The following interface communication options are available. Their technical details will be described in this chapter:
All the digital IOs have internal pull-down resistors in normal operation compliant with ESD (IEC 61000-4-2 level 4).
The time pulse function provides a one pulse per second (pps) signal. Once the sensor has received any GNSS signal information, the 1 pps signal will adjust itself to each second in time. The raised edge of each pulse will be aligned to the top of GPS time seconds. The duty cycle is 10 %, meaning that the pulse width is 100 ms. The message is available in the raw GNSS1 output on port 20010.
The time mark provides an accurate measurement of the time at which a pulse is detected on the port 20010. The maximum time mark frequency is 5 Hz, that is at most one mark per 200 ms interval.
|
Parameter |
Symbol |
Min |
Max |
Units |
|
Baud rate |
Fbaud_rate |
9600 |
4000000 |
bit/s |
|
Transmit bit time |
tTbit |
1/Fbaud_rate - Tref_clk |
1/Fbaud_rate + Tref_clk |
- |
|
Receive bit time |
tRbit |
1/Fbaud_rate – 1/(16xTref_clk) |
1/Fbaud_rate + 1/(16xTref_clk) |
- |
The Ethernet MAC interface is provided via a RJ45 connector. The AR8033 Ethernet transceiver supports IEEE 802.3az standard.
|
Parameter |
Condition |
|
IP setup |
Static and Dynamic |
|
Speed |
10BASE-Te/100BASE-TX/1000BASE-T IEEE 802.3 |
|
Communication |
Full-duplex |
|
Cable Discharge Event |
±6 kV CDE protection |
|
Operation |
Limited to 140 meters of CAT5 cable |
|
Default IP address |
10.0.2.1 |
A USB2.0 interface is provided via a USB Type C connector. Not recommended as a power supply.
|
Parameter |
Condition |
|
Operation mode |
IEEE 802.11 ac/a/b/g/n |
|
Band support |
Dual band 2.4/5 GHz |
|
Default IP address |
10.0.1.1 |
|
Mode |
Station and access point |
The following connected interfaces can be used:
|
Interface |
Measurement |
Specification |
|
OBD-II |
Wheel speed |
500000 bitrate |
|
CAN |
Wheel speed |
500000 bitrate |
|
Serial |
Wheel speed |
50 Hz |
|
Interface |
Direction |
Function |
|
UART1 |
Output |
Baud rate 115200, 8 bits, no parity, 1 stop bit ASCII messages are output by default |
|
Input |
Configurable serial wheel speed RTCM3 correction data input |
|
|
TCP/IP network (Wi-Fi, Ethernet) |
Output |
Port 21000, ASCII messages are output by default. |
|
Output |
Port 20010, raw GNSS receiver 1 output (read-only). The configuration of the receiver cannot be changed. |
|
|
Output |
Port 20020, raw GNSS receiver 2 output (read-only). The configuration of the receiver cannot be changed. |
|
|
Output |
Port 23010, raw NTRIP data stream (read-only) |
|
|
Input/Output |
Port 80 (HTTP) configuration and logging interface |
|
|
Time Pulse |
Output |
Port 20010, 1 Hz 10% duty cycle, 3.3 V, the configuration cannot be changed. |
|
Time Mark |
Input |
Time signal |
|
CAN |
Input |
Configurable wheel speed |
Message structure
The default ASCII messages use the following framing format and general structure. Note that all the fields are separated by an ASCII 44 character “,”.
|
$FP,msg_type,msg_version,field3,field4,…,fieldN*CCrn |
|
|
$ |
Start character (ASCII 36). |
|
FP |
ASCII message identifier (ASCII 70 + 80). |
|
msg_type (field1) |
Message type, all capital letters (ASCII 65–90). |
|
msg_version (field2) |
Message version, decimal number (numbers 0–9, ASCI 48–57). |
|
field3 |
The structure of the message data is defined by the msg_type and msg_version fields. Each field can contain all printable 7-bit ASCII characters (ASCII 32–126), excluding the reserved characters ‘!’ (ASCII 33), ‘$’ (ASCII 36), ‘*’ (ASCII 42), ‘,’ (ASCII 44), ‘’ (ASCII 92) and ‘~’ (ASCII 126). Fields can be null (the empty string) to indicate absence or unavailability of data. |
|
field4 |
|
|
… |
|
|
fieldN |
|
|
*CC |
Checksum value obtained by applying XOR to all characters in the message. The value starts with a * (ASCII 42) and is followed by the checksum value in capital hexadecimal notation (numbers 0– 9 and letters A–F, ASCI 48–57 and 65–70). |
|
rn |
Message termination characters, CR an LF (ASCII 13 and 10). |
The data fields can be of the following types:
|
Type |
Description |
|
Numeric |
Decimal integer number, one of more digits (0–9) and optional leading ‘-‘ sign. |
|
Float (.x) |
Decimal floating-point number with x digits fraction part. One or more digits (0–9) , with fractional part separated by a dot (‘.’) and optional leading ‘-‘ sign. |
|
Float (x) |
Decimal floating point with x significant digits. One or more digits (0–9) with optional fractional part separated by a dot (‘.’) and optional leading ‘-‘ sign. |
|
String |
String consisting of allowed field characters. |