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-rw-r--r--src/devices/machine/f3853.cpp238
1 files changed, 180 insertions, 58 deletions
diff --git a/src/devices/machine/f3853.cpp b/src/devices/machine/f3853.cpp
index 85b982634bb..ef08b087d5c 100644
--- a/src/devices/machine/f3853.cpp
+++ b/src/devices/machine/f3853.cpp
@@ -1,19 +1,19 @@
// license:BSD-3-Clause
-// copyright-holders:Wilbert Pol
+// copyright-holders:Wilbert Pol, hap
/**********************************************************************
- Fairchild F3853 SRAM interface with integrated interrupt
- controller and timer (SMI)
+Fairchild F3853 SRAM interface with integrated interrupt
+controller and timer (SMI)
- This chip is a timer shift register, basically the same as in the
- F3851.
+This chip is a timer shift register, basically the same as in the
+F3851.
- Based on a datasheet obtained from www.freetradezone.com
+Based on a datasheet obtained from www.freetradezone.com
- 8-bit shift register:
- Feedback in0 = !((out3 ^ out4) ^ (out5 ^ out7))
- Interrupts are at 0xfe
- 0xff stops the register (0xfe is never reached)
+8-bit shift register:
+Feedback in0 = !((out3 ^ out4) ^ (out5 ^ out7))
+Interrupts are at 0xfe
+0xff stops the register (0xfe is never reached)
**********************************************************************/
@@ -21,18 +21,15 @@
#include "f3853.h"
-
-/***************************************************************************
- IMPLEMENTATION
-***************************************************************************/
-
//**************************************************************************
// LIVE DEVICE
//**************************************************************************
// device type definition
DEFINE_DEVICE_TYPE(F3853, f3853_device, "f3853_device", "F3853 SMI")
+DEFINE_DEVICE_TYPE(F3851, f3851_device, "f3851_device", "F3851 PSU")
DEFINE_DEVICE_TYPE(F3856, f3856_device, "f3856_device", "F3856 PSU")
+DEFINE_DEVICE_TYPE(F38T56, f38t56_device, "f38t56_device", "F38T56 PSU")
//-------------------------------------------------
// f3853_device - constructor
@@ -52,8 +49,26 @@ f3853_device::f3853_device(const machine_config &mconfig, const char *tag, devic
f3853_device(mconfig, F3853, tag, owner, clock)
{ }
+f3851_device::f3851_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock) :
+ f3853_device(mconfig, type, tag, owner, clock),
+ m_read_port{{*this}, {*this}},
+ m_write_port{{*this}, {*this}}
+{ }
+
+f3851_device::f3851_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) :
+ f3851_device(mconfig, F3851, tag, owner, clock)
+{ }
+
+f3856_device::f3856_device(const machine_config &mconfig, device_type type, const char *tag, device_t *owner, u32 clock) :
+ f3851_device(mconfig, type, tag, owner, clock)
+{ }
+
f3856_device::f3856_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) :
- f3853_device(mconfig, F3856, tag, owner, clock)
+ f3856_device(mconfig, F3856, tag, owner, clock)
+{ }
+
+f38t56_device::f38t56_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock) :
+ f3856_device(mconfig, F38T56, tag, owner, clock)
{ }
@@ -64,12 +79,25 @@ void f3853_device::device_resolve_objects()
m_int_daisy_chain_callback.bind_relative_to(*owner());
}
+void f3851_device::device_resolve_objects()
+{
+ f3853_device::device_resolve_objects();
+
+ // 2 I/O ports
+ for (devcb_read8 &cb : m_read_port)
+ cb.resolve_safe(0);
+ for (devcb_write8 &cb : m_write_port)
+ cb.resolve_safe();
+}
+
+
//-------------------------------------------------
// device_start - device-specific startup
//-------------------------------------------------
void f3853_device::device_start()
{
+ // lookup table for 3851/3853 lfsr timer
uint8_t reg = 0xfe; // Known to get 0xfe after 255 cycles
for(int i = reg; i >= 0; i--)
{
@@ -94,6 +122,18 @@ void f3853_device::device_start()
save_item(NAME(m_external_interrupt_line));
}
+void f3856_device::device_start()
+{
+ f3853_device::device_start();
+
+ m_timer_count = 0;
+ m_timer_modulo = 0;
+ m_timer_start = false;
+
+ save_item(NAME(m_timer_count));
+ save_item(NAME(m_timer_modulo));
+ save_item(NAME(m_timer_start));
+}
//-------------------------------------------------
// device_reset - device-specific reset
