Programming Dot Matrix Leds / Moving / Running Text Display
FROM : EKATRON .COM
[MICROPROCESSOR LABORATORIUM.F-MIPA]
BY bang WILLY SITANGGANG
Moving text or running text on a led matrix banner could be interesting for students to learn, and also an ispiring project that gain a curisity and a willing to do more and more. As the students can see their progress, their capabilty in programming increase as well.The project is started with making a module that performs a led matrix display, as shown below:
Then every ends of the modules were connected to built a banne
Soon after the class then the students make it work them selves in the lab
The circuit is just simple, use only shift registes ICs such as TTL 74164, or TTL 74595, or CMOS 4094. The code is also easy, the students start with the following code to display BRAM on the banner, and in a couple of minutes the students can make their own text moving on the banner.
ulang:
-------mov dptr,#d3fin
lagi:
-------clr a-------movc a,@a+dptr
-------cjne a,#0h, lanjut
-------sjmp ulanglanjut:
-------acall kirim
-------acall tunda
-------inc dptr
-------sjmp lagi
kirim:
-------mov sbuf,a
-------jnb ti,$
-------clr ti
-------rettunda:
-------mov r7,#0ffhtnd:
------- mov r6,#0ffh
-------djnz r6,$
-------djnz r7,tnd
-------ret
d3fin:
-------db 80h, 7fh, 49h, 49h, 49h, 49h, 7fh, 36h, 80h, 80h ;B
-------db 80h, 7fh, 7fh, 09h, 09h, 19h, 39h, 6fh, 46h, 80h ;R
-------db 80h, 7eh, 7fh, 09h, 09h, 09h, 09h, 7fh, 7eh, 80h ;A
-------db 7fh, 7fh, 06h, 0ch, 0ch, 06h, 7fh, 7fh, 80h, 80h, 0h ;M
The electronics circuits is just simple, so you can built your own running text at home,
when assembled on pcb will look like as the follow image
use right mouse click and click on the copy image then paste it to your directory.Have a look at the copper side below
As shown above this simple running text is just as a long line shift register in zig-zag, easy is'nt it?The AT89S8253 then is used as the microcontroller, with that micro we can save about 2000 characters in the eeprom. The memory area then is devided into 3 pages for 400 characters each text, and 3 pages for demo or animation with 50 characters maximum for each demo.The circuit is also simpleJust connect pin RXD of the AT89S8253 to pin 2 at the first IC4094 andpin TXD of the AT89S8253 to pin 3 at the first IC4094 and just left pin 15 of the IC4094 connected to Vcc for the first trial. Use the above code to test your circuit, you will see a moving text "BRAM" on the banner.
Then several blocks can be built and connected all together to get a long banner, as long as needed, we have tried for 50 metres with no problems, just special care on the PSA current need to pay attention, because the longer the banner the more current will be drawned.
untuk program selanjutnya
Mengisi HALAMAN 1
Tekan F1 muncul tulisan –P1>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Mengisi HALAMAN 2
Tekan F2 muncul tulisan –P2>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Mengisi HALAMAN 3
Tekan F3 muncul tulisan –P3>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Mengisi DEMO 1
Tekan F4 muncul tulisan –D1>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Mengisi DEMO 2
Tekan F5 muncul tulisan –D2>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Mengisi DEMO 3
Tekan F6 muncul tulisan –D3>
Ketik tulisan yang mau ditampilkan
Kalau ada yang salah dapat dihapus dengan menekan tombol Back Space
tekan spasi kemudian tekan enter
Fungsi tombol tambahanMenghapus seluruh isi halaman 1 tekan F7 pada saat running text sedang berjalanMenghapus seluruh isi halaman 2 tekan F8 pada saat running text sedang berjalanMenghapus seluruh isi halaman 3 tekan F9 pada saat running text sedang berjalan
Menghapus seluruh isi demo 1 tekan F10 pada saat running text sedang berjalanMenghapus seluruh isi demo 2 tekan F11 pada saat running text sedang berjalanMenghapus seluruh isi demo 3 tekan F12 pada saat running text sedang berjalan Mempercepat gerakan tulisan tekan tombol ESC pada saat running text sedang berjalan, perhatikan gerakan tulisan dan tekan lagi ESC sampai kecepatan yang diinginkan dicapai.Memperlambat gerakan tulisan tekan tombol TAB pada saat running text sedang berjalan, perhatikan gerakan tulisan dan tekan lagi ESC sampai kecepatan yang diinginkan dicapai. [adjie-07]
