63 Threads found on edaboard.com: Latch Led
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...
Microcontrollers :: 08.12.2003 13:16 :: msmax :: Replies: 29 :: Views: 14175
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?
Professional Hardware and Electronics Design :: 25.11.2003 21:44 :: PicsOne :: Replies: 3 :: Views: 1079
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 (...)
Microcontrollers :: 28.10.2004 11:20 :: DaveFrawley :: Replies: 3 :: Views: 1193
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 (...)
Electronic Elementary Questions :: 05.01.2005 22:52 :: e_eja :: Replies: 1 :: Views: 1066
You can use this latch IC 74HC273. It has 8 D-FlipFlops.
Electronic Elementary Questions :: 13.10.2005 23:50 :: seadolphine2000 :: Replies: 3 :: Views: 944
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
Professional Hardware and Electronics Design :: 24.11.2005 22:02 :: Sugiman :: Replies: 1 :: Views: 2405
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
Microcontrollers :: 09.02.2006 21:41 :: sp :: Replies: 9 :: Views: 3269
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 (...)
Microcontrollers :: 04.05.2007 08:21 :: skn82 :: Replies: 0 :: Views: 490
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
Microcontrollers :: 23.02.2008 23:49 :: Siniąa :: Replies: 4 :: Views: 1395
better way is to use latch and no multiplaxing.
directly use latch and use mcu behind it
Microcontrollers :: 19.07.2008 10:30 :: Noman Yousaf :: Replies: 6 :: Views: 2334
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 (...)
Electronic Elementary Questions :: 15.04.2009 05:13 :: PRAVEEN K :: Replies: 13 :: Views: 13592
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.
Outstring = ">>>>>>>>"
Gosub Processoutstring 'This procedure transform the message in a bit array
For A = 1 To Outarraycounter ' Arraycounter is the lenght of array
Microcontrollers :: 09.06.2009 10:26 :: Codeman :: Replies: 2 :: Views: 953
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 ..
Hobby Circuits and Small Projects Problems :: 08.04.2010 00:46 :: IanP :: Replies: 2 :: Views: 1470
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
Microcontrollers :: 02.06.2010 14:46 :: rushi53 :: Replies: 4 :: Views: 1358
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.
Microcontrollers :: 22.07.2010 11:07 :: tictac :: Replies: 14 :: Views: 1056
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.
Analog Circuit Design :: 05.11.2010 10:38 :: allennlowaton :: Replies: 0 :: Views: 635
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
Hobby Circuits and Small Projects Problems :: 14.11.2010 14:15 :: ZASto :: Replies: 28 :: Views: 5456
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
Microcontrollers :: 30.01.2011 14:37 :: deniah :: Replies: 3 :: Views: 773
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 (...)
Hobby Circuits and Small Projects Problems :: 22.03.2011 13:21 :: Err404 :: Replies: 8 :: Views: 2155
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 (...)
Hobby Circuits and Small Projects Problems :: 09.04.2011 23:36 :: jstamour802 :: Replies: 0 :: Views: 1994
In the following code
void sen_data(unsigned char c)
unsigned char i,k;
SCK = 0;
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
Microcontrollers :: 24.05.2011 08:32 :: deeplearns :: Replies: 4 :: Views: 1102
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?
Hobby Circuits and Small Projects Problems :: 07.07.2011 11:18 :: Prototyp_V1.0 :: Replies: 3 :: Views: 1511
Thanks a lot,
I will check the enable and latch carefully.
Microcontrollers :: 02.02.2012 04:15 :: ultrabrains :: Replies: 2 :: Views: 342
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.
Microcontrollers :: 02.04.2012 23:36 :: rajesh279 :: Replies: 1 :: Views: 892
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 (...)
PLD, SPLD, GAL, CPLD, FPGA Design :: 13.07.2012 18:53 :: rberek :: Replies: 6 :: Views: 1713
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,
Analog Circuit Design :: 08.10.2012 12:13 :: gone :: Replies: 1 :: Views: 227
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 (...)
