"Degree" char in seven_segment.jal

[funlw65]

Hi Joep,

We don't have a "degree" char in seven_segment.jal library as here:
http://www.youtube.com/watch?v=Rp6EWOtN2PI

Vasi(funlw65)

[funlw65]

Also, here can be "J" char, from Joep :) (because I want to scrool
text "Hello JOEP" on 4 digit seven_segments using your library -
"LibrArY" :P )

[funlw65]

And also "N" char...

[Joep Suijs]

Hi Vasi,

I guess there can be 127 different chars. Feel free to add the ones you like.

Joep

2010/7/26 funlw65 <fun...@gmail.com>:

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[funlw65]

Of course, also Vasile's library but I started from your example.
Sorry for omission.
Vasi(funlw65)

P.S. It is possible also "T" char? Of course, I can extend the library
for my needs but is better to have them for everybody if
modifications. are useful.

[funlw65]

Ok then!

On Jul 26, 7:24 pm, Joep Suijs <jsu...@gmail.com> wrote:
> Hi Vasi,
>
> I guess there can be 127 different chars. Feel free to add the ones you like.
>
> Joep
>

> 2010/7/26 funlw65 <funl...@gmail.com>:

[Joep Suijs]

> Of course, I can extend the library
> for my needs but is better to have them for everybody if
> modifications. are useful.

My suggestion would be to extend the library and add the improved
library to jallib.

Joep

[Sunish Issac]

How about having a function to pass value as ascii instead of some number ? Have a function like sevenfromascii("A") prints A or "1" prints 1, i would be easier to use as the seven_seg.. file need not be reffered to.

Sunish

[vasile surducan]

   For 7 seg display: celsius degree, J and n are OK and should be added, however you can't have a real t...

About sevenfromASCII, may be good if all non numbers will be ASCII, except the hexa simbols (0-F)...

Vasile

[funlw65]

"T" can be like this (and it looks quite nice on "THIS" word):

-- __
-- /
-- /
--

And I have a proposal for the comment from the library header - to
include this:
"
.................................................................................
-- Description: Translation routine for 7 segment display.
-- --
-- The seven segment display needs to be connected to a single port.
-- Define the pin layout of the seven segment display like:
-- _a_
-- / /
-- f b
-- / /
-- _g_
-- / /
-- e c
-- / /
-- _d_
--
-- -- constant for the segments gfe dcba
.............................
"

And, in general, maybe is of some use this utility:
http://www.tech-chat.de/download.html

Vasi(funlw65)

[funlw65]

Hi,

Apologies if this was discussed... but the code 25 is reserved in
library?

Vasi(funlw65)

[vasile surducan]

On Wed, Jul 28, 2010 at 2:03 AM, funlw65 <fun...@gmail.com> wrote:

Hi,

Apologies if this was discussed... but the code 25 is reserved in
library?

No, it's just missing by mistake. 

Vasi(funlw65)

[vasi vasi]

Hi Joep and Vasile,

This is the scrolling text:
"HELLO JOEP And VASILE _ THIS USE Your LibrArY"

http://www.youtube.com/watch?v=RatJm6wGxpI

I wanted to learn how to use 4 digits as a decent display and for this, I used also timer0_isr_interval.jal (to light another 8 LED's at different speed) because I don't know yet another method of "multitasking".
I use FreeJALduino with EvB 4.3 version 4 board (with already bricked ATmega :( ) and entire assembly draws very much current, the onboard 5V regulator gets very very HOT. An external source of 5V is obligatory for this kind of application.
Anyway, the conclusion is: It is too much trouble and too many pins allocated for this task. It require a separate microcontroller for this and in this case, you can transmit data on serial. For 4 digits and 8 LEDs I used all available pins on FreeJALduino and the DOT from digits remained unconnected. But the experience gained is invaluable.

The segments get lighted on 0 logic and also digit selection is made with 0 logic (I don't know how to draw a schematic for this). The LED's are lighted also on 0 logic (this is easy, but program inside is for 1 logic - I must negate the byte). In the movie, the digits are lighted one at the time, 350uS long each but I modified the program for 950uS each to get rid of that echo. If is useful, I think it can be easily modified for Jaluino. All required files attached.
--
Vasi

[Florin Tanasa]

Hi Vasi,
I like what you done.

2010/7/28 vasi vasi <fun...@gmail.com>

--

[funlw65]

Multumesc! - Thank you!

On Jul 28, 9:58 pm, Florin Tanasa <florin.tan...@gmail.com> wrote:
> Hi Vasi,
> I like what you done.
>

> 2010/7/28 vasi vasi <funl...@gmail.com>

> > jallib+un...@googlegroups.com<jallib%2Bunsu...@googlegroups.com>
> > .

