Pin 23 and 24 of Maple mini « LeafLabs Garden

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Pin 23 and 24 of Maple mini

(8 posts) (4 voices)

Started 4 years ago by Xavier
Latest reply from

Xavier
Moderator

Hello,

I just understood why i could not get My LCD (LiquidCrystal) working with my maple mini.
I used pin 24 among the 10 pins.

I saw in the doc i had to disable USBSerial to be able to use pins 23 and 24 but adding SerialUSB.end() did not change anything.

A second problem : i cannot make the LiquidCrystal work in 4 bits mode.
Simple example :
"LiquidCrystal lcd(2,3,4,5,6,7,27,26,25,22);" Works.
with the same hardware wiring :
"LiquidCrystal lcd(2,3,4,5,6,7);" do not Work.

Anyone else noticed that ?
Thanks for any help,

Xavier

Posted 4 years ago #
mbolivar
LeafLabs

Hi Xavier,

Re: pins 23 and 24, I've reproduced the issue and filed a ticket:

http://code.google.com/p/leaflabs/issues/detail?id=71

Fixing this bug blocks libmaple 0.0.12.

Posted 4 years ago #
Xavier
Moderator

Thanks Marti,
Should we enter bug directly in the bug tracker or do you prefer to do it yourself ?
Xavier

Posted 4 years ago #
mbolivar
LeafLabs

Feel free to choose between filing the ticket yourself and posting it here; either way is fine with me. We get email whenever anything happens on the bug tracker, so it won't get ignored.

Posted 4 years ago #

mbolivar
LeafLabs

Hey all,

Back to posting after a while absent!

I was messing around with this issue today, and the fix is simple: power off the USB peripheral. You can currently do this with usbPowerOff(), from usb.h.

Example code:

#include "usb.h"

uint8 pins[] = {23, 24, 25};

void setup() {
    SerialUSB.end();
    usbPowerOff();
    for (int i = 0; i < 3; i++) {
        pinMode(pins[i], OUTPUT);
    }
}

void loop() {
    for (int i = 0; i < 3; i++) {
        togglePin(pins[i]);
    }
    delay(50);
}

Posted 4 years ago #

kalund
Member

Hi,

I've just made a small pcb where I've been trying to use the LiquidCrystal library in 4-bit mode with the maple mini, but I can't seem to get it to work, did you ever get it working? - Unfortunatly I can't test 8-bit mode as this would mean redesigning the pcb.

/Kalund

Posted 4 years ago #
Anonymous
Unregistered

Unsure if this is related, however on a Maple r5, I run into problems using a 20x2 VFD when using 4-bit mode with the following:

RS: 23
E: 24
D4-D7: 25,26,27,28

The display runs quite nicely for a while, then after about 15 minutes or so, I start getting gibberish on the display. If I move from using pins 23-28 and instead use 25-30, the problem manifests itself within about 10 seconds. The display runs forever without incident off of an Arduino so I am certain that it is not defective. I am perplexed as to the behavior just by switching pins, but I suspect that there may be a peripheral or option that I need to disable in order to rectify this condition.

Posted 3 years ago #
Anonymous
Unregistered

I think that it is safe to disregard my comment. My apology for the thread necromancy. After building my circuit on the new prototyping board, I have been unable to reproduce the problem. I suspect that I was getting noise on my data lines.

Posted 3 years ago #

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