Discussion in "8051 Discussion Forum" started by    [email protected]    Oct 5, 2019.
Fri Oct 18 2019, 09:18 PM
#21
Hopefully you understand some of the program.
Which parts don't you understand ?
Sat Oct 19 2019, 07:05 PM
#22
sir, 3rd and 4th dot matrix display flickering,
Sat Oct 19 2019, 07:13 PM
#23
please find video attachment. 3rd & 4th display flickering, and not scroll in their order, like 1 dotmatrix to 4.
Sun Oct 20 2019, 12:21 AM
#24
Your code seems okay on my simulation
Try my code on your hardware.


Sun Oct 20 2019, 02:53 PM
#25
sir, when i on display ,sometime 3rd display is not refreshing, i again switch off display, then it refresh.



Sun Oct 20 2019, 03:02 PM
#26
sir, when i on display ,sometime 3rd display is not refreshing, i again switch off display, then it refresh.


[ Edited Sun Oct 20 2019, 03:03 PM ]
Sun Oct 20 2019, 03:09 PM
#27
Thanks for support,


[ Edited Sun Oct 20 2019, 07:06 PM ]
Mon Oct 21 2019, 09:18 AM
#28
I’ve been following this thread and looking at the example code and checking the MAX7219 datasheet. The code made sense and looked like it should work and I was ready to conclude some sort of hardware / timing problem between displays 2 and 3 when suddenly it clicked.

With four displays linked together data is effectively being clocked into a 64 bit shift register.

First 16 bits of DATA are sent then LOAD is strobed so the data is loaded into display #1.

Next 32 bits are sent (16=DATA, 16=NOP) and LOAD is strobed. The data is loaded into display #2 and display #1 gets nop.

However the original 16 bits for display #1 get shifted down the chain into display #3 so display #3 gets loaded with the display #1 data. It will briefly show a copy of display #1 until the actual display #3 data is sent which is why it flickers.

Data clocked into the shift register is not cleared after a LOAD pulse so 64 bits must always be sent to ensure all displays get loaded with NOP except for the selected display.

Something like:

Send16:
    for x=4 to 1
        if x == displayNumber
             SendDATA
        else 
             SendNOP



[ Edited Tue Oct 22 2019, 12:42 PM ]
Tue Oct 22 2019, 05:18 AM
#29


Thanks for support,

[email protected]


Thanks.

After Wimac's suggestion, I made a few changes.
Try this..


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ExperimenterUK
Sun Oct 13 2019, 12:23 AM
Log in.. then post your code in the 8051 forum
Sat Oct 12 2019, 12:18 PM
Bhadra Sajikumar
i am doing a countdown timer with 8051 for my project, unfortunately our professor had to take a leave of absence before he could teach us most of it.. can someone explain the .asm code of it for me?
Mon Sep 23 2019, 09:37 AM
Nathaniel
I am doing a project for my schools wireless security system with cameras,sensors and spot lights using 8051 micro controller, could you help me out with the design and its source code.
Wed Sep 18 2019, 10:48 PM
Caryn Kover
Thank you for your time,
ExperimenterUK
Mon Aug 05 2019, 09:09 PM
@Ismail ..post in forum, give details
Mon Aug 05 2019, 06:33 PM
Ismail balghmi
Hello. Please I won't download
ExperimenterUK
Wed Jul 24 2019, 02:47 AM
@BUSTER123 Please post in the forum
Tue Jul 23 2019, 08:13 PM
BUSTER123
hello! newbie here. i am kind of a guy who hates using ready - made existing libraries, so this helped a lot as i was trying to control and write to a character lcd display. however, i can't figure out how to set the cursor position. for example, i want to set it to the 5th column in the first row, so position 5. so according to the table, i am sending 10000101 on the 8 data lines of the lcd (register select pulled low). the cursor does not move there however. and i cant move the cursor left or right too. is it something wrong that i am doing? thank you.
ExperimenterUK
Thu Jul 11 2019, 09:55 PM
@ramos https://www.theengineeringprojects.com/2017/09/l298-motor-driver-library-proteus.html
ExperimenterUK
Thu Jul 11 2019, 09:44 PM
@praveen123. Can you give a link to the project ?

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ty, really needed it
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Mon Oct 21 2019, 09:18 AM
I’ve been following this thread and looking at the...
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Posted By [email protected]
Sun Oct 20 2019, 03:02 PM
sir, when i on display ,sometime 3rd display is no...
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Posted By [email protected]
Sun Oct 20 2019, 02:53 PM
sir, when i on display ,sometime 3rd display is no...
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Posted By ExperimenterUK
Sun Oct 20 2019, 12:21 AM
Your code seems okay on my simulationTry my code o...
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Posted By [email protected]
Sat Oct 19 2019, 07:13 PM
please find video attachment. 3rd & 4th displa...
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Posted By [email protected]
Sat Oct 19 2019, 07:05 PM
sir, 3rd and 4th dot matrix display flickering, ...
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Posted By ExperimenterUK
Fri Oct 18 2019, 09:18 PM
Hopefully you understand some of the program.Which...