Home
JAQForum Ver 20.06
Log In or Join  
Active Topics
Local Time 23:11 02 May 2024 Privacy Policy
Jump to

Notice. New forum software under development. It's going to miss a few functions and look a bit ugly for a while, but I'm working on it full time now as the old forum was too unstable. Couple days, all good. If you notice any issues, please contact me.

Forum Index : Microcontroller and PC projects : PicoMite VGA Edition PCB - release version

     Page 2 of 6    
Author Message
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 02:43am 20 Apr 2022
Copy link to clipboard 
Print this post

From the BOM
  Quote  Q1, Q2 n-channel enhancement mosfet, max GS threshold 2V
Tested with BST72A and silkscreen matches this part. Suggest TN0702N3-G Farnell 2920846 £1.25 = £2.5 (check pinout against silkscreen)


Farnell/Element14 dont seem to stock either of these parts anyone found a suitable replacement.
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
al18
Senior Member

Joined: 06/07/2019
Location: United States
Posts: 175
Posted: 02:52am 20 Apr 2022
Copy link to clipboard 
Print this post

Mouser has over 3000 in stock in the US
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 03:21am 20 Apr 2022
Copy link to clipboard 
Print this post

The freight from USA to Australia is too much. $20 or more.

I can probably source a SMD device that I could solder in, I haven't checked yet
just thought someone may have a through hole replacement.
Edited 2022-04-20 13:24 by palcal
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
Turbo46

Guru

Joined: 24/12/2017
Location: Australia
Posts: 1593
Posted: 03:29am 20 Apr 2022
Copy link to clipboard 
Print this post

2n7000 can be used. Altronics and Jaycar both have them but note the orientation is different.

Bill
Keep safe. Live long and prosper.
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 03:34am 20 Apr 2022
Copy link to clipboard 
Print this post

Thanks, Bill.
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 04:43am 28 Apr 2022
Copy link to clipboard 
Print this post

I ordered the SD card breakout board from Element14/Farnell part no. 279-9953
It is different to the one shown in the photos. I can't read the silk screen on matherp's photo and the scematic in the ZIP file is .sch format that I can't open.
Here is a picture of what I have. I think I will have to offset it but do the pins match up. There was no photo on the Element14 site so I was flying blind.



Edited 2022-04-28 14:48 by palcal
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3551
Posted: 05:53am 28 Apr 2022
Copy link to clipboard 
Print this post

Hi Pascal,

Your sd card board is capabele of 5v. The board that Peter designed is 3.3v
So you have the wrong board.
But you may be able to get it to workshop by tying 5v and 3.3v pins together to 3.3v.
And you may have to swap pins in the Option sd card definition.

Volhout
PicomiteVGA PETSCII ROBOTS
 
Turbo46

Guru

Joined: 24/12/2017
Location: Australia
Posts: 1593
Posted: 05:54am 28 Apr 2022
Copy link to clipboard 
Print this post

I got the one specified from Core Electronics.

The pin layout is different and yours has a voltage regulator and level shifting which are not needed for Peter's board. There is a datasheet on the Element14 site for info on the one you have.

Bill
Keep safe. Live long and prosper.
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 07:55am 28 Apr 2022
Copy link to clipboard 
Print this post

I have an account at Core Electronics will order from them.
Thanks
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
Chopperp

Guru

Joined: 03/01/2018
Location: Australia
Posts: 1032
Posted: 08:25am 28 Apr 2022
Copy link to clipboard 
Print this post

Out of stock at CORE ATM

Did you get the last one?
.
Edited 2022-04-28 18:27 by Chopperp
ChopperP
 
Amnesie
Guru

Joined: 30/06/2020
Location: Germany
Posts: 382
Posted: 08:35am 28 Apr 2022
Copy link to clipboard 
Print this post

  Volhout said  Hi Pascal,

Your sd card board is capabele of 5v. The board that Peter designed is 3.3v
So you have the wrong board.
But you may be able to get it to workshop by tying 5v and 3.3v pins together to 3.3v.
And you may have to swap pins in the Option sd card definition.

Volhout


I am using this Adafruit Sd Breakout on ALL my picoMite builts. It works perfectly with 5V directly, since it has own level shift but it also works via 3V3 on the corresponding pin. In my opinion this is the ultimate breakout because it is ready for every voltage. Of course it is a slightly different pinout than the black (3v3 only) version for which the original picoMite VGA PCB was desigend for.

