Does anyone know how the grayscale palette register on EZ-driven devices
differ from the previous one? Is it on the same address?
Before posting the question, I searched the archives. There wasn't much for
this topic there and I am posting something that Edward Keyes sent me
directly, which could be of help to others browsing.
Thanks,
Bobby
www.beiks.com
The IIIx and V have a special 16-shade grayscale mode, which is presently
not supported by the PalmOS. They also can do the standard 4-shade mode
which is somewhat supported, although the palette selection register is
changed a little bit.
Anyway, here's the routine for getting into the 16-shade mode:
void GraySwitchDisplayMode(short int mode, VoidPtr *bwaddr, VoidPtr
*grayaddr)
// This performs all the register accesses to switch between grayscale and
// black and white modes. The B&W and grayscale pointers are read and
write,
// depending on which direction the mode is switching to.
// (mode=1 is switch to grayscale, mode=0 is switch to black and white)
{
ULong *SSA;
unsigned char *VPW,*PICF,*FRCM,*LBAR,*CKCON;
SSA=(ULong *)0xFFFFFA00;
VPW=(unsigned char *)0xFFFFFA05;
PICF=(unsigned char *)0xFFFFFA20;
LBAR=(unsigned char *)0xFFFFFA29;
CKCON=(unsigned char *)0xFFFFFA27;
if (mode==1) { //switch to grayscale
if ((*PICF & 0x02)==0) { // not already in grayscale mode
*bwaddr=(VoidPtr)*SSA; //save old display starting address
*CKCON=*CKCON & 0x7F; //switch off LCD update temporarily
*SSA=(ULong)*grayaddr; //set new display starting address
*VPW=40; //virtual page width now 80 bytes (160 pixels)
*PICF=*PICF | 0x02; //switch to grayscale mode
*LBAR=40; //line buffer now 80 bytes
SysTaskDelay(3); //let the LCD get to a new frame (30ms delay)
*CKCON=*CKCON | 0x80; //switch LCD back on in new mode
}
}
else if (mode==0) { //switch to black and white
if ((*PICF & 0x02)==0x02) { // not already in B&W mode
*grayaddr=(VoidPtr)*SSA; //save old display starting address
*CKCON=*CKCON & 0x7F; //switch off LCD update temporarily
*SSA=(ULong)*bwaddr; //set new display starting address
*VPW=10; //virtual page width now 20 bytes (160 pixels)
*PICF=*PICF & 0xFD; //switch to black and white mode
*LBAR=10; // line buffer now 20 bytes
SysTaskDelay(3); //let the LCD get to a new frame (30ms delay)
*CKCON=*CKCON | 0x80; //switch LCD back on in new mode
}
}
}
- Edward Keyes
[EMAIL PROTECTED]
Bobby Kolev
Software Engineer,
Interactive Edge LLC.
email: [EMAIL PROTECTED]
work: (212) 462 49000 ext.216, voice #257
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I never say never
