Only half of the charmap is working

[sigmounte]

Hello ,

i got my hand on an XBT-C7220 , they use 2 Rockwell 10937

Every thing look good except the charmap is strangely working :

When i ask for @abcdefghijk , i got @@CCDDGGHHKK

Even when i change the setCursor , when is ask for cursor pos 0,1,2,3,4,5,6,7 the text start at 0,1,1,4,4,5,5,8

i've tried to slow down the timing , i've checked with my scope that the reset is working correctly , eveything is fine .

it look like a problem with second lsb ;(

Do you have any idea ?

Thanks !

[sigmounte]

Tried to wire the other Rockwell 10937 , and it does exactly the sames , that does mean that i've not broke anything electrically ..

[sigmounte]

Measured it on the intel CPU that drived the display , two things are differents :

• internal timing is 550uS between each byte
• the sleep state of CLK is LOW , not HIGH

Changed the sendCommand function to this , and it work perfectly

void Samsung_16LF01_VFD::sendCommand(uint8_t data) {
byte bitRea;

for (int i=7; i>=0; i--) {

bitRea = bitRead(data, i);


    
digitalWrite(_sclk_pin, HIGH);
delayMicroseconds(1);
digitalWrite(_data_pin, bitRea);
delayMicroseconds(1);
digitalWrite(_sclk_pin, LOW); 
delayMicroseconds(2);
//digitalWrite(_sclk_pin, HIGH);

// Internal processing time (40us)

}

// internal processing time measured from a working Rockwell 10937
  delayMicroseconds(550);

}