Add reclock functionality for SPI #98
Conversation
src/spi.rs
Outdated
| @@ -114,6 +114,20 @@ pub struct Spi<SPI, PINS> { | |||
| pins: PINS, | |||
| } | |||
|
|
|||
| fn compute_clock_variant(clocks: Hertz, freq: Hertz) -> u8 { | |||
There was a problem hiding this comment.
This could use the type-safe alternative
There was a problem hiding this comment.
Also rename to
| fn compute_clock_variant(clocks: Hertz, freq: Hertz) -> u8 { | |
| fn compute_baud_rate(clocks: Hertz, freq: Hertz) -> u8 { |
| pub fn reclock<F>(&mut self, freq: F, clocks: Clocks) | ||
| where F: Into<Hertz> | ||
| { | ||
| self.spi.cr1.modify(|_, w| w.spe().disabled()); |
There was a problem hiding this comment.
Are there any side effects changing the frequency, or is it sufficient to disable and enable it right after it? Any delay needed?
There was a problem hiding this comment.
Unfortunately I didn't find any documentation about this.
All I can say is that I tested this with an SD card using the embedded-sdmmc library. I initialize the card at 400KHz, then I switch to 16Mhz and data is red without a problem. I'm reading mp3s from the SD-card and playing them (after decoding) at the same time. Would there be a problem I think I'd notice it. If I leave the card at 400Khz the playing doesn't go well. I tried this also by initializing the card directly at 8 Mhz, and I would get random things and strange crashes in the sdmmc library. I also believe this depends on the device at the other end. With SD cards this works, with other devices it might not.
| @@ -200,6 +204,17 @@ macro_rules! hal { | |||
| pub fn free(self) -> ($SPIX, (SCK, MISO, MOSI)) { | |||
| (self.spi, self.pins) | |||
| } | |||
|
|
|||
| pub fn reclock<F>(&mut self, freq: F, clocks: Clocks) | |||
|
@Sh3Rm4n Thank you for your review. I believe I addressed all your comments. |
|
@Sh3Rm4n thank you for your review. I don't have the rights to merge the PR. Could you do it for me? |
CHANGELOG.md
Outdated
| @@ -15,6 +15,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/). | |||
| - Support for safe one-shot DMA transfers ([#86](https://github.com/stm32-rs/stm32f3xx-hal/pull/86)) | |||
| - DMA support for serial reception and transmission ([#86](https://github.com/stm32-rs/stm32f3xx-hal/pull/86)) | |||
| - ADC support for `stm32f303` devices ([#47](https://github.com/stm32-rs/stm32f3xx-hal/pull/47)) | |||
| - SPI support for reclock after initialization ([#98](https://github.com/stm32-rs/stm32f3xx-hal/pull/98)) | |||
There was a problem hiding this comment.
This is the wrong place, as 0.5.0 is already released. You'd have to move it under Unreleased :)
Some devices (eg SD cards) require the initialization to be done a at a lower frequency and allow the frequency to be later increased. Thus a re-clock functionality has been added. The tm4c123x-hal also does this.