doesn't bother me. I think for the universal logic chip maybe a lot of people want to use it kith arduino and prefer 5volts though. Doesn't matter yo me either way, ibhave both chips already ;)

This post includes free iPadisms :)
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Re: What breakout do you need/want?

Reply #6
Luckilly it has some buffer chips to cope with that ;)

It uses the TXB0108PW buffer chip. That is a bi-directional bufferchip that will convert a low voltage (a-side) to a higher voltage (b-side). the cpld is connected to the a-side (running at 3v3) the remaining at the b-side (3v3 - 5v).

Re: What breakout do you need/want?

Reply #7
[quote author="Sjaak"]
It uses the TXB0108PW buffer chip. That is a bi-directional bufferchip that will convert a low voltage (a-side) to a higher voltage (b-side). the cpld is connected to the a-side (running at 3v3) the remaining at the b-side (3v3 - 5v).
[/quote]

Careful with those, if you happen to have pullup and want to pull it down with the buffer chip, you might not reach the logic 0 voltage limit. I had this problem on one of my board. I was using the MAXxxxx equivalent to this buffer.

Re: What breakout do you need/want?

Reply #8
[quote author="Sjaak"]You got any cpld particular in mind?[/quote]I'm thinking of a project from the OpenCores site that needs "only" 39 macrocells with register width of 5.  This seems to rule out the XC2C32A, though.

Frankly, I could probably just use the OLS as a platform for doing this with FPGA, but the idea of a breakout board that might plug directly into my DSP board is tempting.

In any case, it should probably be a CPLD/FPGA that is already being purchased in bulk for another Dangerous Prototype.

Q: Does FPGA simply imply hundreds to thousands more cells than CPLD?

[quote author="ian"]
... a lot of people still see 5v as a requirement. ... I think for the universal logic chip maybe a lot of people want to use it kith arduino and prefer 5volts though.[/quote]3.3V is fine with me, too, especially for optical I/O (where the voltage isn't even the point anyway).  I think perhaps 5V is more useful when you want to be able to interface with random other circuits.  If you're doing a single, dedicated design, then it seems like you can just use 3.3V chips for everything and keep it simpler.  In any case, designs which only use 3.3V are far easier to implement on the USB platform.

If you actually need 5V, but you don't have a boost regulator, then the >= 4.01V USB supply will not always meet the 4.75V minimum anyway.  Adding the boost regulator isn't that hard, since some designs only require three capacitors and a single chip, but that does add to the minimum cost.

Re: What breakout do you need/want?

Reply #9
Well the goal is to make interesting breakout boards :) we don't have a large pile of components nor do we produce our stuff with 1000s a time, so any cheap *) CPLD/FPGA would do the trick..

I guess the ft2232 + cpld is already a kind of 'breakout board' for the xc2c32a, and the logic sniffer is also a 'breakout board'. But personally I like a 'small' footprint for a breakout board. (with fpga there is no such thing as small ;))

*) cheap = a price attractive to hobyists, which is I guess is max 5-10$ for the chips and a little more for sensors.

Re: What breakout do you need/want?

Reply #10
[quote author="Sjaak"]
*) cheap = a price attractive to hobyists, which is I guess is max 5-10$ for the chips and a little more for sensors.
[/quote]

Definitely! One reason that I only use Sparkfun for their tutorials is because their breakout boards are pricey.

Re: What breakout do you need/want?

Reply #11
That price is without the actual board, components, headers, manufacturing etc. That will add up to the price.

Re: What breakout do you need/want?

Reply #12
Of course it will add. But look at this: The breakout for FT232RL is $14.95 while the IC itself is only $3.95! This is why I say pricey.

Re: What breakout do you need/want?

Reply #13
The ic is four bucks in onside too, they gotta get them between one and two bucks.
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Re: What breakout do you need/want?

Reply #14
imho, if they want to charge their boards a mil they can, they have their own idea on what and why they are doing ... so we might concentrate on "what's missing" rather then "why is spark..."

the 2 major reason ppl get breakboards
 - chips that are hard to solder
 - chips that require a lot of external components

the first one is pretty obvious, and the harder the chip to solder (those legless chips, or micron pitch ones) the more likely is that anyone will decide to go for a breakboard... the second one is also important aspect, it is super cool to have max232+all the caps in smd on a 1x1cm board that you can use to get serial comm to any of your projects in a second ... or a 2A bipolar stepper driver with all the stuff on the board (for e.g. this board, I purchased already more then 20!! and all my friends from reprap project, I think they bought hundreds of those .. even more ..) or some of the mikroe's boards ... I know why they are expensive (they make them locally and when you phd's soldering your boards they tend to be expensive + export taxes, shipping etc - very expensive in this god forsaken country) but check some of the ones I really like
http://www.mikroe.com/eng/products/view ... eth-board/
http://www.mikroe.com/eng/products/view ... oto-board/
http://www.mikroe.com/eng/products/view ... 32-boards/
http://www.mikroe.com/eng/products/view ... t-2-board/
http://www.mikroe.com/eng/products/view ... oto-board/

all of these can be "better" (max232 can be smaller if smd is used and most of others too) and should be made a lot cheaper ..