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Almost finished my box; Some minor questions...


robin303
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Hi Everybody !

After months of work (yep, spare time is quite rare here), I have finally finished assembling my midibox.  Wiring everything up is quite a challenge, but everything is in the box now and I finally applied power to it!  ;D

First of all I tried the ain64_din128_dout128_v1_3 and after fixing some small soldering mistakes I got all 64 buttons, 54 leds and 64 pots/faders acting the way they should. Phew.  :P

Now I have three questions:

- When entering the midibox64 menu, when I press the menu_left button, the menu seems to rapidly scroll through all options, down to the first one. And when I press the menu_right button, the options all flash by again, all the way back up to the last option. It's as if the button is 'hanging'. I did change some settings in main.asm regarding the button locations (my menu buttons are on pins 60-64). Is there some setting that I forgot?

- I had to crank up the voltage a notch because the leds and the 4x16 display, when all powered on, want some more juice. So now I give them 9 volts (from my standard 500mA adapter). My 7805 gets pretty hot now, even so hot that I can't touch its heatsink anymore without getting a burn. Is this a problem? I read about using a 7809 before the 7805, but I'm unsure where to place it.

- My 4x16 display seems to flicker. Like it has a low refresh rate. Is this something that can be cured?

BTW: I'm using Mios v1.7 (did the hardware changes) and Midibox64 v2.3

Thanks for any advice!  ::)

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Did you check how much current your whole thing needs? It´s quite unnormal that the LEDs start to flicker, also the LCD flickering is normally some less current/power.

The 7805 does get hot, but not touching it anymore? That´s heavy... forget the 7809 thing. You go in with 9 Volt, so you don´t have to go down to 9 Volt with the 7809...

The maximum (I can imagine): 7805 = (9 Volts - 5 Volts) * 500 mA = 2 Watts heat

That is pretty much indeed, but with a heatsink, this shouldn´t be the prob. I guess you still have some short somewhere in there...

btw: The prob with the button? ... ... no idea ...  :-[

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Give your 7805 a heatsink ! - When the regulator is too hot, your output voltage is dropped down.

Your display is flickering because of the voltage dropage. Your regulator is limiting the power consumption because of the heat or because of a faulty circuit after the regulator.

If your display still flickers after you give your 7805 a heatsink you should measure the current after the regulator (you have to desolder the output pin, so that you can measure between the pin and the board).

If the current is greater than 500mA your 500mA Adapter is not enough and/or  you have a fault in your Circuit which rises the power consumption.

greets

DOC

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My 7805 has a heatsink already!  :-/

I have set my 500 mA adapter to 9v, but measuring at the input pins of the core module, It is giving me around 10v. This is transformed to 5.04v. However, when I have more than, say 20 Leds, the voltage drops below 5v. When all my 54 leds are on, the voltage is around 4.5v.. Too low, right?

Anyways, to make debugging these errors a bit easier, I have now disconnected my DOUT modules. So now I have only a CORE, 2x AINX, 2x DINX, LCD connected. My circuit now has a steady 5 volts, measured from the last DINX module pins. Still I have the flickering problems.

So let's first focus on the DIN problems, withouth any DOUT modules connected.

When I turn the box on, I have a steady LCD display, no flickering whatsoever. After some time, the flickering starts. It seems that I only get flickering when both of my DIN4X modules are connected. It doesn't mather which of the two I connect. Without the DIN modules connected at all, the flickering never starts.

A colleague told me that the 74HC165 shift registers are probably starting to oscillate and advised me to solder some 10uF capacitors between pins 8 and 16 of one 74HC165  on each DINX module.  I Think I will try this tomorrow.

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I know these will be stupid questions, but I´m expert at questioning stupid questions... ;D

- You did do the hardware mod for MIOS, did you?

- What current goes in there (measure it), when you have disconnected the DOUTs? That´s important! Should not be above 300 mA without LEDs

- Do you have your Backgroundlight Pot to the max or some middle point? Put it to some middle if you don´t have already.

- What Cap do you have before the 7805? 2200 uF? 1000 uF?

- Is the Optocoupler in there the right way? It´s not the same way as the PIC is!

Just still hoping, cause 100 people used this setup and it works without any Caps on the 165s.

Greetz!

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- You did do the hardware mod for MIOS, did you?

Yes, I did the "pin 22 bankstick mod".  And I have nothing connected to J10. I don't use a SID.

- What current goes in there (measure it), when you have disconnected the DOUTs? That´s important! Should not be above 300 mA without LEDs

I'm not sure how to measure this, I'm not that technical .  When I set my Multimeter to the A 10 DC setting,  my meter says around 3.3, when set to A 10 AC setting, my meter gives me around 1.7. My midibox goes out when doing this(?)  :-/

Some voltage measurements: Adapter is set to output 9v. Measured at the pins of Core module J2  I read:

- Full load, 54 leds and lcd turned on : 8,17 v

- Only the lcd  : 10,51 v

Measured at the pins of Core module J11 I read:

- Full load, 54 leds and lcd turned on: 4,79 v

- Only the lcd  : 5,03 v

- Do you have your Backgroundlight Pot to the max or some middle point? Put it to some middle if you don´t have already.

