{"product_id":"sidecartridge®-256kb-decoder-for-mega-st","title":"SidecarTridge® 256KB Decoder for Mega ST","description":"\u003cdiv class=\"project-heading\"\u003e\u003cbr\u003e\u003c\/div\u003e\n\u003cdiv class=\"content\"\u003e\n\u003ch2 id=\"solderless-256kb-rom-decoder--tos-emulator-for-mega-st\"\u003eSolderless 256KB ROM Decoder for Atari Mega ST\u003c\/h2\u003e\n\u003cp\u003eUpgrade your Atari Mega ST to fully support 256KB TOS images without modifying the original motherboard ROM configuration. The SidecarTridge 256KB Decoder is a dedicated expansion board designed exclusively for Mega ST systems and works together with the existing SidecarTridge TOS Emulator.\u003c\/p\u003e\n\u003cp\u003eThis revision installs completely solderless through the Mega ST MEGABUS connector and transparently generates the additional address decoding and chip-enable signals required for 256KB ROM operation.\u003c\/p\u003e\n\u003cp\u003ePerfect for users who already own the SidecarTridge TOS Emulator and want to unlock support for TOS 2.06, EmuTOS 256KB builds, and Mega STe-compatible ROM layouts on a standard Mega ST.\u003c\/p\u003e\n\u003ch2\u003eFeatures\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eFully solderless installation through the Mega ST MEGABUS connector\u003c\/li\u003e\n\u003cli\u003eAdds native 256KB ROM decoding support to Atari Mega ST computers\u003c\/li\u003e\n\u003cli\u003eCompatible with 192KB and 256KB TOS images\u003c\/li\u003e\n\u003cli\u003eEnables support for:\n\u003cul\u003e\n\u003cli\u003eTOS 2.06\u003c\/li\u003e\n\u003cli\u003eSuperTOS\u003c\/li\u003e\n\u003cli\u003eEmuTOS 256KB\u003c\/li\u003e\n\u003cli\u003eMega STe-compatible ROM mappings\u003c\/li\u003e\n\u003cli\u003eWorks with existing SidecarTridge TOS Emulator setups\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/li\u003e\n\u003cli\u003eNo modifications required to original motherboard ROM sockets\u003c\/li\u003e\n\u003cli\u003eCompatible with systems fitted with the Atari Blitter board\u003c\/li\u003e\n\u003cli\u003eTransparent ROM address mapping for maximum software compatibility\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eWhat the Decoder Does\u003c\/h2\u003e\n\u003cp\u003eThe Atari Mega ST was originally designed around smaller ROM configurations and does not natively support later 256KB TOS layouts used by the Mega STe and other enhanced systems.\u003c\/p\u003e\n\u003cp\u003eThe SidecarTridge 256KB Decoder solves this limitation by generating the missing address lines and ROM select logic required by modern 256KB TOS images. Once installed, the Mega ST can access larger ROM layouts exactly as if the machine had native support for them.\u003c\/p\u003e\n\u003cp\u003eThis allows advanced TOS switching and compatibility features while keeping the original machine fully reversible and unmodified.\u003c\/p\u003e\n\u003ch2\u003eInstallation\u003c\/h2\u003e\n\u003cp\u003eInstallation is simple and requires no soldering:\u003c\/p\u003e\n\u003col\u003e\n\u003cli\u003eOpen the Mega ST and expose the MEGABUS connector\u003c\/li\u003e\n\u003cli\u003eInsert the 256KB Decoder into the MEGABUS slot\u003c\/li\u003e\n\u003cli\u003eConnect the included 6-pin flat cable or FFC to the SidecarTridge carrier board\u003c\/li\u003e\n\u003cli\u003eReassemble the system and boot normally\u003c\/li\u003e\n\u003c\/ol\u003e\n\u003cp\u003eThe decoder is designed to coexist with standard Mega ST hardware configurations, including machines equipped with the Atari Blitter expansion.\u003c\/p\u003e\n\u003ch2\u003eCompatibility\u003c\/h2\u003e\n\u003cp\u003eSupported exclusively on Atari Mega ST systems using the SidecarTridge Mega ST carrier boards. \u003c\/p\u003e\n\u003cp\u003eCompatible motherboard revisions include:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eC100167-001 Rev. 4.0\u003c\/li\u003e\n\u003cli\u003eC100167-001 Rev. B\u003c\/li\u003e\n\u003cli\u003eC100167-001 Rev. 5.0\u003c\/li\u003e\n\u003cli\u003eC100501-001\u003c\/li\u003e\n\u003cli\u003eC103277 Rev. 2.2\u003c\/li\u003e\n\u003cli\u003eC103544-001\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003e\u003c\/strong\u003e\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cspan style=\"color: rgb(255, 42, 0);\"\u003e\u003cstrong\u003eWARNING: If you are using a TOS Emulator carrier board revision 2.x or 3.x and your board does not include the IC labeled “MUX” located on the left side of the connectors, please read the \u003ca href=\"https:\/\/docs.sidecartridge.com\/sidecartridge-tos-256kb-decoder\/upgrade-carrier-board\/\" target=\"_blank\" rel=\"noopener\"\u003eUpgrading an older Mega ST carrier board guide \u003c\/a\u003ebefore continuing.\u003c\/strong\u003e\u003c\/span\u003e\u003cbr\u003e\u003c\/p\u003e\n\u003ch2\u003ePackage Contents\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eSidecarTridge 256KB Decoder Board\u003c\/li\u003e\n\u003cli\u003e6-pin flat interconnect cable or 6-pin \u003cmeta charset=\"utf-8\"\u003eFlexible Flat Cable \u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2\u003eRequirements\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eExisting SidecarTridge TOS Emulator setup\u003c\/li\u003e\n\u003cli\u003eAtari Mega ST computer\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e","brand":"SIDECARTRIDGE","offers":[{"title":"For REV 4.0.0","offer_id":53987413229901,"sku":"SDCRT0030","price":14.0,"currency_code":"EUR","in_stock":true},{"title":"For REV from 2.1.0 to 4.0.0","offer_id":53987413262669,"sku":"SDCRT0032","price":14.0,"currency_code":"EUR","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0778\/3746\/7981\/files\/256KB-DECODER-BOARD-MEGABUS-TOP-WITH-CABLE.png?v=1779815989","url":"https:\/\/store.sidecartridge.com\/products\/sidecartridge%c2%ae-256kb-decoder-for-mega-st","provider":"SidecarTridge","version":"1.0","type":"link"}