[time-nuts] PRS 10 and serial port communication

Philip Zahariev philip_zahariev at yahoo.com
Mon Mar 7 19:56:30 EST 2016


Hello group,

I have significant progress with generator. And there were new questions :-)
Frequency was little bit higher than 10 MHz - after correction of PLL constants SP and MO now is just on spot. 

In documentation is not clear described what is active state of signal 1PPS_IN. I found that signal must be 1 and goes to 0 during PPS pulse. After experience with SERIAL line inverter this time was easy (and have free inverters). Opposite is situation of output 1PPS_OUTPUT - his state is 0 and goes 1 during PPS pulse :-)

1. I found that AD8 - Amplified ac photosignal is changing between 1.120 to 3.991 and any value are different than previous, sometimes jumps are more than 2.xxx (monitoring with RBMon) - Is this usual?

2. AD10 - Case temperature (10 mV/°C) has value 0.781 which means 78°C. I remember that temperature has to be below 40°C, but when mount 2 heatsinks from computer CPU (socket 370) temperature decrease to 67-68°C. Do I need to install fans (don't like noise) or increase size? Are this 40°C was measured with external thermometer or means that AD10 need to be lower than 0.4xx? 

3. Firmware of my device is 3.15. Before value for TO - Time-tag offset (1816) from RBMon has Red square. According manual in this version of firmware TO is not user changeable. Is it available file with new firmware version? Processor on device is MC68HC711E20CFN3 - that means I need to buy new empty processor and program it. What improvements was made in newer version of firmware?

Best regards
Philip



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