Mithun_K_Das
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flicker depends on multiplex frequency and multiplex rate.HC595 may be a better solution. but as it is 3 digits multiplexed I'm afraid if it flicker.
You showed a schematic with three displays and 4 digits per display.Who told you I'm doing only 3 displays? I said I'm just following that circuit. This never mean I'm doing only 3 displays.
Yes, you'll rather use 10 MHz SPI clock.With 100kHz SPI bus clock rate a small microcontroller is at 100 processing load.
Using the same lines as for SPI and digit mux might work under circumstances for three displays (with respective duty cycle loss). It's simply useless for a larger digit count.I'm following this circuit configuration. Using hardware SPI. Lets see what happen next...
Hi,
How do you decide to arrange them?
32 PCBs?
One possible solution:
32 PCBs
Each PCB:
* 3 x HC595 daisy chained.
* 3 inputs for the columns. They drive the column for the display as well as the OE of the HC595s.
(Only one OE active per time)
* Maybe you need a driver IC to drive the segments.
* Use a small MOSFET per column.
This makes multiplexing easy for the microcontroller. It just needs to activate the OEs sequentially.
Klaus
It's surely possible. Daisy-chained shift registers for segment data with sufficient high SPI data rate is a usual solution.So it is really not possible driving 32 pcs of 3 digit multiplexed 7segment?
I don't see a good chance for 10MHz with a load of 64 IC inputs paralleled ...and the cabling.Yes, you'll rather use 10 MHz SPI clock.
Not your way.So it is really not possible driving 32 pcs of 3 digit multiplexed 7segment?
The schematic for using a dedicated multiplexing display controller is as simple as yours....but doesn't need high data throughputusing single segment display for 32X3 pcs and shift register for each of the display will be a large circuit diagram as well as complex to make mistake too...
I wonder how you come to 96 pins.Even with this solution, it will require at least 96 pins to drive all the displays. Isn't it? So it will become a single MCU solution.
It depends. Nothing's been said yet about distributed design and cable length. You see however multi MHz SPI signals with the popular LED wall modules distributed over ribbon cables, utilizing just a few buffers for high fan-out signals.I don't see a good chance for 10MHz with a load of 64 IC inputs paralleled ...and the cabling.
I expect rather dirty signals.