Time-Appliances-Project / Time-Appliances-Project/Time-Card
Time in GPZDA on the NMEA serial port is incorrect
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- Dominant language
- C
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Description
The time reported in the $GPZDA NMEA message on the NMEA serial port is incorrect. It returns GPS time instead of UTC.
The upper part shows the G*ZDA message from the Time Card, while the lower - reported by the UBX module (on the UBX serial port)
$GPZDA,144310.00,09,08,2022,00,00*66
$GPZDA,144311.00,09,08,2022,00,00*67
$GPZDA,144312.00,09,08,2022,00,00*64
$GPZDA,144313.00,09,08,2022,00,00*65
$GPZDA,144314.00,09,08,2022,00,00*62
$GPZDA,144315.00,09,08,2022,00,00*63
$GPZDA,144316.00,09,08,2022,00,00*60
$GPZDA,144317.00,09,08,2022,00,00*61
$GPZDA,144318.00,09,08,2022,00,00*6E
───────────────────────────────────────────────────────────────────────────────────
NT����$GNZDA,144155.00,09,08,2022,00,00*7B
MT����$GNZDA,144156.00,09,08,2022,00,00*78
LT����$GNZDA,144157.00,09,08,2022,00,00*79
KT��s�$GNZDA,144158.00,09,08,2022,00,00*76
JT��^$GNZDA,144159.00,09,08,2022,00,00*77
IT��I$GNZDA,144200.00,09,08,2022,00,00*78
HT��3$GNZDA,144201.00,09,08,2022,00,00*79
GT��($GNZDA,144202.00,09,08,2022,00,00*7A
FT��� 8$GNZDA,144203.00,09,08,2022,00,00*7B
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by tracing the NMEA serial-port path that emits GPZDA/GNZDA and compare its time source with the UBX serial-port output. Confirm the expected UTC-versus-GPS offset using the supplied captures, then verify that emitted ZDA timestamps match UTC and that the existing serial output remains valid.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- embedded-iot
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 35/100