2 replies to this topic

[AVH]

Hello, For my Master Thesis. I am currently working on a project to timestamp data received via a serial connection. Unfortunately I'm a bit of a newbie to hardware. The timestamp has to have a resolution of 0.1 microseconds and has to be synchronised to UTC within nanoseconds. For this purpose the netduino plus is connected to a GPS Disciplined Oscillator outputting a 10mhz CMOS signal. With this application and setup in mind, some questions came up: - Is the Netduino Plus able to count a 10mhz signal using c#-code? - Will it have enough processing power to read a data string via serial connection, time-stamp it and sent it by an Ethernet connection while it is also keeping time(pulse counting)? I have been reading the posts on this forum for a while to be able to answer these questions, unfortunately without success. Any help is appreciated, Andy

[VBB]

The jitter on the serial communications will far exceed your time-stamp resolution in any case. I think you will have to have a deterministic clock microcontroller pre-processor, for example a PICMICRO, with very carefully designed assembler to read the 10Mhz signal either with a counter peripheral or probably better to have a TTL clock divider and read that. You could then mix your input serial stream with a timestamp probably on a byte by byte interleaved basis. ie one byte input data, one byte time stamp, .. You could then stream the resulting time-stamped serial into the netduino to parse the mixed data stream and send on up over the internet. The netduino will have the buffering and performance to post process and format the data but nothing short of assembler will be able to handle 100 nanosecond resolution. - JC

[Saturnim]

Probably you can to use internal counter of processor to measuring pulse. You should to read "Beginer Guid " ebook from GHI ,chapter 28 "Register access" . In this Chapter you have described exactly yours problem - counting high speed signals. But GHI is using other processors from NXP and example code will not work. You should to read datasheet of processor which you are using and then to write code.