Hisparc fpga & Software Aanpassingen
Adding methods to the DLL
DLL functions are the same as normal C functions. The only extra caveat is that the function prototypes must be specified in the header file (fpgaConfigApp.h).
[Deprecated] Changing the default location for the RBF-file
In the LabWindows code, in fpgaConfigApp.c there is a #define used to specify the file location. (Line 47 in the current version.)
Note that directory separators (backslashes) need to be escaped with a backslash to prevent the directory separators being interpreted as an escape character themselves. Practically this means that the file and directory names will have double backslashes instead of single ones.
This setting is no longer used. The RBF location is specified as a parameter to the autoFill function.
B. Documentatie voor GPS bit
In this document you will find the technical details for capturing the GPS timing configuration data as it was implemented as of June 2011.
HiSPARC III unit
This diagram illustrates the data path. The data is first acquired from the GPS module, and sent to the FPGA over an internal serial connection. The FPGA processes the data and parses out the relevant configuration bits, which are passed on to the PC by means of a USB connection between the two. From there the LabVIEW application handles the interpretation of the data and acts accordingly.
GPS status message
The GPS board sends a one Pulse Per Second or PPS, containing several messages with various data. The type of message is defined by the first three bytes of the message. In the case of the configuration message, these bytes are 0x80, 0x8F and 0xAB. In this message, the 9th byte is the byte that contains the time configuration. The first two bits of this byte are the time setting (0 for GPS time, 1 for UTC time) and the PPS time setting (0 for GPS time, 1 for UTC time). Though a mixed setting is a possibility, under normal circumstances, both these setting should be set to either GPS or UTC time.
In the VHDL code, the extraction of the bits is done in the ‘GPS_STUFF’ block. The output signals that carry the configuration values are ‘UTC_TIME’ and ‘UTC_PPS’.
C. Overzicht blokschema FPGA code
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