HCS08.
Are there any tools available to help selecting the crystal and PLL settings
for standard baud rates, and specifically the higher ones, up to 921600 baud?
Anders J
Hello,
I am having same problem and until now I have no solution. Only an external resonator on 29,4912 MHz (BUS clock will be 14,7456 MHz) http://cz.farnell.com/abracon/asem1-29-4912mhz-lc-t/mems-oscillator-29-4912mhz-smd/dp/1633615 But I will also be glad for some crystal and FLL solution if somebody has it.
Hello,
now I already upgrade my hardware with external oscillator of 29.4912 MHz and run it as clock source by code:
uint i;
// 29.4912MHz Oscillator
// Fbus = ( Fext * 1 / BDIV ) / 2 => 14.7456MHz
ICSC2_BDIV = 0b00; // 00 BDIV = 1
ICSC2_LP = 1; // 1 FLL is disabled in bypass modes
ICSC2_EREFS = 0; // 0 External Clock Source requested.
// wait for stability of oscillator
for ( i = 0 ; i < 10000 ; i++ );
ICSC1_IREFS = 0; // 0 External reference clock selected.
ICSC1_CLKS = 0b10; // 10 External reference clock is selected
My baud rate is 921600. I am using MC9S08QE16 device.
Minimum bus clock required for 921600 is 921600*16=14745600Hz.
You may use standard UART crystal frequencies like 3.6864MHz or 7.3728MHz and PLL multiply it to 14.7456MHz. Processor expert may help finding right PLL/FLL settings.