hJcRox
commented
7 years ago Hi again I found the problem. It seems to be a combination of a too short time-out ONEWIRE_TIME_MSG_HIGH_TIMEOUT = 15000_us and the Dallas Java 1-wire API sometimes running too slow. This caused CRC8 errors and "Error: first bit of byte timeout" traces in the Arduino monitor. After changing to ONEWIRE_TIME_MSG_HIGH_TIMEOUT = 150000_us everything seems to be perfect. No CRC8 errors and no error-traces in the monitor. Regards Jan
orgua
Hi I am trying to use a SparkFun Pro Micro @16 MHz with the OneWireHub 2.0. I am using the DS18B20 example with only one sensor to test. The problem I have is CRC8 errors when reading temperature, about 5-15% failure rate. I have tried various things to try to understand the problem and its cause:
I have made a calibration giving VALUE_IPL=13. Result text as below: DEBUG TIMINGS for the HUB (measured in loops): (be sure to update VALUE_IPL in src/OneWireHub_config.h first!) value : 875 nanoseconds per loop reset min : 491 reset max : 1097 reset tout : 5714 presence min : 22 presence low : 182 pres low max : 548 msg hi timeout : 17142 slot max : 154 read1low : 68 read std : 22 write zero : 34
Checked other VALUE_IPL as well, <12 not working at all. 12 and 13 about the same, and 14 is worse, but still working.
At CRC error it seems like my master (Windows with DS9490R) is reading all 0xff.
Most testing done with out serial debug but when on I get "Error: first bit of byte timeout" when CRC exemption
Tested a program a pure loop using micros() for the delay. With 9995 us between toggle a readout 50.0 Hz with my multi meter (not sure about its accuracy).
I have no oscilloscope and can not check the 1-wire waveforms.
Using 1.6.11 of Arduino.
I have tested with a real DS18B20 and it worked perfekt. No errors when running ~5000 temperature readings
Would be fine with some hints on how to continue debugging. The possibilities with this SW seems great. But it must be more reliable.
Regards Jan