https://community.nxp.com/t5/Other-NXP-Products/NXP55S69-PowerQuad-documentation/m-p/1566150#M16070 <P>Hi, I'm interested to use the PowerQuad on the NXP55S69 but am struggling to find documentation.</P><P>Is there adocument somewhere describing its control registers and what's meant to happen when they're set?</P><P>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.</P><P>CMSIS arm_fir_q31 computes the 64 bit dot product and then shifts right by 31.</P><P>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.</P><P>Is this correct? Is there a configuration bit to set the PowerQuad's rounding behaviour?</P> Wed, 07 Dec 2022 18:23:17 GMT Malcolm2 2022-12-07T18:23:17Z https://community.nxp.com/t5/Other-NXP-Products/NXP55S69-PowerQuad-documentation/m-p/1566150#M16070 <P>Hi, I'm interested to use the PowerQuad on the NXP55S69 but am struggling to find documentation.</P><P>Is there adocument somewhere describing its control registers and what's meant to happen when they're set?</P><P>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.</P><P>CMSIS arm_fir_q31 computes the 64 bit dot product and then shifts right by 31.</P><P>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.</P><P>Is this correct? Is there a configuration bit to set the PowerQuad's rounding behaviour?</P> Wed, 07 Dec 2022 18:23:17 GMT https://community.nxp.com/t5/Other-NXP-Products/NXP55S69-PowerQuad-documentation/m-p/1566150#M16070 Malcolm2 2022-12-07T18:23:17Z https://community.nxp.com/t5/Other-NXP-Products/NXP55S69-PowerQuad-documentation/m-p/1566691#M16071 <P>Hello&nbsp;<a href="https://community.nxp.com/t5/user/viewprofilepage/user-id/209704">@Malcolm2</a>&nbsp;</P> <P>About&nbsp;<SPAN>PowerQuad description, please see "Chapter 49: LPC55S6x/LPC55S2x/LPC552x PowerQuad DSP<BR />Coprocessor and Accelerator" of UM11126.</SPAN></P> <P><SPAN>And there is Application notes about PowerQuad:</SPAN></P> <P><A href="https://www.nxp.com.cn/docs/en/application-note/AN12383.pdf" target="_blank">https://www.nxp.com.cn/docs/en/application-note/AN12383.pdf</A>&nbsp;&nbsp;</P> <P><A href="https://www.nxp.com.cn/docs/en/application-note/AN12282.pdf" target="_blank">https://www.nxp.com.cn/docs/en/application-note/AN12282.pdf</A>&nbsp;&nbsp;</P> <P>&nbsp;</P> <P>BR</P> <P>Alice</P> Thu, 08 Dec 2022 08:39:00 GMT https://community.nxp.com/t5/Other-NXP-Products/NXP55S69-PowerQuad-documentation/m-p/1566691#M16071 Alice_Yang 2022-12-08T08:39:00Z