Actually you are right in this regard, those some cards are most probably MMCs using open-collector (up to 400 KHx) for init phase before getting in SPI mode, while they are NOT in SPI mode. Also, they can ignore CS/SS and remain active. Besides, there are MMCs which are not supporting SPI mode, at all. I have some.
This is Arduino style (from where the article is inspired) and it doesn't make the author(s) less wrong:
This is Arduino style (from where the article is inspired) and it doesn't make the author(s) less wrong:
Well, maybe a proper initialization before starting them (and others) on a shared SPI bus would help more ...If you’re using an SD-MMC card, or if all else fails, or if you’re just somehow superstitious, you can try adding pull-up resistors to various lines to stabilize them during power-up or for some other magical reasons.
Statistics: Posted by gmx — Wed Sep 11, 2024 2:24 am