If clk freq is reduced, display blinks...

[mandar_mahajan]

Hi all, I am using P89LPC938 with internal clock freq of 7.37MHz.
& interfacing a bare 4 backplane * 13 segment display with it.

My aim is to reduce the current consumption for prolong use of the battery.
So i have used the DIVM reg of it. Using this the currents drops by 2mA(DIVM = 1), 4mA (when DIVM = 4). But the display starts blinking...
I dont know why this is happening. I am displaying my adc value in while(1)
after every 300msec.

Any notes to improve my understanding would be of great help to me.
Thanks!

 

[FvM]

Apparently you have to adjust the display mux frequency. The answer is in your code.

 

[mandar_mahajan]

Hello FVM,
I do not get ur point. I have change the timer reload values accordingly.

 

[snafflekid]

Each digit of your display is connected to a single display driver for a brief time period through a signal multiplexer. A signal multiplexer connects each digit to the display driver sequentially which is usually faster than visual perception. When you lowered you clock frequency, you slowed the speed that the multiplexer cycles to each digit and you see the blinking.

 

[mandar_mahajan]

Yes this is the problem i am facing.
What i have done as a solution is, put some filters to display the adc contents.
this results in blink only when the no is changing, else it remains steady.

Any other solution??

Regards
mandar