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 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. Supports 16 channels (11 bits of precision per channel), plus frame loss and fail-safe flags.

---

Data structure description

sbus_flag_t

Description: SBUS flag structure.

• ch17: Digital channel 17 status

• ch18: Digital channel 18 status

• frame_lost: frame loss flag

• failsafe: fail-safe flag

sbus_dev_t

Description: SBUS device handle type.

---

Function interface description

sbus_dev_t sbus_create(int uart_id);

Function: Create SBUS device instance and configure UART parameters.

parameter:

• uart: UART device id, supports 1 ~ 4, represents uart1 ~ uart4

Return Value:

• Success: Returns SBUS device handle

• Failure: Return NULL

---

void sbus_destroy(sbus_dev_t dev);

Function: Destroy the SBUS device instance and release resources.

parameter:

• dev: SBUS device handle

---

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

Function: Set the value of the specified channel.

parameter:

• dev: SBUS device handle

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

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

Return Value:

• 0: Success

• -1: failed

---

int sbus_set_all_channels(sbus_dev_t dev, uint16_t *channels);

Function: Set the values ​​of all 16 channels.

parameter:

• dev: SBUS device handle

• channels: Array containing 16 channel values

Return Value:

• 0: Success

• -1: failed

---

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

Function: Set the SBUS flag.

parameter:

• dev: SBUS device handle

• flags: flag structure pointer

---

void sbus_get_flags(sbus_dev_t dev, sbus_flag_t *flags_out);

Function: Get the current SBUS flag.

parameter:

• dev: SBUS device handle

• flags_out: Structure pointer used to store flag bits

---

int sbus_send_frame(sbus_dev_t dev);

Function: Send SBUS data frame. Encode the currently set channel value and flag bits into a 25-byte SBUS frame and send it through UART.

parameter:

• dev: SBUS device handle

Return Value:

• 0: Success

• -1: failed

---

void sbus_set_debug(sbus_dev_t dev, bool val);

Function: Set debugging mode. When sending a frame in debug mode, the decoded channel value and flag bit will be printed.

parameter:

• dev: SBUS device handle

• val: true turns on debugging, false turns off debugging

---

Usage example

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

Note:

1. The corresponding UART TX pin needs to be configured through FPIOA before use.