SD cards, interrupts, and DMA Mar 29, 2017

This week is another potpourri of code for the STM32F103, the purpose of which will become clear next week… suspense!

SD cards and µSD cards have a ridiculous amount of storage in a very small package. All solid-state, no moving parts, very quick to read and write, and easily accessed from a µC through just 4 I/O pins.

Next on the menu: an exploration into how hardware interrupts and Mecrisp’s multi-tasker can be combined, as a convenient and robust way to deal with interrupts.

Lastly, I’ll set up SPI in slave mode, using DMA to support bi-directional high speed data transfers that don’t burn CPU cycles:

• SD cards with FAT files - Wed
• Interrupts, tamed at last - Thu
• Tying SPI and DMA together - Fri

And as you might have guessed by now: it’s all being developed interactively in Forth.