alex/esp-idf
1
0
Fork 0
mirror of https://github.com/espressif/esp-idf.git synced 2025-11-26 12:50:30 +00:00
Code Issues Packages Projects Releases Wiki Activity

examples: fix echo example crash when UART interrupt handler placed in IRAM

Browse Source
This commit is contained in:
Alex Lisitsyn
2020-08-06 19:32:11 +08:00
committed by Michael (XIAO Xufeng)
parent bd920d22b0
commit df9ca688d7
3 changed files with 98 additions and 31 deletions
Download Patch File Download Diff File Expand all files Collapse all files

45
examples/peripherals/uart/uart_echo/README.md
View File

@@ -2,25 +2,30 @@
(See the README.md file in the upper level 'examples' directory for more information about examples.)
This example demonstrates how to utilize UART interfaces of ESP32 by echoing back to the sender any data received on
UART1.
This example demonstrates how to utilize UART interfaces by echoing back to the sender any data received on
configured UART.
## How to use example
### Hardware Required
The example can be run on any ESP32 development board connected to a PC with a single USB cable for flashing and
The example can be run on any ESP32 or ESP32-S2 based development board connected to a PC with a single USB cable for flashing and
monitoring. The external interface should have 3.3V outputs. You may use e.g. 3.3V compatible USB-to-Serial dongle.
### Setup the Hardware
Connect the external serial interface to the ESP32 board as follows.
| ESP32 Interface | #define | ESP32 Pin | External UART Pin |
| --- | --- | --- | --- |
| Transmit Data (TxD) | ECHO_TEST_TXD | GPIO4 | RxD |
| Receive Data (RxD) | ECHO_TEST_RXD | GPIO5 | TxD |
| Ground | n/a | GND | GND |
Connect the external serial interface to the ESP32(S2) board as follows.
```
---------------------------------------------------------------------------------------
| Target chip Interface | #define | Default ESP32(S2) Pin| External UART Pin |
| ----------------------|------------------|----------------------|--------------------
| Transmit Data (TxD) | EXAMPLE_UART_TXD | GPIO4 | RxD |
| Receive Data (RxD) | EXAMPLE_UART_RXD | GPIO5 | TxD |
| Ground | n/a | GND | GND |
---------------------------------------------------------------------------------------
```
Note: The GPIO22 - GPIO25 can not be used with ESP32-S2 chip because they are reserved for internal use. Please refer to UART documentation for selected target.
Optionally, you can set-up and use a serial interface that has RTS and CTS signals in order to verify that the
hardware control flow works. Connect the extra signals according to the following table, configure both extra pins in
@@ -28,13 +33,20 @@ the example code by replacing existing `UART_PIN_NO_CHANGE` macros with the appr
UART1 driver to use the hardware flow control by setting `.flow_ctrl = UART_HW_FLOWCTRL_CTS_RTS` and adding
`.rx_flow_ctrl_thresh = 122`.
| ESP32 Interface | #define | ESP32 Pin | External UART Pin |
| --- | --- | --- | --- |
| Request to Send (RTS) | ECHO_TEST_RTS | GPIO18 | CTS |
| Clear to Send (CTS) | ECHO_TEST_CTS | GPIO19 | RTS |
```
--------------------------------------------------------------------------------------
| Target chip Interface | #define | Default ESP32(S2) Pin| External UART Pin |
| ----------------------|-----------------|----------------------|--------------------
| Transmit Data (TxD) | ECHO_TEST_RTS | GPIO18 | CTS |
| Receive Data (RxD) | ECHO_TEST_CTS | GPIO19 | RTS |
| Ground | n/a | GND | GND |
--------------------------------------------------------------------------------------
```
### Configure the project
Use the command below to configure project using Kconfig menu as showed in the table above.
The default Kconfig values can be changed such as: EXAMPLE_TASK_STACK_SIZE, EXAMPLE_UART_BAUD_RATE, EXAMPLE_UART_PORT_NUM (Refer to Kconfig file).
```
idf.py menuconfig
```
@@ -54,10 +66,9 @@ See the Getting Started Guide for full steps to configure and use ESP-IDF to bui
## Example Output
Type some characters in the terminal connected to the external serial interface. As result you should see echo in the
terminal which is used for flashing and monitoring. You can verify if the echo indeed comes from ESP32 by
terminal which is used for flashing and monitoring. You can verify if the echo indeed comes from ESP32(S2) board by
disconnecting either `TxD` or `RxD` pin: no characters will appear when typing.
## Troubleshooting
You are not supposed to see the echo in the terminal which is used for flashing and monitoring, but in the other one
which is connected to UART1.
You are not supposed to see the echo in the terminal which is used for flashing and monitoring, but in the other UART configured through Kconfig can be used.