SPI bus for SD card and other slaves

RE: SPI bus for SD card and other slaves

Jørgen Holmefjord — Fri, 27 Nov 2020 09:39:58 GMT

Some SD cards requires pullup on the MISO line, but this is related to the SD card, and not the nRF SoC. You should pullup the line on the SD card side of the level converter for the pullup to have any effect.

RE: SPI bus for SD card and other slaves

bardia3000 — Fri, 27 Nov 2020 09:19:42 GMT

I decided to redesign my PCB, But I have another problem, should I pull up the MISO pin of SD card? As I said before I use TXB0108 as level translator (my micro uses 1v8 but my SD card uses 3v3), Which side of TXB0108 should be pulled up (near micro or near sdcard)?

RE: SPI bus for SD card and other slaves

Jørgen Holmefjord — Wed, 25 Nov 2020 12:49:20 GMT

If you fully uninitialize the SPI driver and SD-card library/FatFS between each time it is used, this should be possible, however you need to do this for both, as the SD-card library uses the same SPI driver and instance as you use in your application. If you keep one running, it will be left in a wrong state in one of the places being used.

Can you post the full code for how you have implemented this?

RE: SPI bus for SD card and other slaves

bardia3000 — Tue, 24 Nov 2020 13:59:01 GMT

Unfortunately I designed and got the PCB, for next time I will change it, But for now is this possible?

RE: SPI bus for SD card and other slaves

bardia3000 — Mon, 23 Nov 2020 19:27:27 GMT

Thanks for you reply, I tried another idea, I uninitialized SPI just before start of the SD card code using "nrf_drv_spi_uninit(&spi);" and again reinitialized it at the end of using SD card, but it stays at "diskio_blkdev.c" line 120: "m_drives[drv].config.wait_func();", I can't find what is wrong with this.

RE: SPI bus for SD card and other slaves

Jørgen Holmefjord — Mon, 23 Nov 2020 10:30:09 GMT

Hi,

See my answer in this thread. Do you need to have the SD-card and the other slaves on the same SPI bus? It would be much simpler to run the SD-card on a separate SPI instance, with its own GPIOs. The nRF52832 has 3 available SPI(M) instances.

Best regards,
Jørgen