IBM H8 user manual Mask =

HTEB1

User manual

if (data & mask) pcnt++; mask >>= 1;

}

if ((pcnt & 0x01) ^ (data & 0x0100)) return TRUE; return FALSE;

}

interrupt [IRQ_2] void IRQ_2_Isr(void)		// irq on key_clk
{
static u8 cnt;
static u16 val;
if (outact)	/* do some output? */
{
if (outval & 0x0001) PDR1 = cKEYDATA;
else PDR1 &= ~cKEYDATA;
outval >>= 1;
if (!outval)
{
PDR1 = cKEYDATA;		// set out=HIGH (1)
PCR1 &= ~cKEYDATA;		// set portpin as input (0)
outact=0;
}
}
else		// process input data
{

val >>= 1;

if (PDR1 & cKEYDATA) val = 0x0200; cnt++;

if (cnt>=11)

{

if (OddParStopCheck(val)==TRUE)

{

KeyCodeBuf[keyWriteIndex] = val; keyWriteIndex++;

if (keyWriteIndex >= cKeyBufSize) keyWriteIndex = 0; cnt = 0;

val = 0;

}
}
}
IRR1 &= ~0x04;	// clear IRQ-Flag
}
void SendKeyBoard(u8 data)	// send data to keyboard
{
u8 pcnt = 0;
u8 mask = 0x80;
outval = data 0x0600;	// stopbit + clkbit(internal)
while (mask)	// calculate odd parity
{
if (mask & data) pcnt++;
mask >>= 1;
}
if (!(pcnt & 0x01)) outval = 0x0100;		// set parity bit
PDR1 &= ~cKEYDATA;	// set data=LOW
PCR1 = cKEYDATA;		// set as output(1)
outact = 1;	// start output action
}

u8 kbhit(void)

{

if (keyReadIndex != keyWriteIndex) return TRUE; else return FALSE;

}

u16 GetKey(void)

{

u16 KeyCode;

KeyCode = KeyCodeBuf[keyReadIndex];

Issue 0.2 Page 46 07/2002