RF, Microwave, Antennas and Optics :: 09.10.2012 16:27 :: bhadresh :: Replies: 5 :: Views: 1095
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
Microcontrollers :: 25.10.2012 00:15 :: BhavaniT :: Replies: 4 :: Views: 281
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?
Microcontrollers :: 22.11.2012 23:39 :: paddy_p :: Replies: 7 :: Views: 327
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>
Clear LATA and ANSEL
Microcontrollers :: 09.02.2013 16:41 :: nagkiller :: Replies: 8 :: Views: 1061
You should use three outputs of micro. Data, Clock, Strobe
Set clock to zero
Set data (zero or one)
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
Digital Signal Processing :: 18.02.2013 16:50 :: boldstone :: Replies: 1 :: Views: 638
'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
Electronic Elementary Questions :: 27.08.2013 04:50 :: kripacharya :: Replies: 20 :: Views: 719
Audible Alarms Circuits
Coil Q Tester
Fluid Level Monitor
Fluorescent Lamp Circuits
Software Links :: 28.03.2004 11:18 :: alcindo :: Replies: 0 :: Views: 1411
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 [
Hobby Circuits and Small Projects Problems :: 27.09.2004 10:19 :: darkad :: Replies: 0 :: Views: 655
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 (...)
PLD, SPLD, GAL, CPLD, FPGA Design :: 25.11.2005 19:22 :: QUART :: Replies: 0 :: Views: 601
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
PLD, SPLD, GAL, CPLD, FPGA Design :: 06.12.2006 11:48 :: Muhon :: Replies: 0 :: Views: 631
The Microchip data sheet for the 18F452 data sheet says
Each port has three registers for its operation. These
• TRIS register (data direction register)
• PORT register (reads the levels on the pins of the
• LAT register (output latch)
The data latch (LAT register) is useful for read-modify
Microcontrollers :: 04.05.2007 00:23 :: waseem :: Replies: 2 :: Views: 9054
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
Microcontrollers :: 06.05.2007 00:04 :: jhbbunch :: Replies: 4 :: Views: 4007
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
Hobby Circuits and Small Projects Problems :: 28.09.2007 06:25 :: devildonebad :: Replies: 3 :: Views: 1341
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
Professional Hardware and Electronics Design :: 12.08.2008 09:23 :: Codeman :: Replies: 0 :: Views: 894
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 (...)
Analog Circuit Design :: 24.07.2009 08:30 :: eem2am :: Replies: 0 :: Views: 474
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
Microcontrollers :: 01.08.2009 20:20 :: wizardgrt :: Replies: 5 :: Views: 1134
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
Electronic Elementary Questions :: 05.10.2009 16:29 :: Audioguru :: Replies: 16 :: Views: 2265
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&
Microcontrollers :: 07.03.2010 00:18 :: IanP :: Replies: 14 :: Views: 2735
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
PLD, SPLD, GAL, CPLD, FPGA Design :: 27.10.2010 12:51 :: djsfantasi :: Replies: 4 :: Views: 3327
Add these two lines after the TRIS:
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
Microcontrollers :: 22.12.2010 22:26 :: Tahmid :: Replies: 2 :: Views: 806
with 74HC595 (see datasheet for pinout)
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
Microcontrollers :: 02.02.2011 23:34 :: cocoloco :: Replies: 1 :: Views: 502
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
Analog Circuit Design :: 01.03.2011 11:33 :: Prototyp_V1.0 :: Replies: 6 :: Views: 1381
Posted in error! - Sorry :)
Hobby Circuits and Small Projects Problems :: 22.03.2011 13:29 :: Err404 :: Replies: 1 :: Views: 925
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
Electronic Elementary Questions :: 20.06.2011 13:08 :: mister_rf :: Replies: 6 :: Views: 1740