Prop on 24MHz crystal and Serial Comm
nicolad76
Posts: 164
Since I did not know what to do I decided to end the life of an old (very old) Ipod I had. I opened it and found some interesting pieces...
besides the micro hard drive which I will never be able to use with the Prop I found two interesting SMD quartz. 24 MHz I believe (there is a 24.000 printed on top of it).
I could not resist and I plug one of theme to my prop. I set PPLx4 which means the Prop should have run at 24x4=96 MHz....more or less...
The Prop run perfectly but the serial connection at 115200 stopped working. I used fullduplex. I put back 5MHz and PPLx16 and serial connection started working again.
I am wondering...since I am not an expert...in which way is the connection speed dependant on the crystal?
Well....I understand that if the Prop runs on few MHz I cannot reach high transmission speed...but if I can use 115200 at 5MHz x PPL16, then higher speed should still work...were am I wrong?
Grazie!!!!
Nicola
·
besides the micro hard drive which I will never be able to use with the Prop I found two interesting SMD quartz. 24 MHz I believe (there is a 24.000 printed on top of it).
I could not resist and I plug one of theme to my prop. I set PPLx4 which means the Prop should have run at 24x4=96 MHz....more or less...
The Prop run perfectly but the serial connection at 115200 stopped working. I used fullduplex. I put back 5MHz and PPLx16 and serial connection started working again.
I am wondering...since I am not an expert...in which way is the connection speed dependant on the crystal?
Well....I understand that if the Prop runs on few MHz I cannot reach high transmission speed...but if I can use 115200 at 5MHz x PPL16, then higher speed should still work...were am I wrong?
Grazie!!!!
Nicola
·
Comments
The PLL output stages 8x and 16x are not switched off and as they are driven out of specs the will produce .... ???
Thanks!!!!