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Forum Index : Microcontroller and PC projects : Anyone checked these out?

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Sasquatch

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Posted: 04:51pm 21 Oct 2024
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Has anyone looked at or bought any of these?  Any thoughts or observations?

https://www.lectronz.com/products/rp2350-stamp-xl

Warning!  2mm pitch pins, not breadboard friendly!  But there is a spot to solder PSRAM on.  Hmmmm  I wonder if it will run at the higher clock speeds?  (>315MHz)

They have a carrier board with a micro-DVI port connected to the HSTX pins:

https://www.lectronz.com/products/rp2xxx-stamp-carrier-xl

Unfortunately, no audio on the carrier board.  The SD card is wired to GP8-GP11 these are serial console and audio on Peter's reference HDMIUSB design.

Seems well documented with Schematics, design files and footprints available at Github.
-Carl
 
robert.rozee
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Posted: 01:11pm 13 Nov 2024
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i've been looking at this too, a fellow is developing a PC/XT emulator that can make use of the onboard PSRAM to provide the 640k of RAM for DOS:
https://github.com/Daft-Freak/probably-average-computer-emulator

assuming the speed is enough, with just a keyboard matrix and 7" colour LCD one could then create a DIY re-imagining of the HP-200LX.

has anyone found a supplier for this RP2350 Stamp XL that is a little closer to NZ or Australia? or, indeed, has anyone successfully ordered one directly from Lectronz?


cheers,
rob   :-)
Edited 2024-11-13 23:12 by robert.rozee
 
Mixtel90

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Posted: 02:27pm 13 Nov 2024
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I see they still have no 2mm pitch plugs & sockets or flexi pins. This won't be the easiest module to work with.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Sasquatch

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Posted: 04:09pm 13 Nov 2024
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Mine arrived yesterday.  12 days economy snail-mail from Lectronz in MALMO Sweeden to Colorado USA.  I also ordered two of their "Stamp Carrier XL" boards.  My micro HDMI cables should arrive today. I should have some time to assemble and test tomorrow.  I also have some PSRAM IC's to install and test.  I don't know yet if these boards will run at the clock speeds required for the higher resolution HDMI modes.  I'll post here on TBS when I have more info to share.




Perhaps the name "Solder Party" refers to the 60 pins on the stamp XL device?  LOL
Edited 2024-11-14 02:10 by Sasquatch
-Carl
 
stanleyella

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Posted: 05:23pm 13 Nov 2024
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let us know your results please.
I don't like micro hdmi sockets. used on raspberrypi 400. full sized socket can handle thick hdmi cable.
 
Mixtel90

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Posted: 05:30pm 13 Nov 2024
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That's why you use an adapter lead. ;)
I know what you mean though. They are a necessary evil if you are short of PCB area, unfortunately.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
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stanleyella

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Posted: 06:21pm 13 Nov 2024
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  Mixtel90 said  That's why you use an adapter lead. ;)
I know what you mean though. They are a necessary evil if you are short of PCB area, unfortunately.

I was talking micro hdmi to full size hdmi lead not a standard full size hdmi lead with an adaptor plug to micro hdmi, that would be worse. they work, I would hot glue micro hdmi plug/sockets.
 
robert.rozee
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Posted: 07:36am 14 Nov 2024
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  Sasquatch said  Mine arrived yesterday. 12 days economy snail-mail from Lectronz in MALMO Sweeden to Colorado USA

how much did the postage cost end up being? i'm guessing shipping to NZ would be similar to what it costs to the US.


  Mixtel90 said  I see they still have no 2mm pitch plugs & sockets or flexi pins. This won't be the easiest module to work with

super easy, barely an inconvenience. 20 x 2mm = 40mm, vs 20 x 2.54mm = 50.8mm. so using long-pin headers (that i have several strips of) will require the outermost pins on the long edges to fan out by 5.4mm. the remainder pins working inwards will require proportionately less.

although i must admit, in reality they gained little in going for the 2mm pitch: 10.8mm reduced length, 5.4mm reduced width. it would be interesting for someone to spin an adapter board that brought the module out to an ultra-wide DIP60.


cheers,
rob   :-)
Edited 2024-11-14 17:50 by robert.rozee
 
Sasquatch

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Posted: 04:27pm 14 Nov 2024
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  robert.rozee said  how much did the postage cost end up being? i'm guessing shipping to NZ would be similar to what it costs to the US.



Economy shipping was $6.00 USD to Colorado, USA.  It was based on the weight of the items in the order.  As I recall they offered a few express shipping options, but the shipping cost quickly exceeded the value of the order.  You could always put your desired items in the cart and it will show the shipping options and cost.

