Protocol Support and Specifications
This information is provided for reference purposes only. Data is subject to change between products and firmware versions. Unless noted elsewhere, MicroStrain by HBK reserves the right to make changes to these values without notice.
If you are developing software which configures the 3DM-CV7, where possible, it should always obtain information from the device itself. Avoid hard-coding these values in your software.
Descriptor Sets
| Descriptor Value | Name | Base Rate |
|---|---|---|
| 0x80 | Sensor Data | 1 kHz |
| 0x82 | Filter Data | 1 kHz |
| 0x91, 0x92 | GNSS Data, Internal Receiver 1 / 2 |
|
| 0x93 | RTK Data | 0 (Data is transmitted as it is received) |
| 0x94 | External GNSS1 | 0 (Data is transmitted as it is received) |
| 0xA0 | System Data | 1 kHz |
Supported commands and data quantities (including descriptor sets) can be obtained programmatically via the Get device descriptors (0x01,0x04) and Get device descriptors (extended) (0x01,0x07) commands.
The actual base rate should be obtained using the Get Data Base Rate (0x0C,0x0E) command. It is strongly recommended to query the base rate directly from the device as it is model specific and could change with future firmware versions.
Anti-aliasing Lowpass Filter Support
The Lowpass Filter (0x0C,0x54) command can be used to configure the final low-pass filter on the following data quantities. Other quantities are unfiltered.
| Descriptor Set | Data quantity |
|---|---|
| Sensor Data | Scaled Accel (0x80,0x04) |
| Scaled Gyro (0x80,0x05) | |
| Scaled Mag (0x80,0x06) | |
| Scaled Pressure (0x80,0x17) | |
| EKF Filter Data | Compensated Acceleration (0x82,0x1C) |
| Comp Angular Rate (0x82,0x0E) | |
| Linear Accel (0x82,0x0D) |
Comm Ports
These ports numbers are used with the Comm Port Speed (0x01,0x09) command.
| Port | ID | Supported baud rates | Supported Protocols |
|---|---|---|---|
| UART 1 | 0x11 | 115200, 230400, 460800, 921600, 3000000 | MIP, NMEA, RTCM, SPARTN |
| UART 2 | 0x12 | 4800, 9600, 19200, 38400, 57600, 115200, 230400, 460800, 921600 | MIP, NMEA, RTCM, SPARTN |
| UART 3 | 0x13 |
Events
| Feature | Firmware Version |
|---|---|
| Event Tick Rate | 1 kHz / 1 ms period (always matches system data set base rate) |
| Max Triggers | 12 |
| Max GPIO Triggers | 4 |
| Max Threshold Triggers | 8 |
| Max Combination Triggers | 8 |
| Max Actions | 12 |
| Max GPIO Actions | 6 |
| Max Message Actions | 8 |
Event support can be determined programmatically using the Get Supported Events (0x0C,0x2A) command.