So in short: the Adafruit blue version does work, but it won't fit the pinout on the board.

Greetings
Daniel
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 07:03pm 28 Apr 2022
Copy link to clipboard 
Print this post

Yes must have got the last one.
@ Amnesie, thanks for that at least it is not a loss.
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3551
Posted: 08:35pm 28 Apr 2022
Copy link to clipboard 
Print this post

Pascal, I was impatient....


PicomiteVGA PETSCII ROBOTS
 
palcal

Guru

Joined: 12/10/2011
Location: Australia
Posts: 1804
Posted: 08:43pm 28 Apr 2022
Copy link to clipboard 
Print this post

I think we have all done wiring like that at some time.
Edited 2022-04-29 06:45 by palcal
"It is better to be ignorant and ask a stupid question than to be plain Stupid and not ask at all"
 
Turbo46

Guru

Joined: 24/12/2017
Location: Australia
Posts: 1593
Posted: 11:27pm 28 Apr 2022
Copy link to clipboard 
Print this post

One way to use a different breakout would be to make a carrier board out of strip board which will fit the mounting for the specified board and fit the alternative board on top of that with the cross patching done on the strip board. That will allow you to fit the correct one later if you want.

Bill
Keep safe. Live long and prosper.
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3551
Posted: 07:41pm 03 Jun 2022
Copy link to clipboard 
Print this post

  robert.rozee said  so the layout (looking into the connector from the front) is something like the below?

   (1)          (2)  
   GP0   x  x   GP1
   GND   x  x   GP2
   GP3   x  x   GP4
   GP5   x  x   GND
   GP6   x  x   GP7
   GP8   x  x   GP9
   GND   x  x   GP10
  GP11   x  x   GP12
  GP13   x  x   GND
  GP14   x  x   GP15
  GP16   x  x   GP17
   GND   x  x   GP18
  GP19   x  x   GP20
  GP21   x  x   GND
  GP22   x  x   nRST
  GP26   x  x   GP27
   GND   x  x   GP28
ADCREF   x  x   3v3
 3v3EN   x  x   GND
  VSYS   x  x   VUSB
  (39)          (40)


cheers,
rob   :-)



I think I am confused. When I look at the board layout in the first post of this thread, I can clearly see that 3.3V is routed to pin 25 (or 26 when the pin numbers are mirrored). In this drawing it is on pin 36. Is the board layout in the first post not the last layout ?
PicomiteVGA PETSCII ROBOTS
 
matherp
Guru

Joined: 11/12/2012
Location: United Kingdom
Posts: 8592
Posted: 09:34pm 03 Jun 2022
Copy link to clipboard 
Print this post

  Quote  I think I am confused.


No, you have spotted a complete f-up that for reasons unknown nobody else has seen before. Pins 21-40 are all completely wrong on the edge connector. I'll post a revised version once I fix it
 
Volhout
Guru

Joined: 05/03/2018
Location: Netherlands
Posts: 3551
Posted: 07:37am 04 Jun 2022
Copy link to clipboard 
Print this post

Peter,

Not sure if it pays off to change the board layout in this phase, unless you have other reasons to do so. Maybe we should just document what it is, and leave it at that. The early adopters all have this version. And it is unsure how many will build the new version and throw away the old. So you end up with a mix best case. Or you spend a lot of time and no-one uses it.
It feels a bit like the CMM2 revision 1 and revision 2 incompatibility.
PicomiteVGA PETSCII ROBOTS
 
robert.rozee
Guru

Joined: 31/12/2012
Location: New Zealand
Posts: 2290
Posted: 08:29am 04 Jun 2022
Copy link to clipboard 
Print this post

i believe there are already multiple 40-pin connector pin layouts for the various pico carrier boards.


cheers,
rob   :-)
 
JohnS
Guru

Joined: 18/11/2011
Location: United Kingdom
Posts: 3661
Posted: 10:27am 04 Jun 2022
Copy link to clipboard 
Print this post

I'm confused too - what is the layout for the current connector?
(on Peter's board)

John
 
     Page 2 of 6    
Print this page
© JAQ Software 2024