Hi.
I have made a first PCB design with Length Tuning, for the tracks that go to an SDRAM connected to an RT1020 Cortex M7 500Mhz microcontroller.
I'm not sure I calculated it well.
To calculate the total length of the track, do we have to count the thickness of the PCB when there are vias on that track?
In the screenshots attached, there are some tracks that go all on the TOP side without vias, and the others go on the Bottom side, with vias on the pins of the SDRAM, and vias on the pins of the Microcontroller.
For tracks with double via, I subtracted to the length of the track, 3.2mm (1.6mm thickness of PCB for each via).
Is this correct ?
I do not think Eagle automatically calculates it, because I have not seen Eagle request it.
Anyway, I'm beginning to suspect that the track length of the data bus does not have to be tuned to the track length of the address bus, but they have to be the same length for each bus, but I'm not sure.
Nor is it clear to me if the control lines should be tuned to each other, or also to the same length as the bus tracks.