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LiquidCrystal writes garbled text to lcd


#1

I have a medusa mini and an uno. the uno writs to a character display correctly but the medusa mini does not.


#2

Are you using ghi’s display module and driver?


#3

no

i’m using the std arduino liquid crystal’m using the std arduino liquid crystal

#include <LiquidCrystal.h>

// initialize the library with the numbers of the interface pins
LiquidCrystal lcd(7, 8, 9,10,12,13) ;                                                                                                                                                                                     

void setup() {

 // set up the LCD's number of columns and rows: 
  lcd.begin(20, 4);
  lcd.clear();
  // Print a message to the LCD.
  lcd.setCursor(0, 1);
  lcd.write("hello, world!");
}

void loop() {
  // set the cursor to column 0, line 1
  // (note: line 1 is the second row, since counting begins with 0):
//  lcd.setCursor(0, 1);
////  // print the number of seconds since reset:
//  lcd.print(millis()/1000);
}

#4

How did you wire it to the mini?


#5

used an extender module and jumper wire to a bread board.
used the same setup on the uno which worked but not on the mini.
my guess it is a timer issue in the mini firmware perhaps?


#6

They do use differen crystals. Uno is 12MHz Mini is 10MHz.


#7

I thought UNO was 16 and mini is 12? :slight_smile:


#8

uno is running at 16 didn’t know the mini is at 12.
shouldn’t using the liquidcrystal library and selecting the medusa mini board sync the clock cycles or am i way off here?


#9

The slower speed is due to 3v3 instead of 5v.

Not sure about the details here, but the Arduino SoftwareSerial library doesn’t work at 12MHz.


#10

so is this a issue i should be trying to fix or GHI?
I was under the assumption that all code that worked on an UNO would “just work” on the mini


#11

@ Gus - Right. :slight_smile:

@ MikeCormier

I think the fix can be a simple one if you have source code for LiquidCrystal class.