topic Which clock to use for tDISKEW calculation in PowerQUICC Processors https://community.nxp.com/t5/PowerQUICC-Processors/Which-clock-to-use-for-tDISKEW-calculation/m-p/871925#M2707 <HTML><HEAD></HEAD><BODY><P>I am investigating an interface between the MPC8308&nbsp; and a&nbsp; 532MT/s DDR2 RAM and I would like to calculate the the total amount of allowed skew from MDQS to a corresponding MDQ signals tDISKEW.</P><P></P><P>The document MPC8308 PowerQUICC II Pro, Processor Hardware Specification<BR /> Document Number: MPC8308EC, Rev. 4, 12/2014</P><P>gives on page 11 a formular to calculate tDISKEW from a clock periode and the controller skew (see attached screenshot). However, it is not mentioned whick clock periode shall be used. Is it the MCK clock periode which in my case would be T=1/133MHz giving a tDISKEW of approx. +/-1ns? </P></BODY></HTML> Wed, 06 Mar 2019 08:32:06 GMT creinhold 2019-03-06T08:32:06Z Which clock to use for tDISKEW calculation https://community.nxp.com/t5/PowerQUICC-Processors/Which-clock-to-use-for-tDISKEW-calculation/m-p/871925#M2707 <HTML><HEAD></HEAD><BODY><P>I am investigating an interface between the MPC8308&nbsp; and a&nbsp; 532MT/s DDR2 RAM and I would like to calculate the the total amount of allowed skew from MDQS to a corresponding MDQ signals tDISKEW.</P><P></P><P>The document MPC8308 PowerQUICC II Pro, Processor Hardware Specification<BR /> Document Number: MPC8308EC, Rev. 4, 12/2014</P><P>gives on page 11 a formular to calculate tDISKEW from a clock periode and the controller skew (see attached screenshot). However, it is not mentioned whick clock periode shall be used. Is it the MCK clock periode which in my case would be T=1/133MHz giving a tDISKEW of approx. +/-1ns? </P></BODY></HTML> Wed, 06 Mar 2019 08:32:06 GMT https://community.nxp.com/t5/PowerQUICC-Processors/Which-clock-to-use-for-tDISKEW-calculation/m-p/871925#M2707 creinhold 2019-03-06T08:32:06Z Re: Which clock to use for tDISKEW calculation https://community.nxp.com/t5/PowerQUICC-Processors/Which-clock-to-use-for-tDISKEW-calculation/m-p/871926#M2708 <HTML><HEAD></HEAD><BODY><P>You are right, it means MCK clock period. tDISKEW is -1ns (min) to +1ns (max).</P><P></P><P>Regards,</P><P>Bulat</P></BODY></HTML> Wed, 06 Mar 2019 10:56:13 GMT https://community.nxp.com/t5/PowerQUICC-Processors/Which-clock-to-use-for-tDISKEW-calculation/m-p/871926#M2708 Bulat 2019-03-06T10:56:13Z