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Diffstat (limited to 'src/mame/machine/bigevglf.c')
-rw-r--r--src/mame/machine/bigevglf.c107
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;
+}
+