DIP Switches
DIP Switches
The
10 DIP switches on the component side of the PCB. Remove the brown
protection with a sharp knife.
There are 10 DIP switches plus 6 solder jumpers used for
configuring various optional functions of the Mode-S Beast.
Currently not all of them are used and so foreseen to further extensions.
On HW V1.0 (sold around May 2011), at minimum one
solder jumper is always needed at the TX-Data
multiplexer:
In most cases it is the solder jumper named USB,
which connects the serial output of the FPGA to the USB interface.
The other possible selections are Xport (Xp) and
BlueTooth (BT). Multiple connections are possible
for TX-Data. The default configuration for USB is normally done before shipping. The fallback position of the DIP switches
is all off, means towards the LED: 3MBit/sec over USB, no special
function activated.
In case of problems with the Mode-S Beast, I always
suggest falling back to this setting.
DIP Switches in short:
| DIP |
Function (if set to ON) | Recommened
Setting | | 1,2 | Baudrate
between FPGA and USB interface
| both
OPEN
| | 3 |
FW <=V1.21: AVR Format for transmission over Ethernet
FW >= V1.30: Binary Format | FW
<=V1.21: OPEN
FW >=V1.30: ON | | 4 |
DF11/17 filter: The Mode-S Beast only decodes DF-17 and DF-11
frames | OPEN | | 5 |
MLAT timestamp enablepix/mmic-voltagei.jpgpix/mmic-voltagei.jpgpix/mmic-voltagei.jpgpix/mmic-voltagei.jpg | ON |
| 6 | CRC check disable (for
DF-11 and DF-17) | OPEN (*1) |
| 7 | DF-0/4/5
filter: The Mode-S Beast does not decode those types (mostly used when
having performance problems) | OPEN |
| 8 | RTS handshake enable |
ON
(see note below) | | 9 |
1 pix/mmic-voltagei.jpgpix/mmic-voltagei.jpgpix/mmic-voltagei.jpgpix/mmic-voltagei.jpgbit forward error correction disable | OPEN
(*2) | | 10 |
Mode-A/C decoding enable | ON |
(*1) Only then use DIP#6 ON
position if you really know what it does.
(*2) 1 bit FEC may cause some
spurious decodes of non existing aircraft because the safety of the CRC
is decreased with it. If you are feeding databases, sharing networks or
similar, and if this is a matter for you, disable FEC (DIP#9=ON).
Otherwise, if you are just watching the air traffic, keep this switch
in OPEN position in order to have as many frames as possible. Those
just watching would never recognize but enjoy a bigger number of frames
beeing received and enjoy some smoother traces.
Technical
note: The Mode-S documents speak about even up to 5 bits
beeing correctible, but when I once tried a 3 bit error correction,
there were so many spuriouses that even just watching was not a
pleasure. I have no idea how a true good/bad decision on these frames
can be made successfully in order to make use of them.
DIP Switches in detail
| Baudrate |
SW1 | SW2 | Usage |
| 3 MBit/sec (*3) | open |
open | USB serial interface (with USB
over FT232R only) | | 921600
Bit/sec (*4) |
on | open | Bluetooth
interface, Lantronix Xport (Xport needs to be set to high performance
mode) | | 230400 Bit/sec |
open | on |
| | 115200 Bit/sec |
on | on | |
(*3) Until FW version V1.15 this baudrate was 1MBit/sec. It
became changed to 3MBit/sec with FW Version V1.21 and later
(*4) This
setting can be used when operating USB and Ethernet in parallel
Note that depending on your local
traffic rate the interface baudrate is the real bottleneck of your
system! So if you see a significant miss here, first introduce the
DF-0/4/5 filter with DIP #7, and if that does not help, switch on
DF17/DF11 filter with DIP#4. See also my comment here.
The Mode-S frames capability of the different baudrates is
about:
| Baudrate |
estimated number of Mode-S
frames per second maximum
in UDP format | estimated number of Mode-S
frames per second maximum
in binary format | | 3 MBit |
estimated more than 2000 | estimated more
than 4000 | | 921600 Bit/sec |
1100 | 2200 |
| 230400 Bit/sec | 550 | 1100 |
| 115200 Bit/sec | 300 |
600 |
These are very rougth estimations!!!
Mode-AC frames are output with lower priority, so if your interface is
already conguested with Mode-S frames, you will see less or no Mode-AC
frames.
