I started working on DSP TMS320F28335, in pin configuration I have a set of five pins of ADC given as input of +5V to -5V, and other sset of pins ADC given as 0 to 3V. but how to proceed to give sinusoidal input to the DSP. Is it really possible to give AC signals to ADC converter
Hi...28335 is a DSP that requires every signal in the range 0 to 3 V...please make a shifter+scaler circuit using OPAMPS--- inverting amplifier+inverter-- this will scale any input sine wave to---a sine wave from 0 to 3 V..then give it to the pin
@Shashank Vyas Thanks for your answer, but I have come across a ppt, Can you have a look at ADC IN(-5V to +5V). In the pin configuration manual also they have given theses pins as ADC input of ADCINB3 to ADCINB6 with a ground. Which is given in the below given pdf at J33
1) TMS320F28335 requires every analog signal in 0 to 3 V range. I hope you have not manipulated the AREF or analog reference voltage which is zero volts
2) Use IC 741 or any OP-AMP---2 in number---use 100 K potentiometers--you need a DSO WITH PROPER ISOLATION TO VIEW THE WAVESHAPE
3) 1st stage-- summer --by inverting amplifier stage of OPAMP1--connect AC sine wave signals to pin 2 (the inverting pin) and a 3 V DC offset, all via pots ---> these 2 will be added---pin 3 will be grounded...pin 6 will be connected to pin2 via a fixed feedback resistor 100 K...pin 4 to bias +12 V..pin 7 to -12 V (or can be ground) --all grounds must be from same DC supply
4) 2nd stage--inverting amplifier---repeat same for pins 4 and 7 and 3 of next OPAMP but connect pin 6 of 1st one to pin 2 of second
5) check o/p of second stage---pin 6 with system ground--you must get a sine wave from 0 to 2.8/3 V on DSO---give only this to the ADC pin via buffer
the ratio of two 100k pot helps u in deciding the scale factor. And second stage acts as simple sign converter.
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