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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
* CTS
* 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.
### 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
Add the following lines as import:
```rust
```
use hal::pac::uarte0::{
baudrate::BAUDRATE_A as Baudrate, config::PARITY_A as Parity};
use hal::uarte;
@ -36,8 +36,11 @@ The struct has one field labelled `inner`, it contains the `UARTE1` instance: `h
<!-- Solution Code Snippet -->
### 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`.
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:
* 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 -->
### 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`
@ -76,7 +81,7 @@ return `Ok(())`
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.
@ -94,4 +99,6 @@ Use the following command.
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.