I know that even economy shipping between the US and AU/NZ is extremely expensive for some reason.  Don't know anything about shipping from EU to AU/NZ.

You should probably wait to order, I will have some info on maximum clock speed as soon as I solder the "stamp" to the "carrier" later today.
Edited 2024-11-15 02:28 by Sasquatch
-Carl
 
Sasquatch

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Posted: 09:45pm 14 Nov 2024
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Ok, some initial results on the Solder Party RP2350 Stamp XL:

Device is stable at 315MHz (HDMI Resolution 640)
Seems OK at 324MHz (HDMI Resolution 1024)
Will NOT run at 372MHz (HDMI Resolution 1280)

I will do some longer term testing to verify stability at 315 and 324MHz.


Other observations:

The HDMI works fine with the default pin settings.

The SD card slot on the carrier board requires OPTION SDCARD GP9,GP10,GP11,GP8 which may require OPTION KEYBOARD DISABLE on non USB Picomite versions

The onboard LiPo charger and regulator seem to work OK.

The Official Pico2 is a great value at $5.00  but I still want a RP2350B device with more I/O pins.  The only RP2350B device that I have that runs reliably at 372MHz is the Pimoroni Pico2 Plus with the PSRAM removed.

All is not lost, I want to try the Solder Party module with my SSD1963 displays.  One of the nice things about the RP2350B is that the extra I/O pins will run a parallel LCD with plenty of I/O left over.  My best recollection is that the PicoMite firmware only supports 8-Bit parallel mode due to the limited I/O of the RP2040 device?
-Carl
 
Sasquatch

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Posted: 07:30pm 16 Nov 2024
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Quick update on the Solder Party RP2350 stamp XL with carrier board:

After more testing I am seeing some slight artifacts in the HDMI image at 1024 resolutions.  It seems to vary somewhat depending on the adapter/cable/monitor combination YMMV.  Whatever the case, the HDMI signal is marginal at 1024 resolutions.  The CPU is stable at the 324MHz, just the HDMI signal a bit marginal.  It looks very stable at 640 resolutions.

Differences to note:

1. They used 270 ohm series resistors vs 220 ohm for other designs.

2. The "Micro-HDMI" connector has tiny contacts spaced very close together and requires an adapter to full size HDMI or a micro to HDMI cable.  The video artifacts change a bit if the connector is unplugged and re-inserted.

3. There are long narrow PCB traces between the RP2350 IC and the series resistors+micro-HDMI connector.

  stanleyella said  I don't like micro hdmi sockets. used on raspberrypi 400. full sized socket can handle thick hdmi cable.


I agree!  the connector and it's contacts are tiny and fragile looking, especially with a heavy HDMI cable attached.  At least the connector has through hole mounting tabs so it's not entirely surface mounted.

Next step: add PSRAM to see if it effects maximum CPU speed.
Edited 2024-11-17 05:32 by Sasquatch
-Carl
 
Mixtel90

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Posted: 09:02pm 16 Nov 2024
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The 220R vs 270R is probably immaterial. It's merely there to limit the current from the Pico's output pins so that it can produce enough voltage. IIRC the Adafruit board also uses 270R.
Mick

Zilog Inside! nascom.info for Nascom & Gemini
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Sasquatch

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Posted: 09:13pm 16 Nov 2024
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  Mixtel90 said  The 220R vs 270R is probably immaterial. It's merely there to limit the current from the Pico's output pins so that it can produce enough voltage. IIRC the Adafruit board also uses 270R.


Both the Adafruit HDMI breakout and the HDMI sock seem to have 220 ohm series resistors.  Not sure if it really makes any difference, but something or some combination seems to limit the HDMI bandwidth.  Or perhaps it's a limitation of the RP2350B IC?  More testing needed!
-Carl
 
Sasquatch

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Posted: 09:17pm 16 Nov 2024
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Ok, finally got the PSRAM installed and working:

Added the PSRAM chip to the Stamp XL.  The Stamp XL module has the PSRAM CS line tied to GP8.  The carrier board has GP8 tied to the SD-Card CS line.  The PicoMite firmware uses GP8 for PS-2 keyboard or console by default.  

Had to cut the trace between GP8 and PSRAM CS on the XL module to get anything to boot.  Added a bodge wire between PSRAM CS and GP47.  I can hook up my el-cheapo USB microscope and take some pictures if anyone is interested.

Now it boots, and the PicoMite firmware recognizes the 8MB of PSRAM with OPTION PSRAM PIN GP47.  Haven't had much time to test the PSRAM, will need to write a small program to test.

The RP2350B still seems stable at 315 and 324MHz  with the 1024 resolution modes still a bit marginal.
-Carl
 
TassyJim

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Posted: 09:18pm 16 Nov 2024
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  Quote   They used 270 ohm series resistors vs 220 ohm for other designs.


