100 nS ? The data rate is 10 Mhz ? or you just want that time resolution ?
BLE will not support a continuous stream of 10 Mhz data.
thanks for your reply
100 ns is the time resolution, which is what I used in version 1 of my project.
Version 2 is to be wireless, which is why I am considering BLE.
The time resolution doesn't have to be exactly 100 ns, as whatever it turns out to be can be scaled to match the rest of the system.
The data rate is about 25 bytes every 3.8 ms -> ~7 bytes per millisecond -> 56 bits per millisecond
That is as fast as the pair of accelerometers can provide data. Can BLE handle that?
The data is filtered and integrated, so a time stamp is essential.
The average data rate you pointed out can be easily supported by BLE, but I would like to point out that the minimum connection interval that can be set for a BLE connection is 7.5 ms. This implies that the minimum difference between any two data transfer cannot be less than 7.5 ms.
So when you say that you need to send 25-bytes every 3.8 ms, it will be more like send 50 (25+25) bytes every 7.6 (3.8+3.8) ms. This implies, in your case, one set of data will se received by the device 3.8 ms later than its original intended time.
Thanks for pointing out the minimum connection interval. That is not an issue, however, as each data set is to be time stamped at the time of acquisition. When the data set is actually sent is not important. I am considering storing the data in F-RAM and sending it later.
What I need help with is in setting up PSoC 4 BLE so that "time", with a resolution around 100 ns, can be read and applied to each data set as it is grabbed from the accelerometers via I2C polling.
From Document Number: 001-96201 Rev. *A page 11
For PSoC 3/PSoC 5LP, you can connect any digital signal from any source to the count/clock
input. The frequency of that signal is limited to the frequency range defined in the DC and AC
Electrical Characteristics (UDB Implementation) section in this datasheet. The count input must,
at most, be half the frequency as that of the clock input in any of the Counter Clock modes.
For PSoC 4, you cannot connect a clock signal to the count input.
What can be used for a 100 ns input to "count"?
1 of 1 people found this helpful
Use a Timer and feed its clock with 10 Mhz.
Why didn't I think of that!