Constraints

Hi, Dinesh… Janardhan here.. Actually I’m doing a prototype for Digital Fuel Indicator fitting, Light Combat Aircraft (LCA, Tajes). Here I’m using a voltage controlled Oscillator of calculating the amount of fuel in the centralized fuel tank which is a part of my internal architecture of out project. Coming to the main programming part, I use square wave whose amplitude will be less than 2v n give this as a input for any I/O port, from P1.0 to P1.7. Micro-controller 89C51 should first be programmed to find the frequency of the variable incoming square wave signal and convert this frequency to times constraints. Ie., t = 1/f. Then this time constant is multiplied with the constant and the result should be assed to LCD display driver through output port.

Fuel Content (Kg) Existing 425 400 360 340 300 260 220 180 140 100 80 60 35 20 5

Modified 430 407 385 359 320 300 272 208 140 89 66 54 30 13 0

Output which be displayed on the LCD,

F1A Probe Output (Time period of the frequency output in µ sec) 189.3 ~(5,000 Hz) 184.6 178.2 175.2 168.9 161.7 153.5 144.1 134.0 124.1 119.4 115.2 111.2 109.5 105.0 ~(10,000 Hz) Input frequency

Constraints to be satisfied are, 1. The converted freq to time should be a part of the 89C51 program only. 2. Look up table shouldn’t be applied, 3. Ie, the program should work on real time constraints. 4. Any port pin of P1 can be used here. 5. Incoming freq is varied only 5k to 10k Hz only. 6. On getting the time in micro secs, corresponding modified value is to be outputted as shown in the above table.

7. P0 or P2 can be used as output port to connect LCD display drivers. 8. LCD used here is 1x 8 only. 9. The Modified table is the expected output, which is to be displayed on the LCD display. 10. Program should contain a code for driving LCD also, within. Since the incoming freq is halted for few seconds before changing the freq, i used a timer for 1se n a counter to count the incoming freq. but, I was not able to get the clear picture, so worried. Tried to convert incoming freq to binary data n then process this binary data, but that became more n more complex then I expected. So, I tried n called Karthik n got your number. I’ll be happy to receive the code from you. Thanks a Ton.. Hard ware part is doing good n now should test with the program in 89C51.