SPI initiation sequence about sdspi

[ZipCPU]

@watmes ,
Thank you for posting this issue. Do you have a reference at all for a document or specification stating this fact? I'm not finding it anywhere in the SD Card specification. Worse, in general with SPI, the clock can typically be anything if CSn is high (inactive). This would break SPI compatibility with other devices, and in particular compatibility on shared SPI buses, if true.
Dan

[ZipCPU]

Nevermind, I think I found in it section 6.4.1.1, Power Up Time of Card", of the SD Specifications Part 1 Physical Layer Simplified Specification. My copy is marked as version 4.1 and dated 22 January, 2013.

:/ Fixing this will break some other things, but I suppose it needs to be done.

[ZipCPU]

Should be fixed now. I also made the SPI bus arbitration optional (only one of my designs ever used it), and the core now supports SPI clocks as fast as half the bus rate.

Dan