I am doing a project based on physical parameter I am using adc 7135 for conversion. Please any one help me providing the assembly level code for drive the adc
The ICL7135 is an integrated ADC with multiplexed BCD & digit select drive to a numeric display. That is not really a microprocessor interface device, although it can be read into μP inputs. It appears the strobe pulses must be read as an indicator that, after the A-D conversion the 7135 output Digit code and BCD value of digit are valid for reading-in. Since the ADC takes >20000 clock cycles per reading, an interrupt driven μP routine seems sensible - it would appear 2 x 8 bit inputs [including data like over-range] should be read by μP when strobe occurs.
Doing internet search finds you are not the only one using 7135 e.g.
Surely, the point of the project is that you understand how the 7135 outputs data & design your own interface software - not cribbing other people's work?
I think you need to carefully read "Strobe" section in ICL7135 data sheet & figure 4. Over 1000 counts, each digit is output for 200 counts each; D5 then D4 etc
I cannot see how the code referenced is reading the 5 BCD digits into an array of RAM in succession after BUSY changes state. You need to read the BCD at the middle of each digit pulse e.g. wait 100 counts after "not busy" for the first digit, then 200 counts for the following 4 digits. You must use μP timer counts of equivalent time to 100 & 200 of 7135 counts, allowing for their clock periods.
Interfacing ADC7135 With 89S52
Re: Interfacing ADC7135 With 89S52
