ChipworkX Hardware Version 1.2 SD known issue and design solution

NETMF & Gadgeteer
1

In some rare cases some SD cards do not mount successfully with ChipworkX Development system.

Solution:
connect 10K pull-up resistor from pin PA0 to VCC(3.3v).

This problem is solved in ChipworkX Development System hardware version 1.5 and up.

2

Hi Gus

Is there any document where we can check differences between vr 1.2 and 1.5?.. functions improved, etc?

3

Both schematics are here http://www.ghielectronics.com/downloads/ChipworkX/
There is no document with differences.

4

Hello Gus

Values adviced for R5 and R6?. What does it mean DNP? R4=0 Ohms means a short circuit, put a jumper replacing R4?

Thanks for your support

5

0ohm = short circuit
DNP= do not populate or do not place.

6

That means R5 and R6 should be replaced by short circuit too…right?

7

If a resistor is 0ohm then you can remove it and just run the trace directly.

8

Sorry but that was not my question. R5 and R6 DNP…means these R should be replaced by short circuits?
Thanks

9

No it means do not add this singal

10

Gus
Please let me understand something:

  1. That means PA4 and PA5 are not needed for MMC operation.
  2. I have a problem when I put a 10K resistor between pin 7 of MMC and Vcc, touch stops to work and MMC neither is recognized. As PA0, PA1 and PA2 are common signals shared by MMC and touch. I wonder if any kind of signals coupling is needed in order these work properly.

Your comments and suggestions will be very appreciated

11

How different is what you have from our schematics?

The dnp resistors were for signals we thought about using but we never did so you can take out that signal completely from your design.

12

As it has not been possible to do SD/MMC memory works in our development. I have a question: What do we have to do with WP and CD signals from the SD/MMC socket?..Thanks

13

Those are up to you to connect to any IO. They are not needed to use SD cards.

14

SD/MMC Socket has something to do or any socket should work?..it’s the only difference between our development and GHI SDK. :frowning:

15

Are you sure you have counted the pins right?

On SD, the pins are ordered 912345678 http://1.bp.blogspot.com/_AbyOW0v25Ro/SkHrZADJatI/AAAAAAAAABg/-g_F1Ui-XuI/s320/SD_pinout.JPG

16

Yes, we are exactly as the beginning. as soon as we put the pull up resistor between PA0 and Vcc, touch stops to work and SD memory is neither recognized. I don’t know what else to do… :’(…it seems there is a conflict between protocols signals or IRQs…but we haven’t been able to find the problem…thanks again for any idea or suggestion.

17

I am not finding a logical explanation. How would 10K resistor effect MISO pin? Pull up to 3.3V not 5V of course.

ChipworkX is not 5V tolerant. Nothing should be 5V

18

Sorry Vcc means 3.3 Vdc. We are not using 5 volts with Chipworkx module.

19

Finally it’s working!..but still have a problem when pull up resistor is connected. The 1st time, when system is power up, it does not recognize the SD card but then it starts to work with no problem (the same behaviour as Chipworkx Hardware vr 1.2 with no pull up resistor). If somebody has had the same problem, maybe we can share our experiences in order to check what is going on or what the mistake was. Thanks for your support

20

What is the maximum capacity of SD card memories supported by ChipworkX?.. I have a 4 gigabytes card and some has problems being detected. 2 gigabytes works better.