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-rw-r--r--src/devices/bus/archimedes/podule/ether1.cpp184
1 files changed, 184 insertions, 0 deletions
diff --git a/src/devices/bus/archimedes/podule/ether1.cpp b/src/devices/bus/archimedes/podule/ether1.cpp
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+++ b/src/devices/bus/archimedes/podule/ether1.cpp
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+// license:BSD-3-Clause
+// copyright-holders:Nigel Barnes
+/**********************************************************************
+
+ Acorn AKA25 Ethernet
+
+ http://chrisacorns.computinghistory.org.uk/32bit_UpgradesA2G/Acorn_AKA25_Ethernet.html
+
+**********************************************************************/
+
+#include "emu.h"
+#include "ether1.h"
+#include "machine/i82586.h"
+
+
+namespace {
+
+class arc_ether1_aka25_device :
+ public device_t,
+ public device_archimedes_podule_interface
+{
+public:
+ // construction/destruction
+ arc_ether1_aka25_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock);
+
+protected:
+ // device-level overrides
+ virtual void device_start() override;
+ virtual void device_reset() override;
+
+ // optional information overrides
+ virtual void device_add_mconfig(machine_config &config) override;
+ virtual const tiny_rom_entry *device_rom_region() const override;
+
+ // device_archimedes_podule_interface overrides
+ virtual void ioc_map(address_map &map) override;
+
+private:
+ required_memory_region m_podule_rom;
+ required_shared_ptr<u16> m_ram;
+ required_device<i82586_device> m_lance;
+
+ void lan_map(address_map &map);
+
+ void checksum();
+ void control_w(u8 data);
+
+ u8 m_rom_page;
+ u8 m_ram_page;
+};
+
+
+void arc_ether1_aka25_device::ioc_map(address_map &map)
+{
+ map(0x0000, 0x003f).lr8(NAME([this](offs_t offset) { return m_podule_rom->base()[offset | ((m_rom_page << 4) & 0x1f)]; })).umask32(0x000000ff);
+ map(0x0000, 0x0000).lw8(NAME([this](u8 data) { m_ram_page = data & 0x0f; }));
+ map(0x0004, 0x0004).w(FUNC(arc_ether1_aka25_device::control_w));
+ map(0x2000, 0x3fff).lrw8(NAME([this](offs_t offset) { return m_ram[offset | (m_ram_page << 11)]; }), NAME([this](offs_t offset, u16 data) { m_ram[offset | (m_ram_page << 11)] = data; })).umask32(0x0000ffff);
+}
+
+
+void arc_ether1_aka25_device::lan_map(address_map &map)
+{
+ map(0x000000, 0x00ffff).mirror(0xff0000).ram().share("ram");
+}
+
+
+//-------------------------------------------------
+// device_add_mconfig - add device configuration
+//-------------------------------------------------
+
+void arc_ether1_aka25_device::device_add_mconfig(machine_config &config)
+{
+ I82586(config, m_lance, 20_MHz_XTAL / 2);
+ m_lance->out_irq_cb().set([this](int state) { m_rom_page = state; set_pirq(state); });
+ m_lance->set_addrmap(0, &arc_ether1_aka25_device::lan_map);
+}
+
+
+//-------------------------------------------------
+// ROM( ether1_aka25 )
+//-------------------------------------------------
+
+ROM_START( ether1_aka25 )
+ ROM_REGION(0x20, "podule_rom", 0)
+ ROM_LOAD("27ls19.bin", 0x00, 0x20, CRC(e034ae68) SHA1(9a9404028d166d9cbb466513f514be5d3ea77956))
+ROM_END
+
+const tiny_rom_entry *arc_ether1_aka25_device::device_rom_region() const
+{
+ return ROM_NAME( ether1_aka25 );
+}
+
+
+//**************************************************************************
+// LIVE DEVICE
+//**************************************************************************
+
+//-------------------------------------------------
+// arc_ether1_aka25_device - constructor
+//-------------------------------------------------
+
+arc_ether1_aka25_device::arc_ether1_aka25_device(const machine_config &mconfig, const char *tag, device_t *owner, u32 clock)
+ : device_t(mconfig, ARC_ETHER1_AKA25, tag, owner, clock)
+ , device_archimedes_podule_interface(mconfig, *this)
+ , m_podule_rom(*this, "podule_rom")
+ , m_ram(*this, "ram")
+ , m_lance(*this, "lance")
+ , m_rom_page(0)
+ , m_ram_page(0)
+{
+}
+
+
+//-------------------------------------------------
+// device_start - device-specific startup
+//-------------------------------------------------
+
+void arc_ether1_aka25_device::device_start()
+{
+ checksum();
+
+ save_item(NAME(m_rom_page));
+ save_item(NAME(m_ram_page));
+}
+
+//-------------------------------------------------
+// device_reset - device-specific reset
+//-------------------------------------------------
+
+void arc_ether1_aka25_device::device_reset()
+{
+ m_rom_page = 0x00;
+ m_ram_page = 0x00;
+}
+
+
+//**************************************************************************
+// IMPLEMENTATION
+//**************************************************************************
+
+void arc_ether1_aka25_device::checksum()
+{
+ // PROM CRC calculation (from A500/R200 Service Manual)
+ u32 chk = 0xffffffff;
+
+ for (int i = 0; i < 28; i++)
+ {
+ // CRC on bytes 0..28
+ u8 byte = m_podule_rom->base()[i];
+ for (int j = 0; j < 8; j++)
+ {
+ if (((byte & 1) ^ (chk >> 31)) != 0)
+ chk = (chk << 1) ^ (0x04c11db7);
+ else
+ chk = (chk << 1);
+
+ byte = byte >> 1;
+ }
+ }
+
+ // get CRC from PROM
+ u32 checksum = (m_podule_rom->base()[31] << 24) | (m_podule_rom->base()[30] << 16) | (m_podule_rom->base()[29] << 8) | (m_podule_rom->base()[28] << 0);
+
+ // test to see if the same
+ logerror("checksum: %08x %s\n", chk, checksum == chk ? "Pass" : "Fail");
+}
+
+void arc_ether1_aka25_device::control_w(u8 data)
+{
+ m_lance->reset_w(BIT(data, 0)); // b0 Reset
+ //m_sia->lpbk(BIT(data, 1)); // b1 Loop-Back
+ m_lance->ca(BIT(data, 2)); // b2 Channel Attention
+ if (BIT(data, 3)) set_pirq(0); // b3 Clear Interrupt
+}
+
+} // anonymous namespace
+
+
+//**************************************************************************
+// DEVICE DEFINITIONS
+//**************************************************************************
+
+DEFINE_DEVICE_TYPE_PRIVATE(ARC_ETHER1_AKA25, device_archimedes_podule_interface, arc_ether1_aka25_device, "arc_ether1_aka25", "Acorn AKA25 Ethernet")