![]() ![]() The ADC will have offset, gain errors, differential nonlinearity, thermal drift of all those parameters, circuit thermal noise, reference noise, power supply noise, digital feedthrough, analog crosstalk, sampling artifacts, charge droop, ground bounce, to name a few of the possible sources of internal errors in the ADC circuit. But there are a number of degrading factors to that response, both internal and external to the chip, that renders useless the computing of lookup tables with the ideal values. The ideal response is exactly what ric told you. Gettyah, about the conversion formula: A/D converters are inherently non-ideal circuits. Being inside the AMR will save a huge characterization cost, because the manufacturer already did the testing, and reported in the AMR tables. But this requires extra knowledge and extra characterization, to validate your design. Of course, there are occasions when you do design some circuit that takes advantage of every little detail of the chip, and allow it to go beyond the limits. When analog performance is important, you have to make sure that no pin (analog or digital) is allowed above VDD, or you will have offset and gain errors in the analog section. If an ESD event happens when a pin is flooding the substrate diodes with current, the ESD could cause more damage than if the diodes were not conducting. This extra stress will have 2 major effects: the analog performance (noise and accuracy) will suffer and the chip ESD protection is compromised. When a substrate diode conducts, it generates stray currents through the substrate and increased current density on several areas of the chip. This does not imply that overvoltage currents below 20mA are considered legal. The AMR state that at 20mA you will likely fuse the internal chip connections due to excess heat. The so called 'protection' diodes will conduct, making the current to sink through the VDD pin. That said, let's see what happens when you let a voltage in a pin to exceed VDD. The AMR is a statement from the factory telling the user that if he or she allows the part to be exercised outside those limits, all bets are off. Anybody that is designing a product based on the chip must design inside the AMR limits, if the product is to hit anywhere outside his or her lab. You may apply higher voltages to any I/O-pin, but you have always to consider the current, which is running into the pic. Its written in C using MikroC.I do not agree with this statement in general. ![]() #Picconvert wiring codeFor reference, here is my code for the PIC. This does not work, however, and I’m totally lost. In the circuit I constructed, I first tested to see if the LEDs would work with 3 1.5 Volt AA batteries and they worked fine so I figured resisters wouldn’t be necessary. I’ve bought 3 LEDs (3.3 Volts each), some pushbuttons, and wire and I’ve constructed the following circuit: The problem is I have no idea where to start. Working with the experimentation board is great but I want to move this to an actual circuit. PINs RA0 and RA2 are the inputs for the trigger and reset pushbuttons respectively while pins RB0, RB1, and RB2 are the output pins for the LEDs. I’ve been testing this on a Velleman’s K8048 PIC Programmer/ Experimentation board. ![]() I’m completely new to the world of PIC Microcontrollers and electrical engineering so please go easyĪnyway, I managed to program my PIC 16f627 to turn on three LEDs when push button (trigger button) is pressed and start a shut down sequence (basically each LED toggles off one after another with a 5 second delay in between) when another pushbutton is pressed (reset button). Online Schematic and Circuit Diagram Tool.Microcontrollers and other Microchip devices Search tool.Find debuggers, programmers, compilers, adapters, socket modules and other accessories for your product. #Picconvert wiring pdf
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