MTK3339 GPS

[RobG 1,892]

Will do in the next iteration, any socket suggestions?

[bluehash 1,581]

Micro SD for sure to keep the footprint small.

[dkedr 31]

I wrote some code to modify which NMEA sentences the GPS module spits out and their frequency.

 

If you disable some the logger will have less data to chew through and can spend more time sleeping.

 

I should probably mention that it uses the button on P1.3 to select which one of the 8 available sentences comes out. I'm using hardware debounce so it might skip a few sentences if you don't debounce the pin.

 

Modifying the code will allow you to select any combination.

main.c

[SugarAddict 227]

a part/value list would be nice?

[RobG 1,892]

BOM:

IC1 - MSP430G2553IPW20
IC2 - 25AA640A-I/ST
IC3 - 1117-3.3 LDO, SOT89, Vout on the middle pin

MCU reset
R1 - 47k 0805
C5 - 1n 0805

LED1-LED4* - 0805 (cathodes are next to vias)
R2-R5* - current limiting resistors, I am using 330 0805
*LED1 and LED4 are connected to the same signal, so only one is needed.

C1 - 4u7 or 10u/6.3V, 3216/A package tantalum or ceramic 4u7/6.3 0805
C2 - 4u7 or 10u/10V, 3216/A package tantalum or ceramic 4u7/10 0805. Voltage depends on the supply.

C3*, C4, C6 - 0.1u 0805
L1* - chip bead inductor 120ohm/100mA 0603 (I am using 120ohm/350mA BK1608HM121)
*If you don't have inductor handy, you can short it with 0ohm resistor. In that case, C3 is not needed.

D1, D2 - do not use, MTK3339 has an internal diode. Short D1with 0ohm resistor when using on-board battery

[RobG 1,892]

Just FYI.

When you decide to use different EEPROM than listed (25AA640A-I/ST,) make sure TSSOP package matches SOIC/DIP pinout (Vcc at pin 8.)

There are some older EEPROMs that have different pin layout, including earlier version of 25AA640A, 25AA640.

Even 25AA640A comes in this weird layout, it's called X/ST.

 

BTW, Eagle's Microchip part 25* 25AA040ST is incorrect, 040 has that weird pinout. What a mess.

[AZ0114 0]

How would i go about parsing the NMEA sentences assuming im not using the LCD but a UART connection of the MSP430G2553 using PuTTY serial com.

[bluehash 1,581]

How would i go about parsing the NMEA sentences assuming im not using the LCD but a UART connection of the MSP430G2553 using PuTTY serial com.

Do you want the MSP430 to parse the gps data or stream it to the PC?

[AZ0114 0]

Do you want the MSP430 to parse the gps data or stream it to the PC?

I want the MSP430 to parse the gps data. What im trying to do is take the RMC sentence, pull the latitude and longitude, and then store it for further processing.

[bluehash 1,581]

I want the MSP430 to parse the gps data. What im trying to do is take the RMC sentence, pull the latitude and longitude, and then store it for further processing.

Rob's first post in this thread parses the data. You can take that data and push it out the serial port using opossum's TinyPrintf code.

[AZ0114 0]

Rob's first post in this thread parses the data. You can take that data and push it out the serial port using opossum's TinyPrintf code.

Ok so bear with me on this im still fairly new to using the MSP's

1) The majority of my code comes from dkedr's post where i changed it to always send out RMC sentence

2) Does parsing the data allow me to seperate and store the NMEA sentence (i.e for lat x=dd y=mm z=sss)?

3) if so, and assuming this is the line to parse it, how would i integrate the line. $GPRMC,[time:hhmmss.ss],[data status:AV],[lat:ddmm.sss],[NS],[long:dddmm.sss],[EW],[speed over ground:knots],[true course:deg],[uTC date of fix:ddmmyy],[magnetic variation:deg],[EW],[mode]*;

 

[hashtag 1]

Rob's first post in this thread parses the data. You can take that data and push it out the serial port using opossum's TinyPrintf code.

I have a similar question, rather than pushing it out through a serial port is it possible to use the original post code with the logger code on the msp430? From what ive read the new version of the MTK has it's own datalogging.

[bluehash 1,581]

I have a similar question, rather than pushing it out through a serial port is it possible to use the original post code with the logger code on the msp430?

Yes.

 

From what ive read the new version of the MTK has it's own datalogging.

 

Could you provide a link? Thanks!

[hashtag 1]

Yes.

 

 

Could you provide a link? Thanks!

http://www.adafruit.com/products/746

 

Two features that really stand out about version 3 MTK3339-based module is the external antenna functionality and the the built in data-logging capability. The module has a standard ceramic patch antenna that gives it -165 dB sensitivity, but when you want to have a bigger antenna, you can snap on any 3V active GPS antenna via the uFL connector. The module will automatically detect the active antenna and switch over! Most GPS antennas use SMA connectors so you may want to pick up one of our uFL to SMA adapters.

[bluehash 1,581]

Thanks!.. that's good to know.