@@ -174,46 +214,40 @@ WRITE_LINE_MEMBER(f3853_device::pri_in_w)
READ8_MEMBER(f3853_device::read)
{
- uint8_t data = 0;
-
- switch (offset)
+ switch (offset & 3)
{
+ // interrupt vector
case 0:
- data = m_int_vector >> 8;
- break;
-
+ return m_int_vector >> 8;
case 1:
- data = m_int_vector & 0xff;
- break;
+ return m_int_vector & 0xff;
- case 2: // Interrupt control; not readable
- case 3: // Timer; not readable
- break;
+ // interrupt control, timer: write-only
+ default:
+ return 0;
}
-
- return data;
}
WRITE8_MEMBER(f3853_device::write)
{
- switch(offset)
+ switch (offset & 3)
{
+ // interrupt vector
case 0:
m_int_vector = (data << 8) | (m_int_vector & 0x00ff);
break;
-
case 1:
m_int_vector = data | (m_int_vector & 0xff00);
break;
// interrupt control
case 2:
- m_external_enable = ((data & 3) == 1);
- m_timer_enable = ((data & 3) == 3);
+ m_external_enable = (data & 3) == 1;
+ m_timer_enable = (data & 3) == 3;
set_interrupt_request_line();
break;
- // timer
+ // set timer
case 3:
m_request_flipflop = false;
set_interrupt_request_line();
@@ -223,58 +257,146 @@ WRITE8_MEMBER(f3853_device::write)
}
-READ8_MEMBER(f3856_device::read)
+READ8_MEMBER(f3851_device::read)
{
- uint8_t data = 0;
+ switch (offset & 3)
+ {
+ // I/O ports
+ case 0: case 1:
+ return (m_read_port[offset & 1])(offs_t(offset & 1));
- switch (offset)
+ // interrupt control, timer: write-only
+ default:
+ return 0;
+ }
+}
+
+WRITE8_MEMBER(f3851_device::write)
+{
+ switch (offset & 3)
{
- case 0:
+ // I/O ports
+ case 0: case 1:
+ (m_write_port[offset & 1])(offs_t(offset & 1), data);
break;
- case 1:
+ // interrupt control, timer: same as 3853
+ case 2: case 3:
+ f3853_device::write(space, offset, data);
break;
+ }
+}
- case 2:
- break;
- case 3:
- break;
+void f3856_device::timer_start(uint8_t value)
+{
+ m_timer_count = value;
+ attotime period = (m_timer_start) ? (attotime::from_hz(clock()) * m_prescaler) : attotime::never;
+
+ m_timer->adjust(period);
+}
+
+TIMER_CALLBACK_MEMBER(f3856_device::timer_callback)
+{
+ if (--m_timer_count == 0)
+ {
+ m_timer_count = m_timer_modulo;
+ if (m_timer_enable)
+ {
+ m_request_flipflop = true;
+ set_interrupt_request_line();
+ }
}
- return data;
+ timer_start(m_timer_count);
}
-WRITE8_MEMBER(f3856_device::write)
+READ8_MEMBER(f3856_device::read)
{
- switch(offset)
+ switch (offset & 3)
{
- case 0:
- break;
+ // timer: active counter
+ case 3:
+ return m_timer_count;
- case 1:
+ // other: same as 3851
+ default:
+ return f3851_device::read(space, offset);
+ }
+}
+
+WRITE8_MEMBER(f3856_device::write)
+{
+ switch (offset & 3)
+ {
+ // I/O ports: same as 3851
+ case 0: case 1:
+ f3851_device::write(space, offset, data);
break;
// interrupt control
case 2:
- // timer prescaler in high 3 bits
- static const u8 prescaler[8] = { 0, 2, 5, 10, 20, 40, 100, 200 };
+ {
+ // timer prescaler
+ static const u8 prescaler[8] = { 32, 128, 8, 2 };
m_prescaler = prescaler[data >> 5 & 7];
- // TODO: event counter mode
- if (m_prescaler == 0)
- m_prescaler = 100;
+ // start/stop timer
+ bool prev = m_timer_start;
+ m_timer_start = bool(~data & 0x10);
+ if (m_timer_start != prev)
+ timer_start(m_timer_count);
- m_external_enable = bool(data & 1);
+ // enable interrupts
+ m_external_enable = (data & 3) == 1 || (data & 3) == 2;
m_timer_enable = bool(data & 2);
set_interrupt_request_line();
break;
+ }
- // timer
+ // set timer
case 3:
- m_request_flipflop = false;
+ f3853_device::write(space, offset, data);
+ break;
+ }
+}
+
+
+WRITE8_MEMBER(f38t56_device::write)
+{
+ switch (offset & 3)
+ {
+ // I/O ports: same as 3851
+ default:
+ f3851_device::write(space, offset, data);
+ break;
+
+ // interrupt control
+ case 2:
+ {
+ // timer prescaler
+ m_prescaler = 200;
+ if (~data & 0x80) m_prescaler /= 20;
+ if (~data & 0x40) m_prescaler /= 5;
+ if (~data & 0x20) m_prescaler /= 2;
+
+ // start/stop timer
+ bool prev = m_timer_start;
+ m_timer_start = bool(data & 8);
+ if (m_timer_start != prev)
+ timer_start(m_timer_count);
+
+ // enable interrupts
+ m_external_enable = bool(data & 1);
+ m_timer_enable = bool(data & 2);
set_interrupt_request_line();
- timer_start(data);
+ break;
+ }
+
+ // set timer
+ case 3:
+ m_timer_modulo = data;
+ f3853_device::write(space, offset, data);
break;
}
}