Multiwii Write GPS
Writes raw GPS data to the auto-pilot. The data is injected into the GPS stream.
Library
QUARC Targets/Communications/Multiwii
Description
The Multiwii Write GPS block uses the Multiwii protocol on the input stream to send a command to the aircraft to
write raw GPS data to the auto-pilot. The Multiwii Write GPS block sends a MSP_SET_RAW_GPS
message to the auto-pilot.
This block is designed to be used with blocking I/O. It is typically used with a stream connected to a serial port. To open the stream a Multiwii Connect block should be used.
The inputs to the block are whether there is a GPS fix, the number of satellites, the latitude and longitude coordinates, the altitude and the speed. The ground course cannot be set.
A copy of the stream is also output so that the Multiwii blocks may be chained together.
If an error occurs, then the block returns a negative error code at its err output. The Compare to Error block may be used to check for specific error codes. If the stream is not valid because it is not yet connected, the err output will be zero since this condition is expected and the validity of the stream may be checked using the con output of the Multiwii Connect block.
Helpful Hints
Other uses of this block
Although it is intended for use in the main diagram with the other Multiwii
blocks, the
Multiwii Write GPS
block may be used
with the Advanced stream blocks, even in an asynchronous thread.
Input Ports
stm
A reference to the stream created by the Multiwii Connect block. If a connection has not yet been established, then the err output of the Multiwii Write GPS block will be zero.
fix
A boolean value indicating whether a GPS fix has been obtained.
sat
A uint8 integer containing the number of satellites upon which the GPS measurements were made.
coord
A 2-vector containing the latitude and longitude coordinates respectively in radians.
alt
A scalar representing the altitude in metres.
speed
A scalar representing the speed in metres per second.
course
A scalar representing the ground course in radians.
Output Ports
stm
A reference to the stream. This output is merely a copy of the stm input. Providing this output makes it much easier to establish the execution order of Multiwii blocks in the diagram because Simulink generally executes daisy-chained blocks in sequence.
err
An int32 value indicating whether the message was sent successfully. This value will be positive if message was sent successfully. It will be zero if no message was sent. If an error occurs then this value is a negative error code. See Error Codes for the different error codes and their values. Use the Compare to Error block rather than the error code itself to check for specific error codes. To check for errors in general use the Compare to Zero block to check whether the err output is less than zero.
Parameters and Dialog Box
Write only when the input changes
Check this option to have the block only write new GPS data when the input changes. If this option is not checked then the block will write new GPS data every time it executes.
This option makes it easier to use the block, since it typically makes a Triggered Subsystem unnecessary when the option is checked.
Targets
|
Target Name |
Compatible* |
Model Referencing |
Comments |
|---|---|---|---|
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
||
|
Yes |
Yes |
Last fully supported in QUARC 2018. |
|
|
Rapid Simulation (RSIM) Target |
Yes |
Yes |
|
|
S-Function Target |
No |
N/A |
Old technology. Use model referencing instead. |
|
Normal simulation |
Yes |
Yes |
See Also
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