topic Re: microSD/SPI issue initializing card in Kinetis Microcontrollers

microSD/SPI issue initializing card

richardsabourin — Fri, 28 Mar 2014 14:23:26 GMT

Hi all,

I have experience with Kinetis and SPI, but this is my first time bringing up an SD card interface. Starting with a TWR-K20D72M tower board, I have wired a microSD card (proto board from MicroElectronika) to SPI0 through the TWRPI connector J8.

The init sequence is well known, and I'm 95% sure the signals are getting to the card, but the MISO line seems to not be driven properly by the card. It's just some sort of reflection. A couple of scope shots of CMD0 are attached. The clock speed is ~ 180 KHz.

I've seen a couple old postings of this issue in other forums, but no solution. Anybody seen this before, and know what it means? Any advice appreciated!

Re: microSD/SPI issue initializing card

richardsabourin — Fri, 28 Mar 2014 18:54:26 GMT

SOLVED: Bad solder joints.

Re: microSD/SPI issue initializing card

mjbcswitzerland — Fri, 28 Mar 2014 20:29:25 GMT

Richard

I am a little late but I was wondering whether the power supply was missing at the SD card.

Also I was going to send a reference application that uses the same SD card interface on the TWR board as reference to check that it was HW.

In case you still need something I have the following:

http://www.uTasker.com/freescale/TWR_K20D72M_USB-MSD-SD_card_SPI0.srec

which can be loaded to the board using the CW flash utility.

It performs USB-MSD when a PC is connected to the application USB port so the SD card appears as an external hard-drive. If the serial card is connected in the tower kit at the same time the UART can be used to access a DOS-like interface (115k - in menu 8 o fthe command line interface) where a local FAT works with the SD card and also allows viewing SD card sectors and doing analysis on files entries for SFN and LFNs, etc.

Regards

Mark

The FAT used is documented here: http://www.utasker.com/docs/uTasker/uTasker_utFAT.PDF

The USB stack used is documented here: http://www.utasker.com/docs/uTasker/USB_User_Guide.PDF

Re: microSD/SPI issue initializing card

richardsabourin — Mon, 31 Mar 2014 15:26:06 GMT

Mark,

Thanks for your response, I will check out that application.