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better way is to use latch and no multiplaxing. directly use latch and use mcu behind it
Every logic family is characterized by different output drive current .. For example, 74ACT logic family can drive +/- 24mA of IOH and IOL .. Any output current above ≈5mA can directly drive an led (via a resistor) .. You have to google for I of your latch .. Rgds, IanP :D
Hi. How are you going to read the data into the latch. One row at a time, or just having some external hardware/circuitry that is synced to the counter?
Was just thinking... Is it not possible to cascade shift registers with a clock and data line... And then use 1 enable line to latch the clocked data to the output. In this way you can have as many outputs as you like on 3 pins. Number of outputs are the number of clock cycles. Think I will try this also...
Hello. I need to drive five led bars, that have 20 led each. I think to do use latches for multiplex the 5 bar, and latch to store the level for each bar(0~20). Any ideas to drive (digitally, not analog with 1496 series)this quantity of leds with a minimun of lines? PicsOne
Hi, The LCD data sheet specifies a supply voltage of Vled = 2.1V and a supply current Iled = 40mA. (The led backlight consists of 4 led chips) I would be grateful for any feedback on the following proposed solution: I am using an output from a 74LV573 latch. I am using a voltage divider network (...)
Hai, everyone i try to drive the port 82C55 via pararel port, but ihave problem with latch that mention on schematics, i attach all port 8255 wih sourcing led and i inisialize the port tobe output. when i running program the problem arise 1. led on port A that should ligh on it's following this condition off-on-off again (some kind this (...)
You can use this latch IC 74HC273. It has 8 D-FlipFlops.
I'm trying to run a matrix of 16x5 of regular red led's using the TLC5920 and I was wondering if anyone had a sample working schematic that I could use as a reference. I downloaded the pdf but it was sparse on details for how exactly to set it up. I'm using a PIC18F2420 to run it and have spi(in,out,clk), latch, blank, csel(0-2), and +5V and GND
hi I'm working on TMS320F2812, a 32-bit DSP. I need to interface an a 8X1 led with my Processor through the GPIO's of the processor. The GPIO's are connected to the led's through a 74HC273 D-latch. Can anyone give me pointers on how I must go about the same ?? I have a couple of doubts : 1. My GPIO pins are wired to the D0 to D7 (...)
IT HAS BEEN EXPERIENCED THAT CONNECTING ledS IN PARALLEL WILL CAUSE ALL ledS NOT TO TURN ON WITH EQUAL INTENSITY OR NOT EVEN TURN ON This will happen if I am connecting led to a common driving point. If I use a D latch for switching the leds, there will be 7 separate driving points. So it is similar (...)
Thanks for the awnser Here is a sample code ( Bascom) The Anodes of the leds are at VCC, the cathodes to the shift registers. Not multiplexed. Do Outstring = ">>>>>>>>" Gosub Processoutstring 'This procedure transform the message in a bit array For A = 1 To Outarraycounter ' Arraycounter is the lenght of array
Hi sidy50, Can I latch the output of pwm controller? I want to use ADG508 as a analog switch. is it a good solution for high speed switching of pwm? when I design a optimum circuit for this I will use it at CPLD. Hamed.
good day EDA fellows.. I had this one question.. I am doing a charge pump for the led. I have two powerPMOS. How can I check any forward bias junctions in the circuit? Something any relation with latch-up. Can I obtain these information in the .lis file? Thank you for anyone who can share his ideas and experience.
I'm doing some experiments with 40x7 led matrix display and I'm trying to built effect where dots are switch on randomly to form letters. Say, first column has to be 0b11111110. First pass column looks like 0b00000000 Second pass 0b00001010 Third pass 0b10001110 forth pass 0b10111110 fifth pass 0b11111110 Every column must have own rando
Circuit to count led pulses and latch on right number Should be quite simple.... I think...? Say cct 'sees' 24 blinks - then no more (ie, too many means no_good) I'd prefer it f this can be done without a microcontroller - ie. a simple fixed cct (no need to be able change the correct count once built). If the right number - then (...)
I need to create a circuit that flashes a green + red led, as well as sounds a buzzer a certain number of times when a switch is activated. Here is how it should work: 1) a reed switch activates and the GREEN led will flash X number of times, along with a buzzer alarm. 2) a 2nd reed switch activates and the RED led will flash X number of (...)
Thanks a lot, I will check the enable and latch carefully.
hi all, i am currently working on a project which is about led driver for electric torch, it's very common that we use battery supply in this application, and in my project i chose to use a 2A chargeable battery... but when i am designing the feedback for the driver, i use 3V- 0 range for all the components which are amplifiers / comparators,
I'm trying to use my wireless doorbell to switch off my water pump. The problem is how to use the receiver signal to latch a relay. Search the net but no clear solution found ! I've driven led from a speaker wire with transistor (doorbell receiver circuit) but don't know how to use this signal to latch a relay. I'm planning to use 6v (...)