[vasile surducan]

On Wed, Jul 28, 2010 at 11:42 AM, vasi vasi <fun...@gmail.com> wrote:

Hi Joep and Vasile,

This is the scrolling text:
"HELLO JOEP And VASILE _ THIS USE Your LibrArY"

http://www.youtube.com/watch?v=RatJm6wGxpI

Oh boy, you are a rested (hodinit) guy too...:)

I wanted to learn how to use 4 digits as a decent display and for this, I used also timer0_isr_interval.jal (to light another 8 LED's at different speed) because I don't know yet another method of "multitasking".
I use FreeJALduino with EvB 4.3 version 4 board (with already bricked ATmega :( ) and entire assembly draws very much current, the onboard 5V regulator gets very very HOT. An external source of 5V is obligatory for this kind of application.
Anyway, the conclusion is: It is too much trouble and too many pins allocated for this task.

 

:)

   search on the internet for "gugaplexing", "charlieplexing" and other "plexing" methodes...

 

It require a separate microcontroller for this and in this case, you can transmit data on serial. For 4 digits and 8 LEDs I used all available pins on FreeJALduino and the DOT from digits remained unconnected. But the experience gained is invaluable.

The segments get lighted on 0 logic and also digit selection is made with 0 logic (I don't know how to draw a schematic for this). The LED's are lighted also on 0 logic (this is easy, but program inside is for 1 logic - I must negate the byte). In the movie, the digits are lighted one at the time, 350uS long each but I modified the program for 950uS each to get rid of that echo. If is useful, I think it can be easily modified for Jaluino. All required files attached.

Vasi, this is calling "ghosting". I've written an article about this problem but right now is in evaluation at the IEEE-Micro magazine, maybe they will reject it too, so you'll see it on my blog.... (I really hope not).

In a few words: as you can see from your movie, even taking a photo or a movie to a multiplexed display is a difficult task. Depending how display is routed to the PIC IO, there will be a ghosting situation, except if using standalone 7seg drivers between the PIC and display.

The reason is the variable voltage level on pins when they are used as input (pseudo high impedance or highZ, PIC/Atmel does not have a true highZ output circuit as old logic buffers have). A LED connected between two input pins of a PIC will light, and this is ghosting caused by un-fixed voltage level (if all highZ would have for example the theoretical VDD/2 voltage level fixed -used in all drawings-, that would not happen). The second cause of a ghosting is a bad timing multiplexing. Switch from one segment to another using highZ (meaning input), switch from one anode(cathode) to another anode(cathode) through an OFF state.

The time which one display lights gave the overall current drawn. A good choice is 1mS to 3mS for standard display, less than 1mS for high efficiency display. Between switching a shut OFF time of 50-100uS is reasonable.

Vasile

[funlw65]

Thank you for valuable info. I think all of this (completed whit what
is missing) can be part of Jallib and Jaluino documentation to avoid
reinventing the wheel...

On Jul 28, 10:28 pm, vasile surducan <vsurdu...@gmail.com> wrote:

[funlw65]

I found the schematic for the digits (is an older version but I think
it still fits):
http://and-tech.pl/EvB4.3/schemat.png

The movie posted earlier does not reflect the last changes included in
the uploaded program. I reduced a little the "ghost" effect and moved
it above displayed character, in the scroll direction so, it is less
disturbing.
http://www.youtube.com/watch?v=DRSEFmG8M0E

[vasi vasi]

"A good
choice is 1mS to 3mS for standard display, less than 1mS for high efficiency
display. Between switching a shut OFF time of 50-100uS is reasonable. "

Yes, I can confirm, I have better results with 1.5ms displaying time on each digit:
http://www.youtube.com/watch?v=AdyRymK48JI

File attached.

[vasi vasi]

ZERO "ghost" with this procedure:

Pseudocode:

- Put "space" code on buffer (this mean all segments are off)
- activate the current digit (the others are off in this moment)
- put the "real" character on buffer so will appear "instantly" on digit
- keep the digit lighted for 1.5ms

File attached
--
Vasi

[vasi vasi]

Sorry, this is the correct file

--
Vasi

[vasile surducan]

Whow, I didn't realize it can be written in this way, this is a good example for using two libraries...

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[funlw65]

Yes, this is why I appreciate so much this "multitasking" library of
Joep. On Arduino, an alternative is "millis()" function.

On Jul 29, 9:46 am, vasile surducan <vsurdu...@gmail.com> wrote:
> Whow, I didn't realize it can be written in this way, this is a good example
> for using two libraries...
>

> On Thu, Jul 29, 2010 at 5:45 AM, vasi vasi <funl...@gmail.com> wrote:
> > Sorry, this is the correct file
>

> > On Thu, Jul 29, 2010 at 5:14 AM, vasi vasi <funl...@gmail.com> wrote:
>
> >> ZERO "ghost" with this procedure:
>
> >> Pseudocode:
>
> >> - Put "space" code on buffer (this mean all segments are off)
> >> - activate the current digit (the others are off in this moment)
> >> - put the "real" character on buffer so will appear "instantly" on digit
> >> - keep the digit lighted for 1.5ms
>
> >> File attached
> >> --
> >> Vasi
>
> > --
> > Vasi
>
> > --
> > You received this message because you are subscribed to the Google Groups
> > "jallib" group.
> > To post to this group, send email to jal...@googlegroups.com.
> > To unsubscribe from this group, send email to

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> > .