Planeplotter
UDP Input Format
FW V1.21 and earlier (mostly obsolete) | SW3 |
| | disabled |
open | Standard output:
| 56
Bit Mode-S frames: | *02E99619FACDAE; |
| 112 Bit Mode-S frames: | *8D3C5EE69901BD9540078D37335F; |
| Mode-A/C frames: | *7700;
(Mode-A/C frame values are octal) |
| with MLAT information: |
| 56 Bit Mode-S frames: | @016CE3671C745DFFE7AB7BFCAB; |
| 112 Bit Mode-S frames: | @016CE3671AA88D00199A8BB80030A8000628F400; |
| Mode-A/C frames: | @016CE3671C747700;
(Mode-A/C frame values are octal) |
The distinction between Mode-S and Mode-A/C is done
using the length of the frame. |
| enabled | on | Only
necessary/used if
- Lantronix Xport is
used for network data transfer AND
- UDP data
transfer towards Planeplotter is used
(there
is also a COM port emulation for the Lantronix Xport, using TCP/IP
between the Xport and the computer, which does not need the 'AV' prefix)
laneplotter then needs a prefix 'AV' in order to distinguish
the data from other network data. Standard
output:
AV*02E99619FACDAE;
AV*8D3C5EE69901BD9540078D37335F;
AV*7700; with
MLAT information:
AV@016CE3671C7423FFE7AB7BFCAB;
AV@016CE3671AA8A800199A8BB80030A8000628F400;
AV@016CE3671C747700; |
Output Binary format
FW V1.30 and later |
SW3 | Usage (see also
output formats
chapter) | | AVR Format |
open | The output is in AVR format, see
above in "open" position | | Binary
Format | on | The output is
done in binary format, including signal level information.
This is the recommended mode when connecting the Mode-S Beast via
Ethernet to Planeplotter. |
| DF-11/DF-17 only | SW4 |
Usage | | all
standard data formats | open |
The Mode-S beast will decode all data formats that are currently used:
DF-0, DF-4, DF-5, DF-11, DF-16, DF-17, DF-18, DF20 and DF-21
Note:
DF-0, DF-4 and DF-5 can be masked with DIP#7 |
| only DF-17 frames | on |
Only DF-17 or DF-11 frames are decoded. This can be
used for example if you experience severe performance problems
on the serial interface. |
| MLAT enable | SW5 |
Usage | | MLAT
information off | open | AVR format only:
No MLAT information is provided, data frames are initiated with '*' |
| MLAT information on | on |
AVR
format only: MLAT information is provided using a 12MHz
(83ns resolution), all frames are initiated with '@'.
Note:
The binary format always contains MLAT information. |
| CRC disable | SW6 |
Usage | | CRC
on DF-11 and DF-17 | open |
DF-17 frames are checked for a total match of the CRC DF-11 frames are
checked for all but the lower 6/7 bits, which are the Interrogator ID
and not usable for checking | | no
CRC check | on | No CRC check
is done for any frame. This can be used in conjunction with the CRC and
biterror correction PC software driver or Planeplotter's FEC correction
in order to get a higher frame rate.
Important Note:
I do not know from which sources, but there are some which are telling
having DIP#6 in "ON" position. This quickly leads into interface
overload. It is recommended for only for special use. |
| DF-0/DF-4/DF-5 filter | SW7 |
Usage | | not
active | open | If your setup
is able to handle high load, this selection should be used |
| filter all DF-0, DF-4 and DF-5 frames | on |
These frame types are the ones with least useful information
and so they should be the first ones that can be masked in case of
interface or Planeplotter processsing overload. |
| RTS Handshake enable | SW8 |
Usage | | Hardware
handshake disable | open | Only
recommended with GUI software that does not enable hardware handshake. |
| Hardware handshake enable |
on | Always recommended.
Note:
This handshake is acutally not done between the GUI and the
FPGA, much better it is done exactly between the interface device and
the FPGA. |
The reason why this DIP is in OPEN in delivery
state is that the Beast always should output data, disregarding any
handshake setting. I am simply afraid of too many users that come back
with the note "The Beast does not output data...." just because of this
small DIP. After having seen that the Beast works, please enable RTS
handshake and see that it still works.
1
Bit FEC
disable | SW9 | Usage | | Forward
error correction enabled | open |
The CRC checksum of Mode-S frames allows a correction of
up to 5 bits. 1 Bit errors are those appearing most often and are
corrected with this feature by the Mode-S Beast for DF-11 and
DF-17/DF-18 frames | | disabled |
on | There is no bit error correction
done in the Mode-S Beast. | |
| Important Note:
Since FEC lowers the error
detection rate by nature, those users feeding databases or sharing
networks that observe every single occurance of ICAO IDs, may decide
having FEC disabled. Such users that only watch traffic as a spotter
should turn FEC on for a maximum frame rate. |
| Mode-A/C frame decoding | SW10 |
Usage | | disabled |
open | No Mode-A/C frames are decoded by
the Mode-S Beast | | enabled |
on | Mode-S Beast also decodes Mode-A/C
frames Frame format, see DIP#3 |
|
