Hi, I'm interested to use the PowerQuad on the NXP55S69 but am struggling to find documentation.
Is there adocument somewhere describing its control registers and what's meant to happen when they're set?
Looking the implementation of CMSIS arm_fir_q31 broadly suggests how the FIR filtering mode can be operated but trying to use it I find there appears to be a rounding discrepancy.
CMSIS arm_fir_q31 computes the 64 bit dot product and then shifts right by 31.
So far as I can make out, the PowerQuad computes the 64 bit dot product, adds a rounding constant of 0x40000000 and then shifts right by 31. Which is not the same behaviour.
Is this correct? Is there a configuration bit to set the PowerQuad's rounding behaviour?
