Answer
The Vela IF820 is preloaded with EZ-Serial firmware which can be used in one of two modes
- Text API
- Binary API
Text mode API provides human readable commands that can be sent to the module over the UART, typically from a microcontroller or from a PC terminal program during development.
Commands take the form of short code, for example
- /rbt will reboot the module
- /bti will start a Bluetooth classic inquiry
- /s will start a scan for BLE adverts
The text mode API is particularly useful when first using EZ-Serial.
The binary mode API may be a better choice for production devices due to having a simpler parset/generator for the UART host. Binary mode uses a fixed packet structure for every transaction. Each packet is made up of the following
- 4 byte header
- optional payload
- checksum byte
For example a command to get the GAP device name might look like this
C0 00 04 10 6D
and the response might look like this
C0 15 04 10 00 00 12 45 5A 2D 53 65 72 69 61 6C 20 31 41 3A 32 31 3A 44 33 A0
The first four bytes are the header (command), the 00 00 represents success, the 12 45 5A 2D 53 65 72 69 61 6C 20 31 41 3A 32 31 3A 44 33 is the returned name and the final byte is the checksum.