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CIA 6526: Fixed serial port transfer.

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This commit is contained in:
Curt Coder 2010-01-21 18:30:50 +00:00
parent 83e4bf73d8
commit b05bd546aa
1 changed files with 77 additions and 73 deletions
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150
src/emu/machine/6526cia.c
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@ -32,6 +32,15 @@
#define CIA_CRA 14
#define CIA_CRB 15
#define CIA_CRA_START 0x01
#define CIA_CRA_PBON 0x02
#define CIA_CRA_OUTMODE 0x04
#define CIA_CRA_RUNMODE 0x08
#define CIA_CRA_LOAD 0x10
#define CIA_CRA_INMODE 0x20
#define CIA_CRA_SPMODE 0x40
#define CIA_CRA_TODIN 0x80
/***************************************************************************
TYPE DEFINITIONS
***************************************************************************/
@ -158,6 +167,10 @@ static DEVICE_RESET( cia )
cia->icr = 0x00;
cia->ics = 0x00;
cia->irq = 0;
cia->shift = 0;
cia->loaded = 0;
cia->cnt = 1;
cia->sp = 0;
/* initialize data direction registers */
cia->port[0].ddr = !strcmp(device->tag, "cia_0") ? 0x03 : 0xff;
@ -346,36 +359,48 @@ static void cia_timer_underflow(running_device *device, int timer)
}
/* also the serial line */
if ((cia->timer[timer].irq == 0x01) && (cia->timer[timer].mode & 0x40))
if ((cia->timer[timer].irq == 0x01) && (cia->timer[timer].mode & CIA_CRA_SPMODE))
{
if (cia->shift || cia->loaded)
if (cia->loaded || cia->shift)
{
/* falling edge */
if (cia->cnt)
{
if (cia->shift == 0)
{
/* load shift register */
cia->loaded = 0;
cia->serial = cia->sdr;
}
cia->sp = (cia->serial & 0x80) ? 1 : 0;
cia->shift++;
cia->serial <<= 1;
cia->cnt = 0;
/* transmit MSB */
cia->sp = BIT(cia->serial, 7);
devcb_call_write_line(&cia->out_sp_func, cia->sp);
/* toggle CNT */
cia->cnt = !cia->cnt;
devcb_call_write_line(&cia->out_cnt_func, cia->cnt);
/* shift data */
cia->serial <<= 1;
cia->shift++;
if (cia->shift == 8)
{
/* signal interrupt */
cia->ics |= 0x08;
cia_update_interrupts(device);
}
}
else
{
cia->cnt = 1;
/* toggle CNT */
cia->cnt = !cia->cnt;
devcb_call_write_line(&cia->out_cnt_func, cia->cnt);
if (cia->shift == 8)
{
cia->shift = 0;
cia->ics |= 0x08;
cia_update_interrupts(device);
}
}
}
@ -495,66 +520,6 @@ static TIMER_CALLBACK( cia_clock_tod_callback )
cia_clock_tod(device);
}
/*-------------------------------------------------
cia_issue_index
-------------------------------------------------*/
static void cia_issue_index(running_device *device)
{
cia_state *cia = get_token(device);
cia->ics |= 0x10;
cia_update_interrupts(device);
}
/*-------------------------------------------------
cia_set_input_sp
-------------------------------------------------*/
static void cia_set_input_sp(running_device *device, int data)
{
cia_state *cia = get_token(device);
cia->sp = data;
}
/*-------------------------------------------------
cia_set_input_cnt
-------------------------------------------------*/
static void cia_set_input_cnt(running_device *device, int data)
{
cia_state *cia = get_token(device);
/* is this a rising edge? */
if (!cia->cnt && data)
{
/* does timer #0 bump on CNT? */
if ((cia->timer[0].mode & 0x21) == 0x21)
cia_timer_bump(device, 0);
/* does timer #1 bump on CNT? */
if ((cia->timer[1].mode & 0x61) == 0x21)
cia_timer_bump(device, 1);
/* if the serial port is set to output, the CNT will shift the port */
if (!(cia->timer[0].mode & 0x40))
{
cia->serial >>= 1;
if (cia->sp)
cia->serial |= 0x80;
if (++cia->shift == 8)
{
cia->sdr = cia->serial;
cia->serial = 0;
cia->shift = 0;
cia->ics |= 0x08;
cia_update_interrupts(device);
}
}
}
cia->cnt = data ? 1 : 0;
}
READ8_DEVICE_HANDLER( mos6526_pa_r )
{
return (get_token(device)->port[0].latch | ~get_token(device)->port[0].ddr);
@ -586,7 +551,42 @@ READ_LINE_DEVICE_HANDLER( mos6526_cnt_r )
WRITE_LINE_DEVICE_HANDLER( mos6526_cnt_w )
{
cia_set_input_cnt(device, state);
cia_state *cia = get_token(device);
/* is this a rising edge? */
if (!cia->cnt && state)
{
if (cia->timer[0].mode & CIA_CRA_START)
{
/* does timer #0 bump on CNT? */
if (cia->timer[0].mode & CIA_CRA_INMODE)
cia_timer_bump(device, 0);
}
/* if the serial port is set to input, the CNT will shift the port */
if (!(cia->timer[0].mode & CIA_CRA_SPMODE))
{
cia->serial <<= 1;
cia->shift++;
if (cia->sp) cia->serial |= 0x01;
if (cia->shift == 8)
{
cia->sdr = cia->serial;
cia->serial = 0;
cia->shift = 0;
cia->ics |= 0x08;
cia_update_interrupts(device);
}
}
/* does timer #1 bump on CNT? */
if ((cia->timer[1].mode & 0x61) == 0x21)
cia_timer_bump(device, 1);
}
cia->cnt = state;
}
READ_LINE_DEVICE_HANDLER( mos6526_sp_r )
@ -598,16 +598,20 @@ READ_LINE_DEVICE_HANDLER( mos6526_sp_r )
WRITE_LINE_DEVICE_HANDLER( mos6526_sp_w )
{
cia_set_input_sp(device, state);
cia_state *cia = get_token(device);
cia->sp = state;
}
WRITE_LINE_DEVICE_HANDLER( mos6526_flag_w )
{
cia_state *cia = get_token(device);
/* falling edge */
if (cia->flag && !state)
{
cia_issue_index(device);
cia->ics |= 0x10;
cia_update_interrupts(device);
}
cia->flag = state;