Pinebook SDIO gpio control using SD card slot blog post

[machinehum]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

[MarkHaysHarris777]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

I'm definitely interested in providing input !  

I think .8mm  would be pressing it;  but, really,  the best way to spec the end of the board is that it should look and be precisely identical (exactly) with a micro SD card !  --not thicker,  not thinner;

Also, it needs to be able to activate the spring latch correctly of a push-push slot like the one in the Pinebook.

The Sparkfun board works but is sloppy in both regards to the above two requirements.  The other brand does not work at all because its too thick to enter the slot... it won't even enter the slot of a carrier outside the Pinebook !

[machinehum]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

I'm definitely interested in providing input !  

I think .8mm  would be pressing it;  but, really,  the best way to spec the end of the board is that it should look and be precisely identical (exactly) with a micro SD card !  --not thicker,  not thinner;

Also, it needs to be able to activate the spring latch correctly of a push-push slot like the one in the Pinebook.

The Sparkfun board works but is sloppy in both regards to the above two requirements.  The other brand does not work at all because its too thick to enter the slot... it won't even enter the slot of a carrier outside the Pinebook !

The wikipedia says they're 1mm thick? So I'm not sure why the 1mm thick PCB didn't work at all. It's possible they didn't pull the solder mask back far enough, so the FR4 is 1mm + solder mask > 1mm - is it close? or completely out to lunch?

It's difficult to get PCB's to an "exact" thickness, typically you just get whatever your CM offer.

Spring latch should be easy to do.

Do you have any other input? or is  a pure breakout good enough? I think it would be cool to get an STM32 or ATMEGA onboard as well, then you could piggyback of their peripherals and communicate over SPI. I think the key would be to keep it really small, so you can bring it around.

[MarkHaysHarris777]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

I'm definitely interested in providing input !  

I think .8mm  would be pressing it;  but, really,  the best way to spec the end of the board is that it should look and be precisely identical (exactly) with a micro SD card !  --not thicker,  not thinner;

Also, it needs to be able to activate the spring latch correctly of a push-push slot like the one in the Pinebook.

The Sparkfun board works but is sloppy in both regards to the above two requirements.  The other brand does not work at all because its too thick to enter the slot... it won't even enter the slot of a carrier outside the Pinebook !

The wikipedia says they're 1mm thick? So I'm not sure why the 1mm thick PCB didn't work at all. It's possible they didn't pull the solder mask back far enough, so the FR4 is 1mm + solder mask > 1mm - is it close? or completely out to lunch?

It's difficult to get PCB's to an "exact" thickness, typically you just get whatever your CM offer.

Spring latch should be easy to do.

Do you have any other input? or is  a pure breakout good enough? I think it would be cool to get an STM32 or ATMEGA onboard as well, then you could piggyback of their peripherals and communicate over SPI. I think the key would be to keep it really small, so you can bring it around.

Yes:  I would put three components on the breakout so that they can be jumper'd:

1)  RTL8710     (padi stamp)
2)  74HC165     parallel in -- serial out shift register [tiny surface mount chips]
3)  74HC595     serial in -- parallel out shift register [tiny surface mount chips]

again the breakout should allow jumpering of all components which would make this board the ultimate gpio expander for the SDcard slot SDIO.  Input lines, output lines, could even be jumpered for matrix scan (keyboard input 8x8) and of course the wifi module with MCU !

This is the board I've been thinking of;

[machinehum]

This is a really cool idea, thanks for sharing.

The last post people are talking about issues with the current solution - I want to start a little opensource project designing a breakout for this, I can label all the pins and incorporate whatever else would be useful, LEDs, sensors, headers, etc...

Seeed can manufacture PCBs that are 0.6mm & 0.8mm, I believe a post above said they must not be thicker than 0.75mm, but the height of a uSD card is ~1mm - would the 0.6mm or 0.8mm be best?


I can also send out some free board for people. They'll be dirt cheep.

Let me know if anyone is interested in helping out (feedback, suggestions, etc...) we can set up a time on the IRC

~wlkr

I'm definitely interested in providing input !  

I think .8mm  would be pressing it;  but, really,  the best way to spec the end of the board is that it should look and be precisely identical (exactly) with a micro SD card !  --not thicker,  not thinner;

Also, it needs to be able to activate the spring latch correctly of a push-push slot like the one in the Pinebook.

The Sparkfun board works but is sloppy in both regards to the above two requirements.  The other brand does not work at all because its too thick to enter the slot... it won't even enter the slot of a carrier outside the Pinebook !

The wikipedia says they're 1mm thick? So I'm not sure why the 1mm thick PCB didn't work at all. It's possible they didn't pull the solder mask back far enough, so the FR4 is 1mm + solder mask > 1mm - is it close? or completely out to lunch?

It's difficult to get PCB's to an "exact" thickness, typically you just get whatever your CM offer.

Spring latch should be easy to do.

Do you have any other input? or is  a pure breakout good enough? I think it would be cool to get an STM32 or ATMEGA onboard as well, then you could piggyback of their peripherals and communicate over SPI. I think the key would be to keep it really small, so you can bring it around.

Yes:  I would put three components on the breakout so that they can be jumper'd:

1)  RTL8710     (padi stamp)
2)  74HC165     parallel in -- serial out shift register     [tiny surface mount chips]
3)  74HC595     serial in -- parallel out shift register     [tiny surface mount chips]

again the breakout should allow jumpering of all components which would make this board the ultimate gpio expander for the SDcard slot SDIO.  Input lines, output lines, could even be jumpered for matrix scan (keyboard input 8x8) and of course the wifi module with MCU !

This is the board I've been thinking of;

o7


I'll get going on this next week and keep everyone posted. I've been using hackaday.io for updates and github for VCS.

~wlkr

[MarkHaysHarris777]

Please see this important link:

   


I am now in the process of testing machinehum's uSD Breakout;  see above link for details.

This little board provides access to the six gpio(s) of the SD card slot ( is a great sniffer by itself ) but with the MCP23S17 chip will provide 16 parallel input|output gpio lines serial controlled ( SPI ) as well a padi stamp for extras !