Hi All,

Some time back I had developed a simple Attendeance Management project.This uses RFID Reader and RF ID cards.

When a Card is swiped the µC(AT89C52),collects the data bits from the reader(26 bit wiegand).Assembles it and tries to match this id in the Master look up table(I2C based AT24c04).

The problem is that it is taking quite a bit of time(5-6 sec) to check the Id in the last location.Now how do we improve this...

1>Work around the routines to eliminate the not
required codes.
2>Use a higer speed I2C based serial Memory.(which 1 ?)
3>Implement Binary search alogorithm(I have used Linear search)
4>Use parallel memory(this will require to redesign the hardware)

Any other solutions...

Now RTC
I have used the PCF8563...as stated in the website we have followed "The high impedance inputs of the oscillator are sensitive to pick-up of
spikes, resulting in the clock running fast. The best preventive measure is
to shield the oscillator circuit and keep the connections to OSCI and
OSCO at an absolute minimum."

But the problem is that the time is getting slower and slower.Have anyone come across this problem while using this device or its better to use some other RTC?.Or am I doing something wrong.
I am very frequently reading the registers of the RTC(once every 1 millisec)...is this the cause for the problem.

If I have missed out anything... I will get with more details...

Rgds
Raj Shetgar