Forum Discussion
Altera_Forum
Honored Contributor
9 years ago --- Quote Start --- Have you read this? www.altera.com/literature/ug/altera_pll.pdf?gsa_pos=2&wt.oss_r=1&wt.oss=altera_pll (http://www.altera.com/literature/ug/altera_pll.pdf?gsa_pos=2&wt.oss_r=1&wt.oss=altera_pll) From the Cyclone V handbook:
Each Cyclone V PLL provides clock synthesis for PLL output ports using the M/(N × C) scaling factors. The
input clock is divided by a pre-scale factor, N, and is then multiplied by the M feedback factor. The control
loop drives the VCO to match fin × (M/N). For Cyclone V, each of M,N,C can be 1..512. So if your input clock is 50MHz (as an example), then with M=2, N=125, C=25 will give an Fout of 32KHz (ie, 50e6*2/(125*25)). --- Quote End --- Hi, The PLL output frequency only gives me lowest value to 1.1718Mhz, and can't go lower than that. Is there any other way to let me generate 32k from altera PLL? Thanks, Jeff