ChedderCheeser
Senior Member
hi all. I am going to be working with a icaxe 40X2 and a 4Mhz resonator. I am confused on this though... do I need any extra code to get the maximum speed out of it or... does it just.. automatically do it?
Resonator Confusions...
- Thread starter ChedderCheeser
- Start date
BillyGreen1973
Senior Member
have a read of the 'commands' manual under the command 'setfreq'. That should answer all your questions
You mean PICAXE-40X2I am going to be working with a icaxe 40X2
Internal or external? I'll assume externaland a 4Mhz resonator.
You need to use the SETFREQ command to use anything other than the internal 8MHz oscillator although unfortunately it will automatically go back to 8MHz if there's a problem with the external resonator (which is a pain on battery supplies or ones with big capacitors). the PICAXE-40X2 has an option for an internal oscillator at 16MHz so unless you need the extra timing accuracy offered by an external one, I suggest you use the internal one.I am confused on this though... do I need any extra code to get the maximum speed out of it or... does it just.. automatically do it?
- For internal 16MHz, use 'SETFREQ M16'
- For external 16MHz using a 4MHz resonator and 4xPLL, use 'SETFREQ EM16'
- For external 4MHz on a 4MHz resonator, use the same as above but then disable the PLL (see PLLEN bit in OSCTUNE register)
Absolute_Beginner
Member
A supplementary question relating to external resonators/crystals ad PICAXE 40X2 chips:
The manual says if you use an external resonator then it must be for a quarter of the desired operating frequency. Does this mean that the only way to get say 32MHz operation is with an 8MHz external resonator ? And with an 8MHz external resonator you can get 32 MHz operation, and [as well as neglecting frequencies for the external resonator is not absolutely required (ie, k31, k250, k500,m1, m2, m4, m8, m16)], the only other frequency control you can have is at 8MHZ with the external resonator described by nickab12 above ?
I am sorry this so clumsily phrased: with an 8MHz resonator and a 40X2 PICAXE the only frequencies that you can get tht are controlled by the resonator are 8MHz and 32 MHz ? Is this correct ?
AB
28.July.2011
The manual says if you use an external resonator then it must be for a quarter of the desired operating frequency. Does this mean that the only way to get say 32MHz operation is with an 8MHz external resonator ? And with an 8MHz external resonator you can get 32 MHz operation, and [as well as neglecting frequencies for the external resonator is not absolutely required (ie, k31, k250, k500,m1, m2, m4, m8, m16)], the only other frequency control you can have is at 8MHZ with the external resonator described by nickab12 above ?
I am sorry this so clumsily phrased: with an 8MHz resonator and a 40X2 PICAXE the only frequencies that you can get tht are controlled by the resonator are 8MHz and 32 MHz ? Is this correct ?
AB
28.July.2011
Absolute_Beginner
Member
Thank you for confirming that, eclectic.
AB
28.July.2011
AB
28.July.2011