Discussion in 'The Projects Forum' started by ching fong kee, Aug 4, 2010.
is it possible the PIC16F84A operate at 1V as minimum operating voltage?
No, the PIC16F84A has a minimum of 2 volt operating voltage...
but i test with my PIC
this is show the input pins when there is given to 1 volts, the LEDs that connected at output pins will be light up..
Are you asking then if you can use 1 volt to trigger an input to the pic or to run the pic off of 1 volt???
No, i means is
when the 1Volts to the input port pins , the PIC will treat its as digital '1'.
The recommended minimum operating voltage is 2V... Why are you only supplying it 1V?
Yes, that is correct, for TTL input logic high will be 2V or higher, but if using schmitt input buffer then .8/.9 V will be a logic high....
Because my sensor output will be connected to the input pins of my PIC.
When the output voltage of my sensor is reached 1Volts...the LED at output is turn on..
but the pins that i connect is RA0 but still is TTL right?
Yes RA0 is TTL, RA4 is a schmitt trigger input....
But since a logic low for TTL input buffer is less than or equal to .8 V then anything higher than .8 will be a logic 1.
Means the Logic high for all the input port will be the same as the RA4?
According to the datasheet no, but, in reality it should work since your input level is higher than a logic low, You may run into some issues later on if you still want to use RA0 as the input, I would switch the input to RA4 to minimize the risk of not getting the proper voltage to switch the input from 1 volt. Most TTL devices I have worked with in conjunction with a PIC, I have always made sure my logic high was atleast equal to 1.8V...
i see...thx a lot for guide ya..
i think i will switch my input to RA4..
BMorse, I think you have misread the datasheet. It states 0.8 Vdd is required, that means 80% of Vdd. If you supply it even the minimum 2V then 1.6V is the minimum guaranteed logic high.
hmmm...how come will like that..
it actually shows 1.2Volts is logic high
That's the minimum guaranteed rating. For example you might not get 1.2V as a logic high at 85°C or with certain batches of chips.
means is according to the circumference?
because i'm doing with the final report..
The operating voltage of PIC that i wrote is from 1V to 5.5V
i afraid that is unacceptable..
The RATED operating range is 2V to 5.5V. This is the range Microchip guarantee the chip will work in its full temperature range, at maximum speed and with all the chips that come out of the factory.
I have seen PIC16F series chips run on a 1.5V battery at 32 KHz, but there's no guarantee whatsoever from Microchip or me that they will work at 4 MHz or 85°C. I have also seen them work on a 9V battery for a few minutes before blowing smoke (literally), and I run the occasional prototype at 6V with few / no problems.
That is why I suggested to make sure to get atleast 1.8V for a logic high... the 0.8 is a logic low, not High.
Operating Voltage is not the same as the logic level inputs... Operating Voltage means the power you are using to power the whole circuit i.e. 2 to 5.5 Volts....