GPS receiver restart PA1010D

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microguy
 
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GPS receiver restart PA1010D

Post by microguy »

I believe changing the module's output message type or types via a "$PMTK314,0..." message requires a reset or power cycle to take effect. This is not mentioned in the CD-PA1010D Data Sheet and is based only on my observations of several days or trial and many errors. --Jon

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adafruit_support_mike
 
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Re: GPS receiver restart PA1010D

Post by adafruit_support_mike »

That doesn’t match my experience working with the hardware. I’ve changed the output messages on the fly before.

Do you get an acknowledgment message after you send the command?

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microguy
 
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Re: GPS receiver restart PA1010D

Post by microguy »

Thanks for your comment. I bet you are correct. I would appreciate some more assistance. I want to demonstrate GPS to computer classes at a local middle school. I have tried for days to get the PA1010 to produce only the RMC messages by sending a setup sentence via I2C. The file Adafruit_PMTK.h includes these two lines:

Code: Select all

#define PMTK_SET_NMEA_OUTPUT_RMCONLY
  "$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29" ///< turn on only the
                                                      ///< GPRMC sentence
Using an online checksum calculator for GSP PMTK sentences I get a different checksum, though:

Command: $PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
*
With checksum: $PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,*05


I use an I2CDriver module and software to send the data with all characters converted to ASCII HEX-- P = 50, for example. I converted the numerals to ASCII also, 5 = 35. I can see on my logic analyzer that all hex values get transmitted properly to the PA1010 via I2C, with proper ACK returned for each. But I am stuck. Nothing seems to get the GPS module to go into RMC mode only. Are the values 0,1,0,0... converted to ASCII or do they simply get sent as raw hex values; 1 = 01, 2 = 02? I don't know.

The documentation does not provide enough details so I know exactly what to send and in what format. I monitor the serial output from the PA1010 and see the GPS messages, but they include GNGGA, GPGSA, GLGSA, GNRMC, GNVTG.

I only want the RMC data. My hardware requirements limit me to I2C communications with the PA1010. I hope you can help. Thank you. --Jon

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adafruit_support_mike
 
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Re: GPS receiver restart PA1010D

Post by adafruit_support_mike »

You do have to generate a new checksum for every version of the command you use.

You also need to end every command with "\r\n". The GPS module doesn't consider the command done until it sees those two characters.

When the GPS module sees a complete command, it will emit a reply message.

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microguy
 
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Re: GPS receiver restart PA1010D

Post by microguy »

I2C connections to PA 1010A GPS module.
Power off, reconnect to power (+5V)
Sequence of message to the PA1010D:
at 0.0 msec, 0x20 sent (device #0x10)
at 15 msec, start of I2C transmission, 51 command bytes sent, starting with 0x24 ($), ending with 0D and 0A (CR LF)
$PMTK314,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0*29 0D 0A (as per Adafruit software)
24 50 4D 54 4B 33 31 34 2C 30 2C 31 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2C 30 2A 32 39 0D 0A
Each byte acknowledged with ACK bit properly detected.
at 33.4 msec, UART data received as a continuous group of messages; GNGGA, GPGSA, GLGSA, GPGSV,GPGSV, GPGSV,GLGSV, GLGSC, GLGSV, GNRMC, GNVTG
at 1.4 sec, UART data received as packet of GNGGA, GPGSA, GLGSA, GNRMC, and GNVTG

I GIVE UP TRYING TO USE THESE GPS MODULES. --Jon

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