I have a medusa mini and an uno. the uno writs to a character display correctly but the medusa mini does not.
Are you using ghi’s display module and driver?
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);
}
How did you wire it to the mini?
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?
They do use differen crystals. Uno is 12MHz Mini is 10MHz.
I thought UNO was 16 and mini is 12? 
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?
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.
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
@ Gus - Right. 
@ MikeCormier
I think the fix can be a simple one if you have source code for LiquidCrystal class.