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Topic: Bus Pirate v4 hardware  (Read 72080 times) previous topic - next topic

Re: Bus Pirate v4 hardware

Reply #30
[quote author="ian"]
I was joking about the easter egg :) I like it a lot. If only someone would find it I can stop littering every post with clues :)
[/quote]

The first person that send me 100U$ will receive the directions to the easteregg :P

:X

Re: Bus Pirate v4 hardware

Reply #31
I noticed the two new AUX connection don't have (selectable) pullups. Will they have this in the final design or is this by design?

I think they are 5V tolerant though.

Re: Bus Pirate v4 hardware

Reply #32
This is by design. The existing AUX pin doesn't have a pullup either. If there was room we could add another 4066 for all 3 aux pins, but I'm not sure where to put it.
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Re: Bus Pirate v4 hardware

Reply #33
I think when moving all the resistors (between the pic and header) and current 4066 a bit up, loose the reset switch (not needed in the final design??) you can fit it there (don't know if it is routable, but should be). Using resistor arrays will give also extra room. Reset button could move to the left of the icsp if you want to keep it.

I hope you already send the current board to the pcb fab house :X

Re: Bus Pirate v4 hardware

Reply #34
Hi guys,

I'll try to add the 2nd 4066 on the board.

Re: Bus Pirate v4 hardware

Reply #35
Can Seeed do 0402 parts? We could save a lot of room, but at a cost of half the power capacity. : /
 - Adam

Re: Bus Pirate v4 hardware

Reply #36
Actually a bigger board won't cost (very much) extra. I guess it is a male thing to let size matters ;)

I also like to have resistors and capacitors I like to see and can solder with a regular iron (remember that it is an enginering prototype!!) I hope I can solder the pic ;]

Re: Bus Pirate v4 hardware

Reply #37
Hello,

here's the board I made.
a couple modification on the wiring though
-swapped ADC3 and ADC4
-swapped PUVSEL33 and PUVSEL50

sorry for the delay

/V

Re: Bus Pirate v4 hardware

Reply #38
Nice :) I sent the update to the board house already, but we can send this one next week if anyone would like to test it too.
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Re: Bus Pirate v4 hardware

Reply #39
Just one question:

Why stick with PIC24 series for Bus Pirate 4 ?

why not switch to dsPIC33 ?  they have more RAM and better peripherals (especially PWM for motor control). For the price, I think that now that  Bus Pirate has made its proofs, so I think that users will accept to pay 3 or 4 more $$ to have a dsPIC instead of a PIC24.

regards

Re: Bus Pirate v4 hardware

Reply #40
Developers were persuaded to consider an integrated USB solution, and there are no integrated USB dsPICs:
http://www.microchip.com/ParamChartSear ... &pageId=74
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Re: Bus Pirate v4 hardware

Reply #41
I think that integrated USB is a very bad choice!
think about timing and usb state machine. You need to poll usb in less than 10ms each time. Some developpers use an interrupt to do that, but this is not a solution.
BusPirate should evolve in a way that it can provide better signals timing possibilities. Having to support USB is a problem.
All firmware should be written arround USB state machine, this means more constraints for less profit. I think that we could even split the desing of BusPirate in two separate modules,
1- one module that will be BusPirate signals and protocols handling,
2- and one module for data transfert from/to PC.

This second module can be:
- either USB based (FTxxxx),
- or Ethernet based which is (for me) a better choice because any PC on the lan can control BP, and any PC can control any number of BP on the Lan (we ca also do distant logging on internet),
- or either simply an UART (without tranceiver) based ... this will make it possible to pilote  BusPirate using handheld devices or some small industrial PC-104 boards like the  mini2440 ARM based board
http://www.friendlyarm.net/sites/produc ... 2440_2.jpg
http://www.friendlyarm.net/sites/produc ... 440-35.jpg

Regards

Re: Bus Pirate v4 hardware

Reply #42
I certainly understand. As I said, we were persuaded. I was dead set against porting the Bus Pirate to a giant state machine, and enumerated all these reasons myself (plus VID/PID, and lack of open source USB firmware). Could you elaborate on why an interrupt is not a solution?

If timing is a consideration for you, don't look at the Bus Pirate signals on a logic analyzer, it's already totally unreliable because it has to push stuff up a slow UART. Really sensitive stuff, like PWM or frequency measurement, is hardware based and won't generally be effected by the USB service routine.

The Bus Pirate with a UART connection does not provide enough speed for a lot of the apps that support it, the biggest complaint is always speed and never timing.
The v3 with FTDI chip will remain available when v4 is for sale, so you still have the option of a non-USB Bus Pirate.

Really, we don't even know if it's going to happen. Tons of people have pushed for an integrated USB Bus Pirate, but nobody has coughed up any code to support it or anything. We're going to make a batch of prototype hardware for anyone that wants to mess with it, but that's as far as we're committed now.
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Re: Bus Pirate v4 hardware

Reply #43
[quote author="ian"]
Could you elaborate on why an interrupt is not a solution?
[/quote]

Cause if you use Software protocols implementation for example like  I2C (to be able to strech signals or avoid hardware bugs), you'll need to take into account the usb polling (in the interrupt) ...
Software timing will become really a night mare to handle in ALL protocols. (why FPGA developpers always use an external chip for USB instead of implementing it in the FPGA?)
Understand me, I dont say it's not feasible (as most usb programmers works this way) but the profit from using an USB chip is really not that important! Development effort will become more important for very little profit ... and all you'll win in price, you'll lose it paying for VID/PID licenses (considering the production volume you're doing).

[quote author="ian"]

The Bus Pirate with a UART connection does not provide enough speed for a lot of the apps that support it.
[/quote]
On PC104 boards you can got UARTs at up to 2MB .... enought for logging slow I2C data  ;) 
When you use a BusPirate to spy an I2C bus that have very low traffic (only few bytes each 10 min) you dont need too much band width.

[quote author="ian"]
We're going to make a batch of prototype hardware for anyone that wants to mess with it, but that's as far as we're committed now.
[/quote]
I personally used USB only with PIC18 series (and with STM32). If you think you will be going this direction in BP4, I can help. But right now, I used only Microchip USB stack. I never looked for a free usb stack for Microchip mcu. If you have already took decisions about anything related to that, let me know, I'll be glad to help on that.

Regards

Re: Bus Pirate v4 hardware

Reply #44
Afaik there are more interrupts involved into USB communication then just a timer interrupt every 10ms. All USB transactions (the handling of endpoints) is done in hardware, and the hw automatically stalls if an endpoint is full.

This new PIC also has no issues with broken hardware, like I2C on some revs of the current used chip. So most of the protocols are handled in hardware now. Besides this most protocols aren't timesensitive and also synchron.