/* signal a code has been received */
void pcw16_state::pcw16_keyboard_signal_byte_received(int data)
{
/* clear clock */
pcw16_keyboard_set_clock_state(0);
/* set code in shift register */
m_keyboard_data_shift = data;
/* busy */
m_keyboard_state |= PCW16_KEYBOARD_BUSY_STATUS;
/* initialise start, stop and parity bits */
m_keyboard_state &= ~PCW16_KEYBOARD_START_BIT_MASK;
m_keyboard_state |=PCW16_KEYBOARD_STOP_BIT_MASK;
/* "Keyboard data has odd parity, so the parity bit in the
status register should only be set when the shift register
data itself has even parity. */
m_keyboard_state &= ~PCW16_KEYBOARD_PARITY_MASK;
/* if data has even parity, set parity bit */
if ((m_keyboard_parity_table[data])==0)
m_keyboard_state |= PCW16_KEYBOARD_PARITY_MASK;
pcw16_keyboard_int(1);
}
static WRITE8_HANDLER(pcw16_keyboard_control_w)
{
//logerror("Keyboard control w: %02x\n",data);
pcw16_keyboard_previous_state = pcw16_keyboard_state;
/* if set, set parity */
if (data & 0x080)
{
pcw16_keyboard_state |= PCW16_KEYBOARD_PARITY_MASK;
}
/* clear read/write bits */
pcw16_keyboard_state &=
~(PCW16_KEYBOARD_FORCE_KEYBOARD_CLOCK |
PCW16_KEYBOARD_TRANSMIT_MODE);
/* set read/write bits from data */
pcw16_keyboard_state |= (data & 0x03);
if (data & PCW16_KEYBOARD_RESET_INTERFACE)
{
pcw16_keyboard_reset();
}
if (data & PCW16_KEYBOARD_TRANSMIT_MODE)
{
/* force clock changed */
if (((pcw16_keyboard_state^pcw16_keyboard_previous_state) & PCW16_KEYBOARD_FORCE_KEYBOARD_CLOCK)!=0)
{
/* just cleared? */
if ((pcw16_keyboard_state & PCW16_KEYBOARD_FORCE_KEYBOARD_CLOCK)==0)
{
/* write */
/* busy */
pcw16_keyboard_state |= PCW16_KEYBOARD_BUSY_STATUS;
/* keyboard takes data */
at_keyboard_write(pcw16_keyboard_data_shift);
/* set clock low - no furthur transmissions */
pcw16_keyboard_set_clock_state(0);
/* set int */
pcw16_keyboard_int(1);
}
}
}
if (((pcw16_keyboard_state^pcw16_keyboard_previous_state) & PCW16_KEYBOARD_TRANSMIT_MODE)!=0)
{
if ((pcw16_keyboard_state & PCW16_KEYBOARD_TRANSMIT_MODE)==0)
{
if ((pcw16_system_status & (1<<1))!=0)
{
pcw16_keyboard_int(0);
}
}
}
pcw16_keyboard_refresh_outputs();
}
void pcw16_state::pcw16_keyboard_reset()
{
/* clock set to high */
pcw16_keyboard_set_clock_state(1);
}
static void pcw16_keyboard_reset(void)
{
/* clock set to high */
pcw16_keyboard_set_clock_state(1);
}
