--BawA--
Advanced Member level 1
- Joined
- Nov 28, 2012
- Messages
- 479
- Helped
- 43
- Reputation
- 86
- Reaction score
- 42
- Trophy points
- 1,318
- Location
- Noida, INDIA
- Activity points
- 4,926
I am using DSPIC33FJ32MC202bigdogguru said:What is the specific model of dsPIC33 to which you are referring?
If i use internal FRC whose nominal frequency is 7.37mhz range .and gives its output to onchip PLL (VCO range is 0.8 to 8mhz) followed by a prescaler and postscaler ,will it be possible to achieve a Fcy of 20mhz??
how to set internal oscillator frequency of 20mhz in dspic33 series MCU?
If i use internal FRC whose nominal frequency is 7.37mhz range .and gives its output to onchip PLL (VCO range is 0.8 to 8mhz) followed by a prescaler and postscaler ,will it be possible to achieve a Fcy of 20mhz??
Sorry by mistake i have written Fcy ,,it should be Fosc only.If i use internal FRC whose nominal frequency is 7.37mhz range .and gives its output to onchip PLL (VCO range is 0.8 to 8mhz) followed by a prescaler and postscaler ,will it be possible to achieve a Fcy of 20mhz??
if in case i have to use external crystal oscillator of 20mhz , do i have to set any register bit for that, or simply just connect the oscillator to the MCU ,it will automatic switch to external oscillator rather than using internal one.?
For example, suppose a 10 MHz crystal is being used
with the selected oscillator mode of XT with PLL.
Fosc = Fin*(M/(N1*N2))
• If PLLPRE<4:0> = 0, then N1 = 2. This yields a
VCO input of 10/2 = 5 MHz, which is within the
acceptable range of 0.8-8 MHz.
• If PLLDIV<8:0> = 0x1E, then
M = 32. This yields a VCO output of 5 x 32 = 160
MHz, which is within the 100-200 MHz ranged
needed.
• If PLLPOST<1:0> = 0, then N2 = 2. This provides
a Fosc of 160/2 = 80 MHz. The resultant device
operating speed is 80/2 = 40 MIPS.
Fosc = 80MHz = 10MHz * (32/(2*2))
bigdogguru said:are you breadboarding this design?
also plz take a look on my other post too, https://www.edaboard.com/threads/305547/#post1307611
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?