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Multiplication Help Wanted!!

Dear Keil Community,

I have built a digital thermomter using AT89C52. I have to display the temp on a LCD. The ADC is 10 bits and after coversion routines, i get the hex equivalent of temperature as 368. Now 368 is to be diplayed as 3.406 on LCD. .406 is got as follows:
6/16 = 0.375
8/256= 0.031
Adding 0.375 + 0.031, we get 0.406

Please guide me as to how to do this conversion in C51.
Thanks for all the Help.

Parents

0 Karl Hamsher over 20 years ago in reply to Mark H

unsigned short rawTemp; /* 10bit ADC value */
float actualTemp;

actualTemp = (rawTemp & 0xf00) >> 8; /* scale the units */
actualTemp += ((rawTemp & 0xf0) >> 4)/16 /* scale the 1/16's */
actualTemp += (rawTemp & 0x0f)/256; /* scale the 1/256's */

Or simply:

unsigned short rawTemp; /* 10bit ADC value */
float actualTemp;

actualTemp = rawTemp / 256.0;

Reply

0 Karl Hamsher over 20 years ago in reply to Mark H

unsigned short rawTemp; /* 10bit ADC value */
float actualTemp;

actualTemp = (rawTemp & 0xf00) >> 8; /* scale the units */
actualTemp += ((rawTemp & 0xf0) >> 4)/16 /* scale the 1/16's */
actualTemp += (rawTemp & 0x0f)/256; /* scale the 1/256's */

Or simply:

unsigned short rawTemp; /* 10bit ADC value */
float actualTemp;

actualTemp = rawTemp / 256.0;

Children

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