We are looking at using a wilink8 based wifi module, attached to our am3354 which has a real time clock. Ideally, we would like to avoid having a separate 32khz oscillator, and to just use the RTC oscillator that is built into the processor. I'm concerned however about the note in the trm, Which says:
6.2.4 Output Clock Characteristics
NOTE The AM335x CLKOUT1 and CLKOUT2 clock outputs should not be used as a synchronous clock for any of the peripheral interfaces because they were not timing closed to any other signals. These clock outputs also were not designed to source any time critical external circuits that require a low jitter reference clock. The jitter performance of these outputs is unpredictable due to complex combinations of many system variables. For example, CLKOUT2 may be sourced from several PLLs with each PLL supporting many configurations that yield different jitter performance. There are also other unpredictable contributors to jitter performance such as application specific noise or crosstalk into the clock circuits. Therefore, there are no plans to specify jitter performance for these outputs
The requirement of the WiLink8 is to have an input clock jitter of no worse than +/-250ppm
We would like to output the clock through XDMA_EVENT_INTR1.
Is using this output to drive the 32khz clock to WiFi a reasonable choice? Has anyone done it successfully in production? Of course we will put an independent oscillator on the board, just in case, but I'd like to start off assuming the that am335x output will work for this, which will save cost and power.