how to check the DM6467 DSP frequency?

a) straight forward exact method:

put an oszilloscope on the oscillator input and measure that signal.

then read the PLL register set and determine its multipliers and dividers.

finally calculate the resulting frequency.

b) method using some assumptions:

design a loop in a non modifying assembler fashin with a very well known cycle time.

execute that loop for a certain amount of outer cycles thus forming some few 10 to 100 ms.

capture some reference timer before and after, and calculate the time difference, then you can calculate the instructions per time unit.

but where is the assumption? the timer might be runded in DSP-BIOS. the setup for this has a hardcoded timer clock value - if this is correct then anything is fine.

since that timer probably relies on the very same time source as the core it will not check those external time source but only the PLL setup.

only with some true external reference time (e.g. a periodic trigger signal) such verification can be done, but you wont always have such a feature in a design or a test bed.

alternate understanding of the question:

when the UART runs correctly then the baud rate is roughly correct, thus the clock source is fine.

assuming different speed grades of the same SoC there is no means to determine the maximum allowed processor speed other than the information printed on top of the packaging. just never exceed that, else you will risk data corruption, sudden system halts (depending on voltage, temperature, power consumption and alikes) and frying your SoC.

the high level determination of processor speed on linux systems for PCs is done like that:

  cat /proc/cpuinfo

i dont have the option to check that right now. maybe that kernel feature is disabled by default for those embedded variant.

maybe you talked about the outputs of U-Boot or similar...

Thanks a lot! Only ARM core frequency can be displayed if we use "cat /proc/cpuinfo". I want to display the DSP core frequency. I don't know the DSP core frequency of the DM6467 in my hand.