// license:BSD-3-Clause // copyright-holders:Nigel Barnes /********************************************************************** Watford Electronics 32K RAM card http://chrisacorns.computinghistory.org.uk/8bit_Upgrades/WE_32KRAMcard.html **********************************************************************/ #include "emu.h" #include "we32kram.h" //************************************************************************** // DEVICE DEFINITIONS //************************************************************************** DEFINE_DEVICE_TYPE(BBC_WE32KRAM, bbc_we32kram_device, "bbc_we32kram", "Watford Electronics 32K Shadow RAM"); //------------------------------------------------- // ROM( we32kram ) //------------------------------------------------- ROM_START(we32kram) ROM_REGION(0x4000, "exp_rom", 0) ROM_SYSTEM_BIOS(0, "240", "v2.40") ROMX_LOAD("we32kram_v2.40.rom", 0x0000, 0x2000, CRC(db9c3a1a) SHA1(0a5efb084eb1ae353b9c79c026e9e26cd7695293), ROM_BIOS(0)) ROM_SYSTEM_BIOS(1, "220", "v2.20") ROMX_LOAD("we32kram_v2.20.rom", 0x0000, 0x2000, CRC(bc7124e0) SHA1(7f8536576de449916cd77488e94775ed438c5c6c), ROM_BIOS(1)) ROM_SYSTEM_BIOS(2, "200", "v2.00") ROMX_LOAD("we32kram_v2.00.rom", 0x0000, 0x2000, CRC(1eff9b23) SHA1(98a3084b20c92427c2e9def58ade96f42659e20a), ROM_BIOS(2)) ROM_SYSTEM_BIOS(3, "106", "v1.06") ROMX_LOAD("we32kram_v1.06.rom", 0x0000, 0x2000, CRC(b9749390) SHA1(210f6162d634fca8d75197d4f64d9b50abc01e1e), ROM_BIOS(3)) ROM_SYSTEM_BIOS(4, "100", "v1.00") ROMX_LOAD("we32kram_v1.00.rom", 0x0000, 0x2000, CRC(7962b5db) SHA1(1b59a3354cfc704ad8aa60b0ed16e4cd2d815031), ROM_BIOS(4)) ROM_END //------------------------------------------------- // rom_region - device-specific ROM region //------------------------------------------------- const tiny_rom_entry *bbc_we32kram_device::device_rom_region() const { return ROM_NAME(we32kram); } //************************************************************************** // LIVE DEVICE //************************************************************************** //------------------------------------------------- // bbc_we32kram_device - constructor //------------------------------------------------- bbc_we32kram_device::bbc_we32kram_device(const machine_config &mconfig, const char *tag, device_t *owner, uint32_t clock) : device_t(mconfig, BBC_WE32KRAM, tag, owner, clock) , device_bbc_internal_interface(mconfig, *this) { } //------------------------------------------------- // device_start - device-specific startup //------------------------------------------------- void bbc_we32kram_device::device_start() { m_shadow = 2; m_ram = std::make_unique(0x8000); /* register for save states */ save_item(NAME(m_shadow)); save_pointer(NAME(m_ram), 0x8000); } //------------------------------------------------- // device_reset - device-specific reset //------------------------------------------------- void bbc_we32kram_device::device_reset() { address_space &program = m_maincpu->space(AS_PROGRAM); program.install_write_handler(0xfffc, 0xffff, write8sm_delegate(*this, FUNC(bbc_we32kram_device::control_w))); } //************************************************************************** // IMPLEMENTATION //************************************************************************** void bbc_we32kram_device::control_w(offs_t offset, uint8_t data) { m_shadow = offset; } uint8_t bbc_we32kram_device::ram_r(offs_t offset) { uint8_t data = 0xff; switch (m_shadow) { case 0: /* &fffc - swap whole memory */ data = m_ram[offset]; break; case 2: /* &fffe - select BBC ram */ data = m_mb_ram->pointer()[offset]; break; case 3: /* &ffff - select Watford ram */ if (offset >= 0x3000) data = m_ram[offset]; else data = m_mb_ram->pointer()[offset]; break; } return data; } void bbc_we32kram_device::ram_w(offs_t offset, uint8_t data) { switch (m_shadow) { case 0: /* &fffc - swap whole memory */ m_ram[offset] = data; break; case 2: /* &fffe - select BBC ram */ m_mb_ram->pointer()[offset] = data; break; case 3: /* &ffff - select Watford ram */ if (offset >= 0x3000) m_ram[offset] = data; else m_mb_ram->pointer()[offset] = data; break; } }