Clocking capabilities

Is it possible to provide two separate crystal oscillators running at different frequencies to the two SMMs on the Jetson?

Could you please provide more details of the question? What’s the meaning of SMM? What’s the necessary to use two crystal?

Correction: it should be ‘SM’ instead of ‘SMM’, as Nvidia keep changing the names of their achitectural components. It stands for ‘Streaming Multiprocessor’ (formerly ‘Streaming Multiprocessor Maxwell’). A Streaming Multiprocessor is what would be known in OpenCL as an execution unit - the finest grained component of the processor with an independent control path. Each SM has 256 CUDA ‘cores’, and there are two SMs in a GPC (‘Graphics Processor Cluster’) on the Jetson TX2. There is one GPC on the TX2.

As for the reason to provide two different crystal oscillators to the core, I am attempting to use the device as a time-to-digital converter, however, others may find the information useful for, e.g, running separate parts of the core at different frequencies to save power or gain optimal performance under local process variations.

From hardware perspective, TX2 has one and only external crystal as reference clock, all other internal clocks including gpuclock are generated with it.