I used 200 ohm on my rats-nest, only because I had a lot of them handy.

Stable display at all resolutions.

Jim
VK7JH
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Mixtel90

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Posted: 09:23pm 16 Nov 2024
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Possibly. I know I've seen 270R used on one module or another. It's not going to make much difference anyway.

I've abused the HSTX connections from a Pico 2 a bit and not had any problems that weren't due to a dodgy monitor. In theory the silicon inside the A and B versions of the RP2350 is identical apart from the changed mapping of the GPIO pins on the A version to make them fit the package. I suspect there's something else going on.

If you haven't had a monitor working reliably at 1080 from a Pico 2 then suspect that it may be a problem there. They won't all do it even if they will display 1080P from a DVD etc.

.
Edited 2024-11-17 07:26 by Mixtel90
Mick

Zilog Inside! nascom.info for Nascom & Gemini
Preliminary MMBasic docs & my PCB designs
 
Sasquatch

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Posted: 09:29pm 16 Nov 2024
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Here is a summary of my observations with the Solder Party RP2350 stamp XL and carrier board so far:

Things I like:

1.  Lots of I/O, although they did make some odd choices in trying to make it Arduino shield compatable?

2.  Lots of power options.  7-12V barrel jack, USB-C, single cell LiPo with onboard charger, Arduino style Headers, even the USB-A host connector could be used for power.

3.  USB-C "Device" and USB-A "Host" connectors with an anlog switch IC to connect them to the RP2350.  Can be switched by small slide switch on the carrier board or linked to GP7 via solder link on back of carrier board.  The full size USB-A "Host" connector is great for connecting a USB hub.


Things I don't like:

1.  Won't run at 372MHz for 1280 HDMI modes.  1024 HDMI modes seem marginal.

2.  Tiny Micro-HDMI connector seems inconvenient and possibly fragile.

3.  GP8 is shared between the PSRAM CS line and the SD Card CS line on the carrier board???  I had to cut the trace to PSRAM CS line and add a rework wire to GP47.  I'm not even sure if the RP2350 device can support sharing the CS line like this???  Does anyone know if CircuitPython supports this configuration?

4.  The 2mm pitch on the stamp XL is not breadboard friendly and really inconvenient for anything other than attaching it to the XL carrier board.

5.  The LiPo charge status LED flickers constantly without a LiPo cell attached.  It can be disconnected by solder link on the back of the stamp XL board BEFORE soldering the stamp to the carrier board.

All in, I'm not sure I'd really recommend the Solder Party modules for general PicoMite MMBasic use.  Peter's reference design for the official Pico2 module is still a great value AND it includes audio, RTC and USB hub.  Hopefully there will be a reference design for the RP2350B when the bare IC's become more widely available.

I still want to test with a Parallel LCD.
Edited 2024-11-17 09:21 by Sasquatch
-Carl
 
karlelch

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Posted: 07:44am 17 Nov 2024
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Hi,

I got the Solder Party RP2350 Stamp (not XL) and the carrier board.
I installed the firmware "PicoMiteHDMIUSBV6.00.00RC15.uf2"

These are the settings I use
OPTION SERIAL CONSOLE COM2,GP4,GP4
OPTION KEYBOARD GR
OPTION SDCARD GP9,GP10,GP11,GP8
OPTION AUDIO GP0,GP1


- "GR", because I use a German keyboard

- GP4 and GP5 for "SERIAL CONSOLE" are here arbitrary, it's just to move the standard serial console away from GP9 to allow for the SD card (thanks, Mick). Note that "OPTION KEYBOARD DISABLE" does not work for the HDMI/USB firmware (Syntax error).

-  GP0 and GP1 are also arbitrary, because I needed to define audio to allow Javavi's  to run (it does   )

There is a switch on the carrier board which moves the USB connection between an USB C and an USB A connector. Unfortunately, it does not "reattach" the USB C to a different UART, which would be handy. When a USB keyboard is connected to the USB A, the USB C is only for power ...

To have a serial connection to a PC in the HDMI/USB firmware, one would need to use something like an FTDI adapter to connect the board via an UART - easy doable but not out of the box.

As Sasquatch wrote, HDMI works out of the box.

In conclusion, the stamp w/ carrier allows one to test all RP2350 firmware versions, with some limits. No ideal choice for game programming (e.g., audio and serial link would need to be added). For robotics, it is probably o.k. (charger, some connectors preinstalled, SD card, w/ stamp XL, many more pins than with the "small" RP2350). In the end, it is maybe just a test board  

Best
Thomas
 
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