Note

This is the documentation for the latest development branch and may refer to features that are not available in released versions. If you are looking for the documentation for a specific release, use the drop-down menu on the left and select the desired version.

SBUS HAL Interface Documentation

Hardware Introduction

K230 supports implementing the SBUS (Serial Bus) protocol through the UART interface. SBUS is a serial communication protocol commonly used in remote control receivers, using a 100kbps baud rate, 8 data bits, 2 stop bits, and even parity. It supports 16 channels (11-bit precision per channel), as well as frame lost and failsafe flag bits.

---

Data Structure Description

sbus_flag_t

Description: SBUS flag bit structure.

• ch17: Digital channel 17 status

• ch18: Digital channel 18 status

• frame_lost: Frame lost flag

• failsafe: Failsafe flag

sbus_dev_t

Description: SBUS device handle type.

---

Function Interface Description

sbus_dev_t sbus_create(int uart_id);

Function: Creates an SBUS device instance and configures UART parameters.

Parameters:

• uart: UART device ID, supports 1 ~ 4, representing uart1 ~ uart4

Return Value:

• Success: Returns the SBUS device handle

• Failure: Returns NULL

---

void sbus_destroy(sbus_dev_t dev);

Function: Destroys the SBUS device instance and releases resources.

Parameters:

• dev: SBUS device handle

---

int sbus_set_channel(sbus_dev_t dev, uint8_t channel_index, uint16_t value);

Function: Sets the value of the specified channel.

Parameters:

• dev: SBUS device handle

• channel_index: Channel index, range [0, 15]

• value: Channel value, 11-bit precision, typical range [172, 1811], mid value 1024

Return Value:

• 0: Success

• -1: Failure

---

int sbus_set_all_channels(sbus_dev_t dev, uint16_t *channels);

Function: Sets the values of all 16 channels.

Parameters:

• dev: SBUS device handle

• channels: Array containing 16 channel values

Return Value:

• 0: Success

• -1: Failure

---

void sbus_set_flags(sbus_dev_t dev, const sbus_flag_t *flags);

Function: Sets the SBUS flag bits.

Parameters:

• dev: SBUS device handle

• flags: Pointer to the flag bits structure

---

void sbus_get_flags(sbus_dev_t dev, sbus_flag_t *flags_out);

Function: Gets the current SBUS flag bits.

Parameters:

• dev: SBUS device handle

• flags_out: Pointer to the structure used to store the flag bits

---

int sbus_send_frame(sbus_dev_t dev);

Function: Sends an SBUS data frame. Encodes the currently set channel values and flag bits into a 25-byte SBUS frame and sends it via UART.

Parameters:

• dev: SBUS device handle

Return Value:

• 0: Success

• -1: Failure

---

void sbus_set_debug(sbus_dev_t dev, bool val);

Function: Sets the debug mode. In debug mode, the decoded channel values and flag bits will be printed when sending frames.

Parameters:

• dev: SBUS device handle

• val: true to enable debugging, false to disable debugging

---

Usage Example

Please refer to src/rtsmart/libs/testcases/rtsmart_hal/test_sbus.c

Notes:

1. Before use, the corresponding UART TX pin needs to be configured through FPIOA.