[PIC] Micro-controller, generalities

[KhaledOsmani]

Hello,

What is the maximum voltage a PIC18F4520 can handle as input?
What is the maximum current a PIC18F4520 can handle also as input?

What is the minimum voltage a PIC18F4520 can handle as input?
What is the minimum current a PIC18F4520 can handle also as input? (analog inputs)

What is the maximum voltage a PIC18F4520 can deliver as output?
what is the maximum current a PIC18F4520 can deliver as output?

Using the internal analog to digital converter inside a PIC, how the ADC process is done?


what is a bootloader?

what is the maximum temperature the PIC can handle?


what does influence the speed of processing inside a PIC? what is its maximum speed?

 

[betwixt]

Lots of questions!

What is the maximum voltage a PIC18F4520 can handle as input?

Measured relative to VSS, no negative voltages are allowed and no voltage higher than VDD.

What is the maximum current a PIC18F4520 can handle also as input?

It noramlly draws almost no static current except for a tiny amount of leakage. If you force excessive voltage into the PIC input (not recommended), the protection circuits can handle maximum 20mA.

What is the minimum voltage a PIC18F4520 can handle as input?

Down to VSS. The threshold at which a pin is seen as logic low is typically 0.15*VDD for normal inputs and 0.2*VDD for schmitt inputs.

What is the minimum current a PIC18F4520 can handle also as input? (analog inputs)

Ideally none at all. the inputs are designed to draw zero static current, they are voltage driven not curent driven. Like all inputs, they have capacitance which has to be charged up and discharged so as frequency increases so dynamic current will flow. The amount depends on the frequency.

What is the maximum voltage a PIC18F4520 can deliver as output?

VDD at zero load current. It drops slightly as more current is drawn out of the pin.

what is the maximum current a PIC18F4520 can deliver as output?

Each pin can supply a maximum of 25mA to outside circuits and can sink 25mA from an outside source. There is a maximum limit for the combined current of all pins which is 200mA.

Using the internal analog to digital converter inside a PIC, how the ADC process is done?

It uses a 'successive approximation' technique. It first guesses at half the reference voltage and makes the MSB 1 if it is higher or 0 if it is lower. It then divides the difference between the half reference and the nearer of high reference and low reference and again compares to produce the next bit of the result. After doing this 10 times you have 10 bits of result. It is called successive approximation because at each of the 10 steps it approximates nearer to the actual value.

what is a bootloader?

A program you put inside the PIC to allow another program to be loaded. It comes from the concept of pulling yourself off the ground with your own boot laces. Usually it is a small program that configures the serial interface so you can load another program through the USART module.

what is the maximum temperature the PIC can handle?

-40C to +125C while operating and -65C to +150C when not powered up.

what does influence the speed of processing inside a PIC? what is its maximum speed?

The internal clock determines the speed. It can be produce by the PICs internal oscillator at approximately 4MHz maximum (RC mode but the frequency may be inaccurate and is temperature and VDD dependent, for very low cost applications only!) or by an external crystal or signal source. There are various dividers and multipliers inside the PIC that let you configure several frequencies from these. The maximum speed is 40MHZ.

Brian.

 

[bluelasers]

what is the maximum temperature the PIC can handle?

In storage: -65 to 150 Celsius
In operation: -40 to 125 Celsius

what is a bootloader?

A bootloader is a piece of software that runs below the app code. It runs on reset or device power up. The primary purpose is to allow a more customized way to upload new app code. Or possible select between two app codes loaded on to a device, using program memory partitions.

An example of a bootloader is arduino, which is a serial bootloader. On power up it checks pin, if pin is high then it loads the data off the serial port. This data overwrites the old app code. The means you can use a FTDI or serial port to program the micro-controller instead of a programer.

what does influence the speed of processing inside a PIC? what is its maximum speed?

This PIC is capable of 10MIPS or 10 million instructions per second. Since this is a PIC18 it means the max speed is 40MHz. The PIC18 architecture requires 4 clock cycles per instruction. Since the chip has an internal oscillator of 8MHz, with PLL (phase lock loop) you will only be able to reach a speed of 32MHz. The PLL is a 4 time multiplier. Enable it to make 32MHz or disable it to make 8MHz.

To get the full 40MHz or 10MIPS, you need an external 10MHz crystal using PLL or a 40MHz crystal without PLL. There are other ways also, so if you have a 20MHz crystal you could use 2 time pre-scaler to divide the speed to 10MHz then use PLL to get 40MHz.

Datasheet:
https://ww1.microchip.com/downloads/en/DeviceDoc/39631E.pdf

What is the maximum voltage a PIC18F4520 can handle as input?

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What is the minimum voltage a PIC18F4520 can handle as input?

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What is the maximum voltage a PIC18F4520 can deliver as output?

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what is the maximum current a PIC18F4520 can deliver as output?

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What is the minimum current a PIC18F4520 can handle also as input? (analog inputs)

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Using the internal analog to digital converter inside a PIC, how the ADC process is done?

I am not sure what you are asking. Page 225