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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
i would suggest u use C or picbasic pro for ur project... so u can left those redundant stuff to b done by the compiler n u can concentrate on ur algorithm... mostly this type of chift register is quite simple to use... mostly is clk, strobe, enable, data... as it name imply, the clk is the shifting clk..... strobe is like latch when u assert
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 (...)
a) are the above signals(just interfacing) enough(optimized) for the subjected application except VDD and GND. - You need to drive RCLK (Register clock) pin as well to transfer content of shift register to output latch. You need rising edge to do that. b) Is there any requirement for RCK clock pin?? -look under a c) how should i conne
better way is to use latch and no multiplaxing. directly use latch and use mcu behind it
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
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
Both options have advantages and disadvantages. In parallel connection (without latch IC): you will save the hardware but the programming will be little bit complex, as you need to refresh each display faster so as to avoid flickering In serial connection (using latch ICs): hardware will increase programming will be easier, as you need t
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.
There is no such thing as C++ for PIC uC, and in your code that you posted, I can't see any mention of 595 shift register. For 595's you only need 3 pins: one for serial data, one for serial clock, and one for strobe (assuming that you keep your 595's constantly enabled). ---------- Post added at 20:15 ---------- Previous
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 (...)
In the following code void sen_data(unsigned char c) { unsigned char i,k; latch =0; SCK = 0; for(i=0;i<8;i++) { DI = ( C & 0x80)?1:0; SCK = 1; c = c << 1; SCK = 0; } latch = 1; DI = ( C & 0x80)?1:0; what does this line do .. can u explain please and c = c << 1; will shift data from msb .... i suppose we have to shift data from lsb to M
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?
Thanks a lot, I will check the enable and latch carefully.
Dear All, I have 4 shift registers for 32 columns and 8 rows are directly connected via Port A of Microcontroller. I have to activate each row one by one and feed all the 32 columns data and then latch them. The problem is: 1) how to send 32 bits for 32 columns one bye one, and 2) How to create scrolling effect from right to left...? e.g.
You have generated many latches in this design, by incompletely specifying the state of several registers. Registers such as led and solenoid are not initialized, and are described in only a few states. This incomplete specification leads to generation of latches, which undesireable for most designs. Hence the warning regarding (...)
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
Look at the datasheet!!! EXAMPLE 12-1: INITIALIZING PORTA BANKSEL PORTA ; CLRF PORTA ;Init PORTA BANKSEL LATA ;Data latch CLRF LATA ; BANKSEL ANSELA ; CLRF ANSELA ;digital I/O BANKSEL TRISA ; MOVLW 0Ch ;Set RA<3:2> as inputs MOVWF TRISA ;and set RA<7:4,1:0> ;as outputs Clear LATA and ANSEL
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
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heh ppl, am assigned this project that has this user using dip=switch input a 4-bit binary into this 'game'. this is to be compared to another dip-switch's value. 4 wrongs and a red led will light. its its right in >4 tries, green led lights. and a d-latch pushbutton for user to 'send' input. am using a 4-bit comparator 74'85 and [
Hello, I am newbie to FPGA an have question. I try to make 16 bit bidirectional data port so I can write value to 16 bit latch to turn on led's and read input switch back to microcontroller, also 16 bit memory map port to micro. When I use Quartus functional simulator I see that led port is write correctly but later in simuation the (...)
Hello Everyone, I've started in the VHDL world, mainly because my University is focused on DSPs and microcontrollers. So I've decided to do research in VHDL and FPGAs to encourage research and development in this interesting area. Well, I'm doing digital audio processing in the FGPA (XUP Virtex II-PRO). I found out that using the AC97 codec w
Hi! The Microchip data sheet for the 18F452 data sheet says Each port has three registers for its operation. These registers are: • TRIS register (data direction register) • PORT register (reads the levels on the pins of the device) • LAT register (output latch) The data latch (LAT register) is useful for read-modify
Sourcing is where the current is flowing out of the device. Sinking is when current is flowing into the device. The 74LS logic family can source a lot more current (15 - 25 mA typically) and only siink 0.4 mA. And that is why spec sheets usually have the sinking current as negative. 74HCT bus devices like a 74hc374 latch can source and sink 25 - 3
ok so my teacher wont accept the fact that the circuit he has told everone to use isnt even going to work... he has refuses to let us make our own but i dont realy care as it isnt reght that we all have to use the same circuit cos its easier fr him... so if anyone has any clues of what way i would go about doing this please tell me the curic
Hi, I'm designing a led matrix for Outdoor VMS of a considerable size (about 5meters). There are about 16 matrix. From matrix to matrix are traveling signals, like clock, data out, latch enable etc. What is the best circuit to amplify / regenerate signals? And about noise filtering (I did see (in a commercial product) some inductors in seri
hello this SMPS circuit powers the parallel led also detects if there is any open circuit led and latches the circuit off if there is any or all open circuit leds. I wish to change it so it only latches off in the event of .... "No leds lit due to failed (...)
Hi! I'm replying a little bit late, but if you haven't done the project, you should pay attention to sensitivity of the potentiometer, 'cause they can be unstable - voltage can vary in 0.01 - 0.02 up and down... Next, if i'm right pwm must be set up correctly, period must be longer than duty cycle. Changing the PWM, successively on each channel
brian i made up my mind to use cd4543 and am planning to use the current limitting resistors but in the datasheet i found a pin named latch disable???should i ve to keep that high or low?? You should not build a circuit without having the datasheets handy. The datasheet tells you what each pin does and how to do it. I get d
R can be estimated from the following assumptions: PIC output “H” ≈ 5V (PICs can source of up to 25mA per pin) Voltage drop across led inside the optocoupler => VF ≈ 1.5V I – current required to latch output ≈ 15mA (5V – 1.5V) / 15mA => 233Ω You can choose 220Ω or 240Ω, it&
There are many approaches here. If you are using a matrix keypad (such as found on a telephone), one is to use a 74HC922 . It has a "data available" output that could be latched through an external gate/FF and reset circuitry, to implement the lockout feature you desire. A BCD to
Hi, Add these two lines after the TRIS: movlw b'10000000' optionIn the datasheet it is stated A '0' puts the contents of the output data latch on the selected pins, enabling the output buffer. The exceptions are GP3 which is input only and GP2 which may be controlled by the option register, see Figure 4-5. The coding bi
with 74HC595 (see datasheet for pinout) Your Config,Picmicro,var,etc.... ; Dim chif1 as byte Dim chif2 as byte dim 7seg1 as byte dim 7seg2 as byte dim x as byte Data var PORTX.X Clock var PORTX.X latch var PORTX.X SHOut Data,Clock,msbfirst, ' clear PulsOut latch,1 DelayMS 1 PulsOut latch,1 DelayMS 1 MAIN: Fo
What IC should i use for the counter and latch? Could it be 74LS90 and 74HC4511?Yes, I think it will work. However, I think it's best to use two TTL IC's from same family as the input and output characteristics is different between different ttl familys. Also from the datasheet the data output is
Posted in error! - Sorry :)
The circuit uses a serial-in-parallel out shift register, 74HC595 for receiving serial data from uController board. See example of U5 in the schematic, SER is for data input, SRCLK is shift clock and RCLK is latch clock. Each data bit is shifted into the register on rising edge of the shift clock. When all data bits are shifted into t