anyone out there..pls help me out!.. im having problems writing a program using uVision2 for a 8052 developement kit. problem no.1: I have a Waveform of unknown freq from a swipe card which has TTL voltage of 0 and 5v. we need to design a program using C to count the time between the very 1st 2 high voltage (1st 2 high V) problem no.2: Next we hav to decode the waveform using a table. Basically its a Magnetic Swipecard we hav to decode, track 2 (eg 411557, 5bits per character) half the program has been written so far but we can;t seem to output it to the LCD display... HELP ME ANYONE PLEASE!!!... Desperate. ps: any qns, pls feel free to email me arelius@visto.com
Hi Erik, well, just looked it up again... you can sure use the internal clock too. I just remembered an old application of mine, where I used a variable external clock to meassure the length of something moving through a light barrier. The external clock was relative to the speed of the movement. So I was not sure, if the c51 would be able to use the internal clock for the capture mode... just too long ago :)) Take care Sven
Sven, This is the first time, ever, I have heard of clocking a timer with an external frequency. Please clarify your reasons for nut running T2 as a timer and using EX0 or EX1 to stop it. I am very curious as to why. Erik
You should make use of the features of the Timer 2. You can feed the T2 input (Port 1) with a clock signal of a certain frequency... (maybe 100kHz) and use the T2EX input for the signal to be meassured. A 0->1 transition of it will cause an interrupt and the counter content will be captured in a certain 16-bit register. This way, you can meassure the period of the signal with the accuracy of your 100kHz clock. The Timer 2 has to be configured in capture mode. The operation of it is described pretty well in the datasheet of your processor. Take care Sven
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