pic24hj12gp202 Microchip Technology Inc., pic24hj12gp202 Datasheet - Page 81

• Manufacturer Part Number: pic24hj12gp202
• Description: High-performance, 16-bit Digital Signal Controllers
• Manufacturer: Microchip Technology Inc.

For a primary oscillator or FRC oscillator, output ‘F
the PLL output ‘F
EQUATION 7-2:
For example, suppose a 10 MHz crystal is being used,
with “XT with PLL” being the selected oscillator mode.
• If PLLPRE<4:0> = 0, then N1 = 2. This yields a
FIGURE 7-2:
TABLE 7-1:
© 2007 Microchip Technology Inc.
Fast RC Oscillator with Divide-by-N
(FRCDIVN)
Fast RC Oscillator with Divide-by-16
(FRCDIV16)
Low-Power RC Oscillator (LPRC)
Secondary (Timer1) Oscillator (SOSC)
Primary Oscillator (HS) with PLL
(HSPLL)
Primary Oscillator (XT) with PLL
(XTPLL)
Primary Oscillator (EC) with PLL
(ECPLL)
Primary Oscillator (HS)
Primary Oscillator (XT)
Primary Oscillator (EC)
Fast RC Oscillator with PLL (FRCPLL)
Fast RC Oscillator (FRC)
Note 1:
Source (Crystal, External Clock
or Internal RC)
VCO input of 10/2 = 5 MHz, which is within the
acceptable range of 0.8-8 MHz.
2:
Oscillator Mode
OSC2 pin function is determined by the OSCIOFNC Configuration bit.
This is the default oscillator mode for an unprogrammed (erased) device.
F
OSC
OSC
CONFIGURATION BIT VALUES FOR CLOCK SELECTION
= F
’ is given by:
F
PIC24HJ12GP201/202 PLL BLOCK DIAGRAM
IN
OSC
*
(
N1*N2
CALCULATION
M
)
Divide by
PLLPRE
2-33
Oscillator Source
0.8-8.0 MHz
Secondary
Primary
Primary
Primary
Primary
Primary
Primary
Internal
Internal
Internal
Internal
Internal
Here
Preliminary
IN
’,
X
PIC24HJ12GP201/202
• If PLLDIV<8:0> = 0x1E, then M = 32. This yields a
• If PLLPOST<1:0> = 0, then N2 = 2. This provides
EQUATION 7-3:
VCO output of 5 x 32 = 160 MHz, which is within
the 100-200 MHz ranged needed.
a Fosc of 160/2 = 80 MHz. The resultant device
operating speed is 80/2 = 40 MIPS.
POSCMD<1:0>
Divide by
F
PLLDIV
CY
2-513
VCO
=
xx
xx
xx
xx
10
01
00
10
01
00
xx
xx
F
100-200 MHz
2
OSC
Here
=
2
1
(
10000000*32
PLLPOST
XT WITH PLL MODE
EXAMPLE
Divide by
2, 4, 8
2*2
FNOSC<2:0>
111
110
101
100
011
011
011
010
010
010
001
000
)
12.5-80 MHz
= 40 MIPS
DS70282B-page 79
Here
Note
1, 2
F
1
1
1
1
1
1
1
OSC