Samsung SCS-2U01 GPS Logs and Possible Tamper Switch

Written 2011-03-12

Tags:SCS-2U01 GloNav GPS 

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First off, there might be a tamper switch located under the GPS shield. Note the bottom-left corner of the shield connection. There is a small island of metal that isn't connected with the rest of the shield area. Normally this wouldn't be good for shielding, and if you test with a multimeter, the shield does make a good connection to this point. I've added a copper wire to mine just in case.
GPS BaseBand

Now on to the serial logging. The GPS processor here is an STR711. The datasheet is available from ST here: http://www.st.com/stonline/books/pdf/docs/10350.pdf. The STR711 is an ARM7TDMI with 4 UARTs, SPI, I2C, internal flash, USB, CAN, and internal RAM. 3 of the UARTs didn't appear to have anything on them, but UART0 (2 pins clockwise from the orientation dot) are communicating at 115200 baud. On powerup, the GPS emits:

"GloNav Ltd (c) 2007.  GN_GPS_Nav_Lib:  2.07.11-080813-000-0000  Aug 13 2008 14:14:31    528"

Here's what I'm guessing is a packet from gps to board cpu with some satellite stats:
#DBRM 14      66040 1  145   75 13 &05
#RMCH  0  0  0  0  0  0 0000   0     0     0     0 0     0      0       0 0000          0          0  0000    0  0 0   0 &AA
#RMCH  1 29  0  0 13  0 7000   0     0     0     0 3    32      0   91697 2D4E  483655680     -14531  AD07   61  0 0 -99 &02
#RMCH  2  0  0  0  0  0 0000   0     0     0     0 0     0      0       0 0000          0          0  0000    0  0 0   0 &AC
#RMCH  3 29 27  0 13 32 7012   1     0     0     0 5   540      0   92042 4886 -421134336      10427  0A4C   16  0 0  -2 &F2
#RMCH  4 29 27  0 11 32 7012   1     0     0     0 5   539      0  174817 B1AA -471597056       6117  9433   36  0 0  -2 &1E
#RMCH  5 29 27  0  0 32 7012   1     0     0     0 5   516      0  174878 3F8B  -14876672       5187  3946   36  0 0  -5 &06
#RMCH  6 29 27  0 13 16 7012   1     0     0     0 5   444      0  257759 1780  479068160       6095  26D8   15  0 0   0 &F5
#RMCH  7 29 27  0 13 32 7012   1     0     0     0 5   702      0   91942 3F55   32702464        170  C629   16  0 0  -3 &C2
#RMCH  8 29 27  0 12 16 7012   1     0     0     0 5   443      0  257469 C727   25231360     -14966  0E2B   55  0 0   0 &0F
#RMCH  9  0  0  0  0  0 0000   0     0     0     0 0     0      0       0 0000          0          0  0000    0  0 0   0 &B3
#RMCH 10 29 27  0 12 32 7012   1     0     0     0 5   558      0  174451 4D28  433192960     -12729  E500   36  0 0  -3 &2B
#RMCH 11 29  0  0  0  0 7000   0     0     0     0 3   555     44  610216 6202 -473300992      65600  22E5   89  0 0 -99 &03
#RMCH 12 29  0  0  0  0 7000   0     0     0     0 3   555     44  610221 0E28  -22347776      -2170  A3C4   89  0 0 -99 &09
#RMCH 13 29  0  0  0  0 7000   0     0     0     0 3   555     44  610225 BA72  428605440     -64071  3958   89  0 0 -99 &1F
#DBTT      66040 1 0 0 0 1855 510 0490 0081 &CE
#INFO 0  Ham1A_Rom5 510 E510P052 Rel Sep 16 2009 10:36:54     MP07 TYNDALL  16368 RTC &AF
#INFO 1  66  16   2   0   2      0     0    61     0     0     0     0   0   0   0   1 &CC

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