Unitech PT600, Programming Reference Manual

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Chapter 1 BIOS and System Functions
The PT600 operating system supports DOS/BIOS function calls that a programmer
can access when developing an application for the portable.
1.1 Interrupt Vector Assignment for I/Os
Vector BIOS Function
09 H Display Font
0F H Kermit Server
10 H LCD Control
21 H System Functions
22 H Power Manager
31 H Beeper Control
33 H RS232 Control
1.2 Display Font Functions ( INT 09H )
00 Select Large Font
Entry Parameter: AH = 0/1 ; select 8*16-dot character font (4
lines * 16
; columns display)
Return Value: None
Example:
void TL_font(int status)
{
regs.h.ah = (unsigned char)status;
int86(0x09,&regs,&regs);
}
01 Select Small Font
Entry Parameter: AH = 1 ; select 6*8-dot character font (8 lines * 20
columns display)
Return Value: None
Example:
void TL_font(int status)