UART

Serial Parameters

  • **Baud rate: **115200

  • Data bits: 8

  • Parity: None

  • **Stop bits: **1

  • **Flow control: **None

⚠ Ensure that the host controller (MCU or PC) uses the same configuration for proper communication.

Data Packet

Header

Packet Size

Data

Checksum

Byte Length

3

2

2+

1

Content

ICA

id+data_size+data

Description

“ICA”
Fixed 3-byte header

High byte first, low byte next. Indicates the length of all data bytes following this field.

ID refers to command ID; data_size = length of data; data = payload

Calculated checksum

Note: A single data packet can contain multiple data objects, but the IDs must not be duplicated.

Communication Process

Communication consists of read and write operations.

After each command is sent, the device returns an ACK response, reflecting the result of the last command.

Command IDs

Command

ID

Description

Notify

0

Sent by device; the host only needs to check this command field

Write

1

1 byte: target register address

Read

2

2 bytes: address + data length

*Data

10

Used together with Write command; cannot be used alone

Response Codes

Code

Meaning

Notes

0

Success

Command executed successfully

1

Packet timeout

Packet not received continuously; gap between segments too long

2

Data too long

Exceeds buffer capacity

4

Checksum error

Packet received but checksum failed

7

Invalid command

No such command

8

Missing data

Incomplete data in received packet

9

Register error

Invalid or non-existent register

10

System error

Device not fully booted, or internal error during communication

11

Data type error

Invalid data type received

Error Conditions:

  • **Packet Timeout: **Occurs if a full packet is not received continuously. If the sender splits the packet into segments, long gaps between segments will cause this error.

  • Checksum Error: Occurs when the packet is received but checksum does not match. This may be caused by coding issues in the sender or interference during transmission.

  • **System Error: **Occurs if the system is not fully booted or an internal fault happens during communication.

  • Partial Header: If the first 5 bytes (header + packet size) are not completely received, no error is triggered. After timeout, the device will ignore the packet.

Communication Example

Host reads a device register value

Host sends: 49 43 41 00 05 02 02 00 01 D7

  • 49 43 41: Fixed packet header ICA

  • 00 05 ：Packet length

  • 02 02 00 01 ：Command details

     `02`: Command ID = Read

 `02`: Data length

 `00 01`: Read from address `0x00`, size = 1

  • D7 ：Checksum

Device replies：49 43 41 00 07 00 01 00 0A 01 02 E2

  • 49 43 41: Fixed packet header

  • 00 07 : Packet length

  • 00 01 00 : Response command

     ID = 0 (response)

 Data length = 1

 Data = 0 (status OK)

  • 0A 01 02: Data command

      ID = 10 (data)

  Data length = 1

   Data = 02

  • E2: Checksum