ANT Forum

Hi,
I have the chip NRF24AP2, and I have signal clock from MCU (32768Hz in XC32K1 pin, pin XC32k2 is not connected), but when I put the command Enable Crystal (0x6D) after the startup message, the reply is INVALID MESSAGE (A4 03 40 12 6D 28 - hex). I'm doing wrong or is there another way to active external 32.768kHz clock?

Thanks for the help      

There is a slight contradiction in our documentation. The ANT Message Protocol document, section 9.5.2.16, indicates that the Enable Crystal (0x6D) is only for using an external crystal (not an external clock source). However the AP2 datasheet indicates that the command is needed for an external clock source as well.

The correct answer is that that the Enable Crystal command is ONLY needed for an external crystal and is not needed for an external clock source. So in your case, you do not need to send this command at all.

As long as you ensure that the external clock signal is toggling BEFORE initializing the AP2 chip, the clock should be detected automatically. If the AP2 initializes properly and accepts commands, you know it is working properly.      

I doing the good way, the problem is the message TX, I have a error in a position the filter (must be 0 but I put other number). After I correct this error, the command is accept.