diff options
Diffstat (limited to 'src/mame/machine/bigevglf.c')
-rw-r--r-- | src/mame/machine/bigevglf.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/src/mame/machine/bigevglf.c b/src/mame/machine/bigevglf.c new file mode 100644 index 00000000000..92307ed20e7 --- /dev/null +++ b/src/mame/machine/bigevglf.c @@ -0,0 +1,107 @@ +/*************************************************************************** + + machine.c + + Functions to emulate general aspects of the machine (RAM, ROM, interrupts, + I/O ports) + +***************************************************************************/ + +#include "driver.h" + + +static UINT8 from_mcu; +static int mcu_sent = 0,main_sent = 0; + + +static UINT8 portA_in,portA_out,ddrA; +static UINT8 portB_in,portB_out,ddrB; +static UINT8 portC_in,portC_out,ddrC; + +READ8_HANDLER( bigevglf_68705_portA_r ) +{ + return (portA_out & ddrA) | (portA_in & ~ddrA); +} + +WRITE8_HANDLER( bigevglf_68705_portA_w ) +{ + portA_out = data; +} + +WRITE8_HANDLER( bigevglf_68705_ddrA_w ) +{ + ddrA = data; + +} + +READ8_HANDLER( bigevglf_68705_portB_r ) +{ + return (portB_out & ddrB) | (portB_in & ~ddrB); +} + +WRITE8_HANDLER( bigevglf_68705_portB_w ) +{ + + if ((ddrB & 0x02) && (~portB_out & 0x02) && (data & 0x02)) /* positive going transition of the clock */ + { + cpunum_set_input_line(3,0,CLEAR_LINE); + main_sent = 0; + + } + if ((ddrB & 0x04) && (~portB_out & 0x04) && (data & 0x04) ) /* positive going transition of the clock */ + { + from_mcu = portA_out; + mcu_sent = 0; + } + + portB_out = data; +} + +WRITE8_HANDLER( bigevglf_68705_ddrB_w ) +{ + ddrB = data; +} + +READ8_HANDLER( bigevglf_68705_portC_r ) +{ + portC_in = 0; + if (main_sent) portC_in |= 0x01; + if (mcu_sent) portC_in |= 0x02; + + return (portC_out & ddrC) | (portC_in & ~ddrC); +} + +WRITE8_HANDLER( bigevglf_68705_portC_w ) +{ + portC_out = data; +} + +WRITE8_HANDLER( bigevglf_68705_ddrC_w ) +{ + ddrC = data; +} + +WRITE8_HANDLER( bigevglf_mcu_w ) +{ + portA_in = data; + main_sent = 1; + cpunum_set_input_line(3,0,ASSERT_LINE); +} + + +READ8_HANDLER( bigevglf_mcu_r ) +{ + mcu_sent = 1; + return from_mcu; +} + +READ8_HANDLER( bigevglf_mcu_status_r ) +{ + int res = 0; + + if (!main_sent) res |= 0x08; + if (!mcu_sent) res |= 0x10; + + return res; +} + |