Timur Tabi timur@freescale.com wrote on 10/09/2009 17:26:29:
Joakim Tjernlund wrote:
Looking a bit harder at the table I don't understand some entries, where does the entries with dfsr != 1 come from? They don't look like any table in AN2919
They're all calculated. I entered the algorithm into a spreadsheet and determined every possible combination of DFSR and FDR. The values of DFSR==22 are for frequencies that are normally not published.
This calculation does not seem to match AN2919.
Suppose one used only Table 7(almost what we have if you exclude dfsr!= 1) Table 7 is valid for 1 <= dfsr <=5 so how about replacing the current dfsr with: #ifdef __PPC__ u8 dfsr; dfsr = (5*(i2c_clk/1000))/(100000); if (dfsr > 5) dfsr = 5; if (!dfsr) dfsr = 1; debug("i2c_clk:%d, dfsr:%d\n", i2c_clk, dfsr); writeb(dfsr, &dev->dfsrr); /* set default filter */ #endif