DSPIC33FJ128GP706A-I/MR Microchip Technology, DSPIC33FJ128GP706A-I/MR Datasheet - Page 88

• Manufacturer Part Number: DSPIC33FJ128GP706A-I/MR
• Description: IC DSPIC MCU/DSP 128K 64-QFN
• Manufacturer: Microchip Technology
• Series: dsPIC™ 33Fr

Specifications of DSPIC33FJ128GP706A-I/MR

• Core Processor: dsPIC
• Core Size: 16-Bit
• Speed: 40 MIPs
• Connectivity: CAN, I²C, IrDA, LIN, SPI, UART/USART
• Peripherals: AC'97, Brown-out Detect/Reset, DMA, I²S, POR, PWM, WDT
• Number Of I /o: 53
• Program Memory Size: 128KB (128K x 8)
• Program Memory Type: FLASH
• Ram Size: 16K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 3.6 V
• Data Converters: A/D 18x10b/12b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VFQFN, Exposed Pad
• Product: DSCs
• Processor Series: DSPIC33F
• Core: dsPIC
• 3rd Party Development Tools: 52713-733, 52714-737, 53276-922, EWDSPIC
• Development Tools By Supplier: PG164130, DV164035, DV244005, DV164005, PG164120, DM240001, DV164033
• Core Frequency: 40MHz
• Core Supply Voltage: 3.3V
• Embedded Interface Type: I2C, SPI, UART
• No. Of I/o's: 53
• Flash Memory Size: 128KB
• Supply Voltage Range: 3V To 3.6V
• Rohs Compliant: No
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

MCP3909 / dsPIC33F 3-Phase Energy Meter Reference Design
DS51723A-page 88
We get:
EQUATION C-49:
EQUATION C-50:
As Δf << f, from Equation C-49 and C-50, we have:
EQUATION C-51:
Therefore,
EQUATION C-52:
Assuming that the signal's initial phase angle measured in the 1st cycle is
the N-th is
frequency is:
EQUATION C-53:
ϕ
N
, then the difference between actual frequency and the assumed
u
a
Δ
u
f
=
ϕ
b
≈
u
2u
---------- -
1
=
⎧
⎪
⎪
⎪
⎨
⎪
⎪
⎪
⎩
≈
T
(
c1
ϕ
(
2u
---------- -
⎧
⎪
⎪
⎪
⎪
⎪ ⎪
⎨
⎪
⎪
⎪
⎪
⎪
⎪
⎩
ϕ
N
tg
(
T
N
tg
⋅
ϕ
c1
−
(
------------------------------------------------------------------------ -
−
tg
−
N
−
f
1
2
u
---- -
u
1
2
ϕ
(
2
⋅
π
ϕ
+
(
π
a
b
−
−
u
π
u
1
3
1
f
------------------------------------------------------- -
u
u
π
1
2
2
π
a
b
⋅
≈
(
ϕ
+
⋅
Δ
⋅
a
b
⋅
−
u
u
N
)
( ,
N
1
N
cos
( ,
)
2
f
--------------------- -
cos
π
π
sin
a
b
+
)
2
)
u
+
π
u
( ),
⋅
π
b
2
⋅
⋅
⋅
b
π
)
f
(
π
)
(
sin
(
(
(
=
⋅
u
ϕ
=
( ,
ϕ
⋅
2f
2f
( ,
ϕ
( ,
f
b
, 0
u
f
u1
u1
, 0
u1
u
ϕ
(
>
( ,
b
+
+
u
( ,
b
ϕ
)
u
N
)
ϕ
)
, 0
a
>
ϕ
u1
<
a
Δ
⋅
Δ
N
−
>
u
, 0
N
sin
<
, 0
f
f
)
ϕ
a
)
)
−
) 0
u
−
) 0
u
⋅
1
⋅
⋅
>
ϕ
a
⎛
⎝
a
ϕ
sin
Δ
Δ
1
πΔ
-------- -
<
) 0
<
1
>
f
f
<
f
π
) 0
>
⎛
⎝
) 0
f
)
−
πΔ
-------- -
⎞
⎠
π
π
f
)
© 2009 Microchip Technology Inc.
)
f
⎞
⎠
ϕ
1
and in