Shared QSPI driver help

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seulater
Posts: 445
Joined: Fri Apr 25, 2008 5:26 am

Shared QSPI driver help

Post by seulater »

I need to use the SD card and communicate with another SPI device.
I believe the SD card uses the shared QSPI driver. NB, can you offer a quick example of how one would be able to use the SD card and then release it so i can then communicate with my device, then release that and re-enable the SD card driver.
rnixon
Posts: 833
Joined: Thu Apr 24, 2008 3:59 pm

Re: Shared QSPI driver help

Post by rnixon »

Sharing can be very difficult. In the flash card docs it says the sd card must have exclusive access. I have seen threads here on sharing, but I think its better to be exclusive, especially for throughput issues. I think the new modules have multiple spi, so you can use different ones and not share a single channel.
greengene
Posts: 164
Joined: Wed May 14, 2008 11:20 am
Location: Lakeside, CA

Re: Shared QSPI driver help

Post by greengene »

There is an example that should be of help in the _new_ 2.6.0 release from 10/2.

# RELEASE 2.6.0 (September 2012)
## New in this version
* Examples
* Added EFFS/WIFI shared QSPI example
seulater
Posts: 445
Joined: Fri Apr 25, 2008 5:26 am

Re: Shared QSPI driver help

Post by seulater »

I did look at that example before i posted. For me its not clear on how the sharing is done.
I.E. is it done all behind the scenes as far as when i want to use the SD card vs. my device.
or do i have to make a call before used each.

I am looking for something simpler to be explained.
greengene
Posts: 164
Joined: Wed May 14, 2008 11:20 am
Location: Lakeside, CA

Re: Shared QSPI driver help

Post by greengene »

oh, ok. i now actually looked at their example :? i think their sharing mechanism is tied closely to those 2 devices. so i'll go along with rnixon for you to check some of the other spi sharing threads. we do it on our devices - i posted some about that before too.
seulater
Posts: 445
Joined: Fri Apr 25, 2008 5:26 am

Re: Shared QSPI driver help

Post by seulater »

The other examples are for the regular SPI and not QSPI. This is the latest driver for the latest release. So i was looking for them to explain how to use it as a shared peripheral. Or, maybe i am getting to hung up on the word "shared" to mean that i can share the QSPI with the SD.
They may mean shared to pertain that you can use SD and Wi-Fi together, but like you said they are tied closely to each other.
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