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not totally sure, you didn't run minicom from your development board, isn't it? If so try to run it from your development board. If minicom print garbage char too, maybe there's a hardware problem on the UART.
Try to check NMEA checksum, to be sure it's not the console displaying...
If there's parity check (but I don't think so in NMEA format), enable it to with "set_iflag (port, IGNPAR, 0)".
Pull and shake the cable since a bad connection is possible too.
Distribution: Debian /Jessie/Stretch/Sid, Linux Mint DE
Posts: 5,195
Rep:
This looks like a hardware problem.
Either the cable, voltage levels, grounding or the UART, OR the clock rate is off.
In the early days we used to have crystals on the board which sometimes started to oscillate in 3rd overtone, and that made all clock frequencies off by a factor 3.
Try to compare the ASCII codes from erraneous bytes or characters against the characters which should have been received. Maybe you can discover a pattern, for example, the 7th bit is always high, or instead of 01010101 the character you received is 10101010 (start bit problem) or 00110011 (clock problem)
not totally sure, you didn't run minicom from your development board, isn't it? If so try to run it from your development board. If minicom print garbage char too, maybe there's a hardware problem on the UART.
Try to check NMEA checksum, to be sure it's not the console displaying...
If there's parity check (but I don't think so in NMEA format), enable it to with "set_iflag (port, IGNPAR, 0)".
Pull and shake the cable since a bad connection is possible too.
This is a much more productive reply from yourself, thank you!
No, I didn't run Minicom from the development board, it wouldn't be able to support it.
I have, however, run Microcom and the same issue surfaces.
I'm reasonably certain that my application is sound anyway; as I have compiled an x86 version which works swimmingly on my development machine.
With regard to the NMEA sentence, it does provide a checksum and I do check for it, but it fails.
No parity checking unfortunately.
Quote:
Originally Posted by jlinkels
This looks like a hardware problem.
Either the cable, voltage levels, grounding or the UART, OR the clock rate is off.
In the early days we used to have crystals on the board which sometimes started to oscillate in 3rd overtone, and that made all clock frequencies off by a factor 3.
Try to compare the ASCII codes from erraneous bytes or characters against the characters which should have been received. Maybe you can discover a pattern, for example, the 7th bit is always high, or instead of 01010101 the character you received is 10101010 (start bit problem) or 00110011 (clock problem)
It is about as much fun as sudoku.
jlinkels
I like Sudoku! =;-)
After further investigation, I'm fairly sure this issue lies in the configuration of the UART's AMBA driver.
Depending on how I call getty in inittab has a huge effect on just how much of the sentence is displayed as it should be.
Since this issue, I have installed serial->USB->serial drivers within the kernel - things are looking up. =:-)
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