uSD Breakout
#28
Tonight I got my parts BOM ordered;  btw the 5x2 1.27 pitch J3 header may be purchased from Mouser.  

I have verified the rest of the schematic using a continuity tester;  All gpio breakouts from the mcp23s17 have been verified on header connections; the four SPI pins jumpered at J3 from the SD pins to the mcp23s17 SPI control lines are correct; the mcp hardware address lines are correctly tied to ground, and the two interrupt lines are brake-out but not connected -- will require careful soldering. 

The power supply pin is jumpered to the padi stamp;  all padi stamp breakouts are available on header connections; decoupling caps have been verified; not sure yet about the center 5mm x 5mm ground pad; 

VDD has been verified as 3v3 from the SD card slot;  VDD is hard-wired to the mcp23s17 and jumpered to the padi stamp; ground pins headers (2) have been provided; all grounds have been hard-wired across the board;

The J3 headers can be provided, or the jumpers could also alternatively be soldered in place as tiny zero ohm loops.  Alternatively the jumper headers may be cabled off to another card !  In such a configuration the hardware address lines would not be tied to ground (totally) but would have one pin biased high;  the control register could then be used to select the second card and the expansion port would now have 32bits !  In order to write to the chip the control register bits A0 A1 A2 must match the hardware bits A0 A1 A2 which must be externally biased;  the uSD has been designed for single card operation with all hardware lines soldered LOW;  on my cards I will choose to select one unique bit in the control register for each card for external bias HIGH.  

The surface soldering is going to be done with an airgun soldering station (low air about 370) and using chipquik soldering paste -- has fine tip applicator.

Note:  take care with the mcp ordering;  mcp23017 is I2C controlled! <=== we don't want this one

Note:  take care with the mcp ordering;  mcp23s17 is SPI controlled serial I|O  <=== THIS IS THE ONE

the datasheet is the same for both;  you need to pull out what you want for SPI operation  )
marcushh777    Cool

please join us for a chat @  irc.pine64.xyz:6667   or ssl  irc.pine64.xyz:6697

( I regret that I am not able to respond to personal messages;  let's meet on irc! )
  Reply


Messages In This Thread
uSD Breakout - by machinehum - 08-29-2017, 06:59 PM
RE: uSD Breakout - by MarkHaysHarris777 - 08-29-2017, 07:01 PM
RE: uSD Breakout - by machinehum - 08-29-2017, 08:09 PM
RE: uSD Breakout - by machinehum - 08-31-2017, 11:14 PM
RE: uSD Breakout - by machinehum - 09-05-2017, 08:04 PM
RE: uSD Breakout - by MarkHaysHarris777 - 09-05-2017, 09:16 PM
RE: uSD Breakout - by martinayotte - 09-06-2017, 07:59 AM
RE: uSD Breakout - by MarkHaysHarris777 - 09-06-2017, 08:52 AM
RE: uSD Breakout - by machinehum - 09-06-2017, 10:25 AM
RE: uSD Breakout - by dkryder - 09-06-2017, 04:56 PM
RE: uSD Breakout - by machinehum - 09-06-2017, 10:43 PM
RE: uSD Breakout - by machinehum - 09-08-2017, 07:45 PM
RE: uSD Breakout - by dkryder - 09-09-2017, 05:43 AM
RE: uSD Breakout - by martinayotte - 09-09-2017, 07:31 AM
RE: uSD Breakout - by MarkHaysHarris777 - 09-09-2017, 09:40 AM
RE: uSD Breakout - by machinehum - 09-09-2017, 06:45 PM
RE: uSD Breakout - by martinayotte - 09-10-2017, 07:38 AM
RE: uSD Breakout - by machinehum - 09-20-2017, 04:59 PM
RE: uSD Breakout - by dkryder - 09-21-2017, 01:37 AM
RE: uSD Breakout - by machinehum - 09-21-2017, 10:59 AM
RE: uSD Breakout - by martinayotte - 09-21-2017, 11:59 AM
RE: uSD Breakout - by dkryder - 09-24-2017, 12:51 AM
RE: uSD Breakout - by machinehum - 09-27-2017, 11:19 AM
RE: uSD Breakout - by machinehum - 09-27-2017, 05:58 PM
RE: uSD Breakout - by MarkHaysHarris777 - 10-06-2017, 09:29 PM
RE: uSD Breakout - by MarkHaysHarris777 - 10-07-2017, 12:13 AM
RE: uSD Breakout - by machinehum - 10-07-2017, 01:13 PM
RE: uSD Breakout - by MarkHaysHarris777 - 10-11-2017, 02:13 AM
RE: uSD Breakout - by machinehum - 10-11-2017, 10:49 AM
RE: uSD Breakout - by MarkHaysHarris777 - 10-13-2017, 06:19 AM
RE: uSD Breakout - by machinehum - 10-20-2017, 11:14 AM
RE: uSD Breakout - by tllim - 10-25-2017, 11:49 AM
RE: uSD Breakout - by dkryder - 11-10-2017, 07:47 PM

Forum Jump:


Users browsing this thread: 1 Guest(s)