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What do you think is the best hand-solderable application processor these days? I don't see any non-BGA I.MX6 chips, but I didn't look very hard. Is the hobbyis

What do you think is the best hand-solderable application processor these days? I don't see any non-BGA I.MX6 chips, but I didn't look very hard. Is the hobbyist stuck with an ARM926? Also, in that vein, is there a similar solution for I.MX23's?

planteen 9y ago
You can get a i.MX6 SoM (system-on-module) to take care of nasty things like external memory. https://www.solid-run.com/freescale-imx6-family/imx6-som/ https://www.solid-run.com/freescale-imx6-family/imx6-som/
- psykotic 9y ago
  I was about to suggest SoMs as well. The biggest challenge with BGAs from a hobbyist perspective isn't the soldering. There are lots of hobbyists successfully reflowing BGAs with toaster ovens. The bigger problem is manufacturing the PCBs to break out the BGA balls. TI has some BGAs with a proprietary ball pattern that are designed to be broken out with just 4 layers, but that's the exception, and you generally need very narrow traces and trace clearance to route between balls and vias. I just looked at OSH Park's current capabilities and they only do up to 4 layers and their DRC specifies 6 mm minimum trace width and 6 mm minimum spacing. I've heard of people using OSH Park and similar lower-end prototyping services to manufacture one-off PCBs for fine-pitch BGAs, but you'll be failing DRC by a massive margin, so expect terrible yield on the PCBs, assuming any of them work at all. Unfortunately I think DRC will be similarly challenging for most SoM connectors since their pin spacing has a similar pitch to BGAs, so you'll probably need an off-the-shelf break-out board to work around that. Honestly, at some point you should consider whether a vanilla dev board with low-speed GPIO headers could meet your requirements.
  - leggomylibro 9y ago
    Those OSHPark rules are 6mil, not mm - that's a little over 0.15mm. But it's still not really suitable for BGP modules. You can probably do 60-ball RAM modules, but a medium-sized processor seems like it would be off the table. I think that dirtyPCBs does 6-layer boards, but they're comparatively pricey for small runs or prototypes.
    - psykotic 9y ago
      Thanks for the correction; I thought 6 mm sounded way too high. Gotta love American measurement units! There are Internet accessible Chinese PCB manufacturers that will do short runs for designs of almost any complexity, but they aren't really targeting hobbyists, though that seems to be changing.
      - leggomylibro 9y ago
        Yeah, mils are a really strange measurement unit. I'm not sure who thought that 1/1000" would be a good standard.
        semi-extrinsic 9y ago
        I think it harks back to older manufacturing processes, via plastics (where mils are used) back to metalworking. Machinists will usually talk about small distances in "thou", as in thousandths of an inch. Always cracks me up when AvE mentally converts 2.5/64" or some crazy shit into thou while thinking out loud, and then goes "metric fanboys be like whaaat?"
- leggomylibro 9y ago
  Huh, I hadn't heard of that sort of thing, besides the various dev boards offered by the microprocessor developers. Thanks!
robert_foss 9y ago
I'm hardly an electronics designer (although I do it for fun), so I don't have much of an opinion. However, I don't think there are any SOCs with Adreno or Vivante GPUs that are also hand solderable. A quick Octopart search[1] turned up nothing. About iMX23, a quick look seems to suggest that it has no 2D/3D capable IP on the SOC. So it likely just has a display controller of some sort. Unfortunately I don't know what that display controller is. It may be encompassed by the imx driver depending on that the hardware actually is. [1] https://octopart.com/search?q=&start=0&category_ids=4267&specs2.2.values=LQFP&specs2.2.values=TQFP&specs2.2.values=QFN&specs2.2.values=QFN%20EP&specs2.2.values=QFP&specs2.2.values=VQFN https://octopart.com/search?q=&start=0&category_ids=4267&spe...
jdboyd 9y ago
The AllWinner A13 (Cortex A8) is available in a LQFP176 package. That includes a MALI400 GPU. That is still fairly old, but more up to date than ARM926.
- deleted 9y ago
  [deleted]

planteen 9y ago

You can get a i.MX6 SoM (system-on-module) to take care of nasty things like external memory. https://www.solid-run.com/freescale-imx6-family/imx6-som/ https://www.solid-run.com/freescale-imx6-family/imx6-som/

psykotic 9y ago
I was about to suggest SoMs as well. The biggest challenge with BGAs from a hobbyist perspective isn't the soldering. There are lots of hobbyists successfully reflowing BGAs with toaster ovens. The bigger problem is manufacturing the PCBs to break out the BGA balls. TI has some BGAs with a proprietary ball pattern that are designed to be broken out with just 4 layers, but that's the exception, and you generally need very narrow traces and trace clearance to route between balls and vias. I just looked at OSH Park's current capabilities and they only do up to 4 layers and their DRC specifies 6 mm minimum trace width and 6 mm minimum spacing. I've heard of people using OSH Park and similar lower-end prototyping services to manufacture one-off PCBs for fine-pitch BGAs, but you'll be failing DRC by a massive margin, so expect terrible yield on the PCBs, assuming any of them work at all. Unfortunately I think DRC will be similarly challenging for most SoM connectors since their pin spacing has a similar pitch to BGAs, so you'll probably need an off-the-shelf break-out board to work around that. Honestly, at some point you should consider whether a vanilla dev board with low-speed GPIO headers could meet your requirements.
- leggomylibro 9y ago
  Those OSHPark rules are 6mil, not mm - that's a little over 0.15mm. But it's still not really suitable for BGP modules. You can probably do 60-ball RAM modules, but a medium-sized processor seems like it would be off the table. I think that dirtyPCBs does 6-layer boards, but they're comparatively pricey for small runs or prototypes.
  - psykotic 9y ago
    Thanks for the correction; I thought 6 mm sounded way too high. Gotta love American measurement units! There are Internet accessible Chinese PCB manufacturers that will do short runs for designs of almost any complexity, but they aren't really targeting hobbyists, though that seems to be changing.
    - leggomylibro 9y ago
      Yeah, mils are a really strange measurement unit. I'm not sure who thought that 1/1000" would be a good standard.
      - semi-extrinsic 9y ago
        I think it harks back to older manufacturing processes, via plastics (where mils are used) back to metalworking. Machinists will usually talk about small distances in "thou", as in thousandths of an inch. Always cracks me up when AvE mentally converts 2.5/64" or some crazy shit into thou while thinking out loud, and then goes "metric fanboys be like whaaat?"
leggomylibro 9y ago
Huh, I hadn't heard of that sort of thing, besides the various dev boards offered by the microprocessor developers. Thanks!

robert_foss 9y ago

I'm hardly an electronics designer (although I do it for fun), so I don't have much of an opinion. However, I don't think there are any SOCs with Adreno or Vivante GPUs that are also hand solderable. A quick Octopart search[1] turned up nothing. About iMX23, a quick look seems to suggest that it has no 2D/3D capable IP on the SOC. So it likely just has a display controller of some sort. Unfortunately I don't know what that display controller is. It may be encompassed by the imx driver depending on that the hardware actually is. [1] https://octopart.com/search?q=&start=0&category_ids=4267&specs2.2.values=LQFP&specs2.2.values=TQFP&specs2.2.values=QFN&specs2.2.values=QFN%20EP&specs2.2.values=QFP&specs2.2.values=VQFN https://octopart.com/search?q=&start=0&category_ids=4267&spe...

jdboyd 9y ago

The AllWinner A13 (Cortex A8) is available in a LQFP176 package. That includes a MALI400 GPU. That is still fairly old, but more up to date than ARM926.

deleted 9y ago
[deleted]