mirror of
https://github.com/hsoft/collapseos.git
synced 2024-11-01 18:30:55 +11:00
7001446212
Recipes contain bits and pieces of hardware-related knowledge, but these bits feel sparse. I've been wanting to consolidate hardware- related documentation for a while, but always fell at odds with the recipes organisation. We don't have recipes anymore, just a /doc/hw section that contains hardware-related documentation which often translate to precise instructions to run Collapse OS on a specific machine. With this new organisation, I hope to end up with a better, more solid documentation.
30 lines
1.2 KiB
Plaintext
30 lines
1.2 KiB
Plaintext
# Accessing SD cards
|
|
|
|
SD cards support the SPI protocol. If you have a SPI relay
|
|
(doc/hw/spi.txt) and a driver for it that implement the SPI
|
|
protocol (doc/protocol.txt), you're a few steps away from
|
|
accessing SD cards!
|
|
|
|
What you need to do is to add the SDC subsystem to your Collapse
|
|
OS binary. First, define SDC_DEVID to a mask selecting the
|
|
proper device on your SPI relay (this is what is sent to
|
|
"(spie)"). For example, a SDC_DEVID or 1, 2, 4, or 8 would
|
|
select SPI device 1, 2, 3 or 4.
|
|
|
|
The subsystem is loaded with "423 436 LOADR".
|
|
|
|
Initialization of the SDC system is done in multiple steps.
|
|
First, the BLK system needs to be initialized with "BLK$". Then
|
|
you can plug SDC@ and SDC! into BLK with "' SDC@ BLK@* !" and
|
|
"' SDC! BLK! !". That only needs to be done once per boot.
|
|
|
|
Then, the SD card that was inserted needs to be initialized. You
|
|
can do it with "SDC$". If you have no error, it means that the
|
|
system can spek to your card, that sync is fine, etc. You can
|
|
read/write right now. SDC$ needs to run every time a new card
|
|
is inserted.
|
|
|
|
Collapse OS' SDC drivers are designed to read from the very
|
|
first 512 sector of the card, mapping them to blocks
|
|
sequentially, 2 sectors per block.
|