Question regarding led matrix.

[maniac84]

Hi guys,

I'm using a MBI5026 drivers to drive the column data for my 64x16 led matrix.
My main program on AT89S52 is just doing shifting of the column bits. May I know if I shift the bit one by one, wil the old bits still remain there?

 

[BabaYaga]

Looking at the timing timing diagram and the truth table, the old bits will not remain their.
Moreover you can see that the ic uses SPI interface so it has got SDO, where one bit enters the shift register then the other end bit is shifted out on SDO which means that the old bits will not remain their.
whenever the LE goes low the input data bits are latched.

you can try to view the output on a oscilloscope by sending a pattern of 10101010 or 01010101.

Hope this helps.

 

[maniac84]

Looking at the timing timing diagram and the truth table, the old bits will not remain their.
Moreover you can see that the ic uses SPI interface so it has got SDO, where one bit enters the shift register then the other end bit is shifted out on SDO which means that the old bits will not remain their.
whenever the LE goes low the input data bits are latched.

you can try to view the output on a oscilloscope by sending a pattern of 10101010 or 01010101.

Hope this helps.

Thanks for the info.
Is the MBI5026 the same with TPIC6C595 in terms of shifting the data? Can the old data remain in TPIC6C595?

 

[BabaYaga]

TPIC6C595 is a shift register, i'm not sure about the MBI5026 since the datasheet is tricky to understand esp the truth table.
But i can say that TPIC6C595 cannot hold the old data as it takes 8-bit data serially at a time, once the whole data is written in the shift register then CLR has to go high and then the data is transferred to the output buffer and then clr has to go low and soon as it goes low the shift register is cleared. hence we loose the old data.

Can you please tell me why are you so specific about old data?

- - - Updated - - -

How are you transferring bit by bit data?
what signals are you using?

- - - Updated - - -

How are you transferring bit by bit data?
what signals are you using?

 

[wavelet1208]

About matrix display,i fond some data(schematic and datasheet) at here

when MBI5026 shift in one bit data,at same time the old bit is shifted out.you said your display width is 64,so you can shift 64bit data in first,and latch,enable output.

you can see MBI5026 timing.