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address issues from testing

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Mirabellensaft 2023-03-13 13:29:44 +01:00
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19
embedded-workshop-book/src/uarte-implementation.md
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@ -8,7 +8,7 @@ The UART protocol requires four pins, they are usually labelled:
* TXD * TXD
* CTS * CTS
* RTS * RTS
Check the User Guide in section 7.2 to find to find out which pins are reserved for these and what their configuration needs to be. Check the User Guide in section 7.2 to find to find out which pins are reserved for these and what their configuration needs to be.
### Step 2: Explore the `nrf-hal` to find out what needs to be done. ### Step 2: Explore the `nrf-hal` to find out what needs to be done.
@ -24,7 +24,7 @@ A quick search of the document reveals where to find all of them:
* `Parity` and `Baudrate`: Re-export on line 34 * `Parity` and `Baudrate`: Re-export on line 34
Add the following lines as import: Add the following lines as import:
```rust ```
use hal::pac::uarte0::{ use hal::pac::uarte0::{
baudrate::BAUDRATE_A as Baudrate, config::PARITY_A as Parity}; baudrate::BAUDRATE_A as Baudrate, config::PARITY_A as Parity};
use hal::uarte; use hal::uarte;
@ -36,8 +36,11 @@ The struct has one field labelled `inner`, it contains the `UARTE1` instance: `h
<!-- Solution Code Snippet --> <!-- Solution Code Snippet -->
### Step 4: Bring up the peripheral in the `fn init()` ### Step 4: Bring up the peripheral in the `fn init()`
Take a closer look at the definition of the `uarte::Pins` struct. Import the types of the pin configuration that you don't have yet. Note, that the third and fourth pin are each wrapped in an `Option`. Take a closer look at the definition of the `uarte::Pins` struct in the `nrf-hal`. Compare the pin type configurations with the ones you have already imported in `lib.rs`. Add the ones you're missing.
Create an instance of this struct in `fn init()` with the appropriate pins and configurations. Set the output pin's level to `Level::High`. Create an instance of this struct in `fn init()` with the appropriate pins and configurations. Set the output pin's level to `Level::High`.
Note, that the third and fourth pin are each wrapped in an `Option`.
Create an interface to the UARTE1 instance with `uarte::Uarte::new(...)` that you bind to a variable. This instantiating method takes four arguments: Create an interface to the UARTE1 instance with `uarte::Uarte::new(...)` that you bind to a variable. This instantiating method takes four arguments:
* The `UARTE1` instance can be found in the `periph` variable. * The `UARTE1` instance can be found in the `periph` variable.
@ -54,7 +57,9 @@ add the field to the instance of the `Board` struct in `fn init()`.
<!-- Solution Code Snippet --> <!-- Solution Code Snippet -->
### Step 6: Implementing the `fmt::Write` trait ### Step 6: Implementing the `fmt::Write` trait
We can't just write to the Uarte instance. A simple write would write from flash memory. This does not work because of EasyDMA. We have to write a function that implements the `fmt::Write` trait. This trait guarantees that the buffer is fully and successfully written on a stack allocated buffer, before it returns. We can't just write to the `Uarte` instance. A simple write would write from flash memory. This does not work because of EasyDMA. We have to write a function that implements the `fmt::Write` trait. This trait guarantees that the buffer is fully and successfully written on a stack allocated buffer, before it returns.
Add `use::core::fmt;` to your imports.
Create a public method `write_str`. It takes a mutable reference to self and a `&str` as argument. It returns an `fmt::Result` Create a public method `write_str`. It takes a mutable reference to self and a `&str` as argument. It returns an `fmt::Result`
@ -76,7 +81,7 @@ return `Ok(())`
Use the following command to find the address of the nRF52840-DK on your computer. Use the following command to find the address of the nRF52840-DK on your computer.
``` ```
ls /dev/tty* ls /dev/tty.usbmodem*
``` ```
Run the following command to run `screen` with the nRF52840-DK with 115200 baud. Run the following command to run `screen` with the nRF52840-DK with 115200 baud.
@ -94,4 +99,6 @@ Use the following command.
cargo run --bin uarte_print cargo run --bin uarte_print
``` ```
On your terminal window where `screen` runs, "Hello, World" should appear. On your terminal window where `screen` runs, "Hello, World" should appear.
You need to terminate `screen` manually.