diff options
Diffstat (limited to 'src/devices/bus/archimedes/podule/ether1.cpp')
-rw-r--r-- | src/devices/bus/archimedes/podule/ether1.cpp | 184 |
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 new file mode 100644 index 00000000000..e4e23704360 --- /dev/null +++ b/src/devices/bus/archimedes/podule/ether1.cpp @@ -0,0 +1,184 @@ +// 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") |