It was at the max, I have put it in the middle now.

This will probably keep the 7805 a bit cooler. Good idea.

Now that I have done this, I can see some other strange anomalies in the lcd. In line 2, I can see, very dimly, some kind of ghost text behind the normal text.  It goes in the same frequency as the flickering..

- What Cap do you have before the 7805? 2200 uF? 1000 uF?

I build exactly as in the specs. So it's a 2200uF.

- Is the Optocoupler in there the right way? It´s not the same way as the PIC is!

Yep it's correctly placed.

Now may I ask a dumb question? Does it matter that my DINs all share one single ground line. I didn't use the ground pins for each din, instead I supplied them all with one ground line. The wires in the top are the button pins, the wires in the bottom are the led wires. The silver wire in the middle is connected to the main ground of the DIN module (J2 VS).. See the photo.

buttons_share_ground.jpg

The DIN and DOUT ground is shared as well. The white wire provides both the leds and the buttons with ground.:

buttons_share_ground2.jpg

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Hi,

I'm not sure how to measure this, I'm not that technical .  When I set my Multimeter to the A 10 DC setting,  my meter says around 3.3, when set to A 10 AC setting, my meter gives me around 1.7. My midibox goes out when doing this(?)  :-/

;) You probably made a short circuit by measuring between +5v and GND.. if multimeter and transformer survived, no harm done..

As doc said:

(you have to desolder the output pin, so that you can measure between the pin and the board).

You put the meter in circuit path, by desoldering regulators Vout pin, and connecting meter between that and boards +5v track.

Bye, Moebius

p.s. And for the debugging, you could disconnect LCDs backlight, and see if it helps. (dropping mucho overall current)

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Hi again,

the flickering is a sign for too much current !

(Typical behaviour when your 7805 is regulating down).

As you said, when you connect your DIN Module the flickering starts.

So your DIN Modules need too much current (by fault).

Again. Try to measure the Current after the regualator. Measure it with/without DIN connected and tell us the values.

You have to use the  DC A  of your multimeter and please measure between the output of the regulator and the board.

greets

Doc

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Okay, I have measured the current after the regulator.

Core + Ainx uses 0,04

Core + Ainx + Dinx uses 0,09

Core + Ainx + LCD uses 0,11

Core + Ainx + LCD + Dinx uses 0,13

After a while this raises to 0,17 (due to heat?)

Core + Ainx + LCD + Dinx + Doutx (with all 54 leds on) uses 0,65

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Hmm, I seemed to have found the cause of the flickering.. Uh, not really.  It gets weirder..  ???

I have figured out that the buttons assigned to the menu options (Left, Right, Exec, Snapshot) are causing the flickering problem.

- I configured the midibox and in MAIN.ASM,  I set pins 1,2 3 and 4 as the menu buttons

- I powered up the midibox and wait for the flickering to start

- I then disconnect the appropriate connector for these 4 pins and the flickering stops.

At first I thought this to be related to a fault with these 4 buttons. But then I re-configured the main.asm file to use another set of buttons for the menu:

- I reassigned the 4 menu buttons to pins 21, 22, 23 and 24

- The same thing happens. A few seconds after booting the display starts to flicker.

- Pulling the plug on the connector for the buttons 21 to 24 stops the flickering.

This is probably related with my other problem that also involves the menu. When I press the 'menu left' or 'menu right' button, the midibox scrolls rapidly through all the options in the menu, as if the buttons are sticky...

So basically... if I configure the midibox to not use any menu buttons at all (by specifying button numbers higher than 64 in the "DIN pin numbers of menu buttons" section of main.asm) then the flickering never occurs at all and buttons function beautifully!

It must have sometinhg to do with the software then? Any thoughts on this?

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  • 4 weeks later...

Ah, solved the problem  ;D

It seems that both the flickering of the display and the 'weird scrolling behaviour' of the left/right menu buttons where both caused by the MIOS_DIN_PinAutoRepeatEnable in the CS_MENU_Init function in cs_menu.inc:

CS_MENU_Init
      ;; clear CS stat
      clrf      CS_STAT
      ;; enable autorepeat for left and right button if datawheel not enabled
#if DEFAULT_ENC_DATAWHEEL == -1
      movlw      DEFAULT_DIN_MENU_LEFT
      call      MIOS_DIN_PinAutoRepeatEnable
      movlw      DEFAULT_DIN_MENU_RIGHT
      call      MIOS_DIN_PinAutoRepeatEnable
#endif
      ;; change to DISPLAY page and exit
      movlw      0x00
      rgoto      CS_MENU_ChangePage

So I changed the two MIOS_DIN_PinAutoRepeatEnable

to MIOS_DIN_PinAutoRepeatDisable and my problems are over!

Is this a program bug of some sorts, or does it have to do with my buttons (Reichelt DIT / DTL buttons) ?  ???

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