gadgetPool SeaTalk NMEA User manual

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
SeaTalk <-> NMEA
SeaTalk <-> RS232
Converter
Installation and Operation
Manual
To be used with AtMega1284p processor only
Hardware Version V 3.5
Software Version 2.00
Dec 2012

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
Contents
Credits / Warning / Disclaimer............................................................................................ 3
Function overview............................................................................................................... 3
NMEA Input..................................................................................................................... 4
Special NMEA-like configuration sentences.................................................................... 5
NMEA Output.................................................................................................................. 6
The $STALK sentence................................................................................................... 7
SeaTalk Input.................................................................................................................. 8
SeaTalk Output ............................................................................................................... 9
Collision detection.................................................................................................... 9
Same type of Data on NMEA & SeaTalk......................................................................... 9
SeaTalk Connection.......................................................................................................... 10
NMEA / RS232 Connection ...............................................................................................11
Input Jumper RS232..................................................................................................... 12
Input Jumper RS422..................................................................................................... 14
RS422 In -> RS232 Out................................................................................................ 15
Configuration settings....................................................................................................... 17
Options............................................................................................................................. 20
LCD Display.................................................................................................................. 20
Pushbutton.................................................................................................................... 21
Software update ............................................................................................................... 22
Bootstrap Loader Method.............................................................................................. 22
Circuit Diagram................................................................................................................. 23
SeaTalk & NMEA conversion Table .................................................................................. 24
Terminals & Connectors ................................................................................................... 25
ASCII Table....................................................................................................................... 27

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
Credits / Warning / Disclaimer
The Protocol converter is a
RESEARCH PROJECT.
It is used for research on data communication, computer communication and data
conversion on computers used on board boats.
Hard- and Software are still under development and have NOT been fully tested.
Malfunctions of the protocol converter and of any connected device are possible at any
time.
It is not an end user product and must not be used for navigation.
The protocol converter could cause damage to connected devices.
Liability cannot be accepted for any damages, personal injuries or malfunctions caused
by the converter.
There are no Seatalk technical specifications available from the manufacturer. I have used
the Technical Reference of the Seatalk protocol, compiled by Thomas Knauf GmbH.
See http://www.thomas-knauf.de/seatalk.htm .Thank you to Thomas Knauf for his work.
Do not use for navigation
An operating GSM mobile phone should not be placed within 2m of an
unshielded Seatalk/NMEA Bridge because of interference from the phone's
radio transmissions. If a phone is brought closer than this 2m distance, the
bridge may stop operating or data may become corrupted.
( Thank's John Blaiklock for testing )
Function overview
The converter interconnects two different data communication systems –SeaTalk
1
and
NMEA.
Information from the SeaTalk bus is transformed into NMEAData and sent to the
NMEA bus.
Information from the NMEAport is transformed into SeaTalk data and sent to the
SeaTalk bus.
Optionally information from both busses can be shown on a LCD display.
1
SeaTalk is Reg. Trademark of Raymarine Inc.

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
NMEA Input
Processing of NMEA data starts, when a complete NMEA sentence has been received.
If the received sentence contains a checksum, this checksum is used to check for
communication errors. If the checksum does not match the sentence, the received NMEA
sentence is discarded.
If the sentence does not contain a checksum, the sentence is always regarded as valid.
After complete reception of a NMEA sentence, this sentence is sent to the NMEA-Out port
of the converter Board and can be used by other NMEA devices.
(This function can be switched off by control setting –see below )
If the received sentence is known, the sentence information is extracted and processed. At
this time the following NMEA sentences can be received:
$xxRMC Speed over Ground, Course over Ground,
Latitude, Longitude, Time, Date
$xxVTG Course over ground
$xxGLL Position
$xxVHW Speed through water
$xxRMB Waypoint Information
$xxAPB Waypoint Information
$xxBWC Waypoint Information
$xxDBT Depth below transducer
$xxDPT Depth below keel
$xxMTW Water Temperature
$xxVLW Total / Trip Mileage
$xxHDM Heading magnetics
$xxHDG “ “
$xxZDA Date & Time
$xxVTG Ground speed
$xxVHW Compass
$xxVLW Trip mileage, Total mileage
$xxMWV Wind angle Wind Speed
$xxVWR Relative Wind Speed and Angle

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
Special NMEA-like configuration sentences
$STALK Special SeaTalk datagram
$SNBSE Board configuration
$COLCO SeaTalk Bus collision counter
$SWUPDATE Update board to new firmware
$SWVERSION Display firmware version number
Example
Enter : $SWVERSION<ENTER>
Result : SWVERSION*72
With LCD
$STVER,2.00,BRIDGE*45
2.00 = This board has Software Version 2.00
With LCD = Software is for board with LCD Display
BRIDGE = This Software is for SeaTalk Nmea BRIDGE
Example
Enter : $COLCO*45
Result: $IICOLLISIONS,000*11
$IIERRORS,0*27
No SeaTalk collisions so far.
No Buffer overflow errors so far.