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
Hello, I have to interface around 120 led's to PIC18F4520. I am planning to do it with latch IC 74HCT574. But it increases number of latch IC's. As per the datasheet the maximum current sourced and sunk by all ports of micro controller is 200mA. Is it enough to drive all the led's? Please suggest. Thanks, paddy
Hi You should use three outputs of micro. Data, Clock, Strobe Set clock to zero Wait Set data (zero or one) Wait Set clock to one Repeat above pseudo code eight times then Set strobe to one I had the following C code with inline assembly from 10 years ago when I was a student. I used 4094 to extend PC parallel port. You need to call ON() or OFF
'LS373 is a 'transparent' latch. This means that while your Enable is active (and in your circuit it is always active - pin 11 high) then the data presented to an input will always immediately get reflected to the output. As long as output is enabled (which it is - pin 1 is Low) For this latch to hold data, you must do the following
Worked on PIC micrcontroller not on Texas but will give general idea ,.Might have to select the Oscillator internal or external , Then decide port you will be using , if the port has mulitple functions then try to disable them first , select the ports as output by setting the direction as ouptut ...generally in pic TRIS is used to select directio
I can see from the datasheet that this is a shift register so the fundamental question I have is are you latching the output? You are seeing the data out so when know that you are shifting it in but I am not sure that you are latching it when it has all been shifted in place.
Hello! Does anyone have any project example on design of HW and SW of led moving display. I'd like to show messages and if is possible with multiled. Anything would help. Regards!
May I ask this very stupid qustion :smile:? I wonder why they don't even include a generic model of led in their diode library. ee_freak
I need to use an led in such a way that the led will lit when the voltage across the led is sufficient to lit it but the led will remain lit even after the voltage across it drops to zero. Is there any simplest way to do that?
How do you maesure the output from a red led
Do you know UAA180, is a led bar driver for 12 segments, ideal to build Vu-meters. I need the spice model for these component. thanks..
Hi, I want to build a circuit that when i start it the led will stay off about 30 sec. then it wil illuminate 1 min. and then it will go will lock the start button i mean when i give another pulse it will not accept the second one.I tried to build it with 556 but nonsense. Please hellllpppp!!!
i want to know why people use memory in design rather than register or latch. less area or speed ? thanks
Hi If anybody know any hardware details about the moving pannel display for led matrix, whcih displays graphics also. Is there is any character map generator IC? pl give the implementation details how can we address each led individually. I will be using 89C51 for the implementation of the project Every suggestions are welc
i need datasheet or any info for HD-M514RD led display used in 1Ghz frequency counter
Hello, i have to make a you a question, if you tend to mux 50 bytes per second, like Year said, you probably not be able to view characters with an useful brightness. I should make this thing ,instead: Make an static driver for one character map, i mean 5 bytes, so i recomend you to use a shit register with latched buffered outputs to dri
I'm looking for a big led moving message display schematic diagram or ideas. I want to use about 256x256 leds on my display and i want to make an animation on it. I want to use discret component and pic processor not expensive proicessors. I made a little (32x32) one with pic16f84 and many eproms memory for the program for display but for this b
Does seven segment led spice model exist? Thanks!
I need to drive an array of 100 (10X10) Blue leds and 100 (10X10) Green leds at the same time and the leds will be lit until the power is turned off. All the leds are from Nichia (NSPB300 & NSPG510). I need a driver circuit for this. Thanks in advance!
Does anyone has experience with ASIC design with latch and two phase clock? I though it may save area using latches. The two phase clock scheme can handle the timing problem with latch. What I don't know is whether it can be employed in the ASIC design flow using Synopsys tools. Would anyone like to comment on the timing check and DFT of (...)
led Matrix (france)
A clock design pic16c54 for led displays and switch inputs schema+asm
Multiplex led Drive ,4x4 keypad sampling
hello, i need a help to understand how to calculate the forward current of an infrared led...(the limits) ex. led55C continuous forward current = 100mA forward current @ 1uS / 200Hz = 10A but, what duty cycle shoud i use if i want less than 10A? ex. if i want 200mA @ 200Hz how many uS turned on shoud be the led limit ???? im (...)
The technical information is here The led must go on if i go over the sensor Please help me with a schematic
Would like to share the experience / information regarding 1. RGB oval led selection 2. led drivers 3. Control electronics 4. Software
Hi Anyone have the experiment or reference about color led Drive IC . thanks
Hi Friends I need information about how i make a white led pwm driver any idea on that, regards Fragrance
Experimenting with the MAX6950 and the MAX6951 SPI led Display Drivers from a PC