Need tip in Multiplexing 50pcs 7Segment Display

[marcasjr™]

Mga boss,ano po kaya magandang magandang gamiting IC para i control 50pcs 7segment display 5inch Height? gagamit po ako ng PIC168f77 as main controller,yun po kayang cocontrol sa bawat common ng 7segment ano kaya advice nyo? adviseble ba yung decade counter ?

Thanks!

[anthonydp]

try mo: 74HC595
one 595 per display, daisy-chained yung serial data.
yung 8-bit output ng 595 ang segment-data ng display.  yung common-connection ng display ay laging naka-connect sa ground (kung common-cathode) or V+ (kung common-anode).

[Kaizer03]

pede 74595, pero instead, you will control the common of the Seven Segment.. then the Data is from the MCU.. from here.. 7 74595 ang gagamitin mo..


not yet tested up to 50.. not so sure baka magflicker ito.. pero sabi nila up to 80pc seven segment eh kaya pa.. (tested up to 32 sa CD4094 na shift register, masmabilis ang 74595 IIRC kaya i think this will work) =)

[insomartin]

pede 74595, pero instead, you will control the common of the Seven Segment.. then the Data is from the MCU.. from here.. 7 74595 ang gagamitin mo..


not yet tested up to 50.. not so sure baka magflicker ito.. pero sabi nila up to 80pc seven segment eh kaya pa.. (tested up to 32 sa CD4094 na shift register, masmabilis ang 74595 IIRC kaya i think this will work) =)

kahit ilan pa yung seven segments sure ako hindi mag fliflicker during update. knowing na every second lang yung update and disabled yung output enable during shifting. latched naman yung 595 too.

[Kaizer03]

^

my idea will surely depend on the timings na gagawin mo.. kasi for every clock ng shift register(for seven segments' Common) plus the Data (a-dp) coming from MCU will limit this..(same with approach for some LED Matrix), and using this configuration, there is no way for you to use the latch feature of 595, since its output will be connected to 8 common of SSD and will have different data to display=)

not unless ang MCU na gagamitin mo eh can process fast much more the usual 8bit MCU

[labgruppen]

try mo: 74HC595
one 595 per display, daisy-chained yung serial data.
yung 8-bit output ng 595 ang segment-data ng display.  yung common-connection ng display ay laging naka-connect sa ground (kung common-cathode) or V+ (kung common-anode).

i concur with this one. in this scheme, there is no need to gate the 7segment . they are "on" at all times eliminating flicker. and since the 7segment displays are on all the time, mas maliwanag ang display nito as compared with multiplexing the 50 7segment displays which will be on only 1/50th of the time. tipid din ito sa gpio, needing only three to four gpio pins for all 50 7segment displays. just shift out the decoded 7segment display data and latch. then repeat at every refresh. and since there is no flicker, you can even refresh the display only when needed, that is only when there is a change in the data to be displayed.

and disadvantage lang ay medyo mataas ang parts count as compared sa multiplexed/scanned displays. (50ea 595 vs 7ea 595 for conventional scanned displays) but the brighter and flicker free display justifies the cost imho..

[Kaizer03]

^

agree, and also, masmadali ang programming nito.. and less process sa MCU =)

cost nga lang talaga ang masmatas at syempre lalaki ang board mo at mahirap(time consuming) magdesign ng PCB..

[insomartin]

74LS164 is a cheaper alternative din to 595's

[0b00000111]

o kaya per 74hc595, lagyan mo ng dalawang 74hc4511 para dalawang 7 seg per 595...... mahal kasi ang 74hc595 compred sa 4511... (btw, di na ako updated sa price ng 4511 ngayon hehehe, baka mali ang sinasabi ko cost-wise )

[marcasjr™]

I may use the 74hc595,since nakapagprogram na dati ng ganun pero led matrix.Ung pong transistor na kayang i handle 12v? ano suggestion nyo po? pang heavy duty po kac e2,24/7 ang operation.

Thanks...

[jaeger0825]

Hi, na-try ko lang gamitin is up to 12 Seven-segment (common anode) using combination of ULN2803 at UDN2981.