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
NMEA Input
SeaTalk Input
NMEA Output
SeaTalk -> NMEA
translation
NMEA Output
All valid NMEA sentences –whether processed by
the converter or not –are forwarded to the NMEA-
Out port.. If the NMEA-Out port is busy, the
sentence is temporarily stored in memory and
transmitted as soon as the NMEA-Out port
becomes free.
The converter also continuously checks for new incoming SeaTalk data.
Incoming SeaTalk data is converted to NMEAData and transferred to the NMEA-Out Port.
The following NMEA sentences will be generated from incoming SeaTalk data :
$IIDBT Depth below transducer
Optional $IIDPT can be sent instead of $IIDBT
$IIVHW Speed t. Water
$IIMTW Water Temperature
$IIVLW Total / Trip Mileage
$IIMWV Apparent Wind angle & Wind speed
$IIMWV True Wind angle & Wind speed
$IIHDM Heading compass
$IIRMC Speed over ground, Course over ground,
Latitude, Longitude, UTC time, Date
Optional an additional $IIGLL sentence can be
sent for position information
$IIRSA Rudder angle
$STALK special SeaTalk datagram
$SNBSE special system configuration datagram

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
The $STALK sentence
The converter can process a special NMEA-like sentence.
With this special sentence any SeaTalk command can be sent to SeaTalk.
$STALK,cc,p1,p2..,pn*xx
cc = SeaTalk Command
p1 = Parameter1
p2 = Parameter 2
..
*xx = NMEAchecksum ( optional ) .
This special sentence will be sent to the NMEA Bus for every received SeaTalk datagram
–regardless as to whether it was recognised and processed or not.
( This function can be switch off by control setting –see below )

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
SeaTalk Input
NMEA Output
SeaTalk -> NMEA
translation
SeaTalk Input
When a SeaTalk datagram is received the system checks if this datagram is known and
can be processed. When the datagram is known, all parameters are extracted and stored.
Any unknown datagram is ignored.
(Exception: $STALK is sent even for unknown datagrams)
At this time the following SeaTalk datagrams are known.
00 Depth
10 Wind angle
11 Wind speed
20 Speed through water
21 Trip mileage
22 Total mileage
23 Water temperature
25 Total & trip mileage
26 Speed through water
27 Water temperature
30 Lamp brightness
50 Latitude
51 Longitude
52 Speed over ground
53 Course over ground
54 UTC time
56 Date
58 Latitude & Longitude
84 Compass heading
89 Compass ST40 heading
9C Compass heading & rudder position

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
NMEA Input
SeaTalk Output
NMEA -> SeaTalk
translation
SeaTalk Output
The converter periodically checks if any new data has arrived from NMEA, which have to
be sent to SeaTalk. New data is written to the SeaTalk bus only if the bus is not in use by
any other instrument. If the bus is in use, the converter waits for a while, and tries again.
Collision detection
Every single bit sent out to the SeaTalk bus is read back again and checked for successful
transmission. If the transmission was corrupted, the transmission is stopped immediately.
When the bus becomes free, the transmission will be started again.
At this time the following SeaTalk datagrams can be sent
00 Depth
10 Wind angle
11 Wind speed
20 Speed through water
25 Total & Trip mileage
27 Water temperature
30 Lamp intensity
50 Latitude
51 Longitude
52 Speed over ground
53 Course over ground
54 Time
56 Date
82 Target Waypoint Name
85 Navigation to Waypoint information
89 Compass ST40 heading
Same type of Data on NMEA & SeaTalk
Information available from like instruments on both Busses ( SeaTalk & NMEA ) are not
converted.
Example:
We have a depth sounder on the SeaTalk Bus and another depth sounder on the NMEA
bus.
So, on both sides depth information is available.
In this case no depth information in transferred from one bus to the other.
( If depth information is not updated within 30 sec. on one bus, sending to the other bus is
activated again. )

Valid only with © 2004-2010 All Rights Reserved http://www.gadgetPool.de
ATMega1284P processor © 2004-2010Alle Rechte vorbehalten FWallenw[email protected]
SeaTalk Connection
+12V DATA GND
There is a 3-Pin terminal for the connection to the SeaTalk bus.
Please double check for correct connection.
The board takes it’s power supply from +12V and GND.
+12V & GND MUST be connected, even if the SeaTalk bus is not needed.
A wrong connection could damage the converter or other devices on
the SeaTalk Bus.