Marc Boscher

MC1321x RF problem when moving from 62.5 KHz to 8 MHz as clockout

Discussion created by Marc Boscher on May 12, 2008
Latest reply on Jun 11, 2008 by Marc Boscher
Hi,

I'm trying to increase the clock output of the modem in the MC1321x so that I can use it as clock input for another external MCU. The original setting from the Beekit myWirelessApplication sample code is:

- #define CLOCK_OUT_SETTING   0x7E85 (nv_data.h), which outputs 62.5 KHz out of the modem
- NV_ICGC1 = 0x18 (nv_data.c), which sets the oscillator as low frequency range (FLL loop prescale factor P is 64)
- NV_ICGC2 = 0x20 (nv_data.c), which sets the multiplication factor to 8

So the MCU will run at 62.5 KHz * 64 * 8 = 32 MHz, which is what we want


Now I would like to output 8 MHz from the modem instead. I've changed the above settings to:

- #define CLOCK_OUT_SETTING   0x7E81 (nv_data.h), which outputs 8 MHz out of the modem
- NV_ICGC1 = 0x58 (nv_data.c), which sets the oscillator as high frequency range (FLL loop prescale factor P is 1)
- NV_ICGC2 = 0x00 (nv_data.c), which sets the multiplication factor to 4

So the MCU will run at 8 MHz * 1 * 4 = 32 MHz

The FLL locks correctly and the hiwave debugger confirms a bus frequency of 16 028 535 Hz

But RF communication is not working at all. I am simply sending broadcast messages to a receptor and none of the packets are being picked up. If I use the original settings (62.5 KHz output), everything is fine, if I used the new settings, nothing gets through.

Did I forget some settings here? Any ideas?

Cheers!
Marc



Message Edited by MarcB on 2008-05-12 04:44 PM

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