Unless you want an accurate 8Mhz clock.that pic has internal osc upto. 8mhz, no need for the Xtal.
From Eagle 7.2.0The Vdd value is shown at the output of the regulator. It is good practice to only show this value in one place (or, more specifically, to only have it defined in one place -- if you can define it in one place and have that value be used to show the value in multiple places, that's wonderful -- but few schematic capture packages allow that).
But can you cite a standard that supports your conclusion?The output of the regulator is connected to a symbol labeled Vdd.
The supply pin of the MCU is connected to an identical symbol labeled Vdd.
If two identical symbols that are both labeled the same thing are not the same node, then that is really poor.
Just where did I say that it was required or that it was per some standard? I said that it is "good practice" to only define things in one place, and it is.Without some standard, you might have been more accurate calling it your opinion.
That's a good question.What is your reason for the 2.2k and 3.3k resistors on the SD card pins?
I copied those resistors from an example schematic, i didn't really look into the purpose as it was the last thing i did before giong to bed for the night.That's a good question.
My guess is that it is a 5V to 3.3V voltage divider (which he almost certainly does NOT want).
The SD card is connected to port pins RC2 through RC5 and is operated in SPI mode. A card holder is used to physically make connections to card pins. The voltage at output pins of the microcontroller is too high and can damage the input circuitry of the SD card. A pair of potential divider resistors (using 2.2K and 3.3K resistors) is used to lower the microcontroller output voltages to a level acceptable by the SD card inputs. The SD card is powered using a 3.3V regulated supply, obtained using a MC33269DT-3.3.
by Duane Benson
by Aaron Carman
by Duane Benson
by Jake Hertz