Merge branch 'main' of github.com:dh219/DSTB into main

README.md

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+## David's ST Booster (DSTB)
+
+#### A low-cost DIY 16MHz 68000 accelerator with 8MB fast AltRAM and optional ROM cacheing
+
+Fitting into a small footprint, just 3mm wider than the 68000 socket into which this plugs, the board (\~$4) contains one XC95144XL-100 CPLD (\~$5), one 32Mbit TSSOP-II-54 SDRAM chip (~$5), two level-shifting buffers (\~$6), one 5 or 3.3V 66MHz oscillator in a 7x5mm package (\~$4) and a 3.3V LDO voltage regulator (\~$2) as the core components.
+
+This provides all the interface between the ST and a 16MHz capable 68000. The 68000 will run at the oscillator frequency divided by four, so 16.5MHz in normal configuration.
+
+The AltRAM runs at at full speed for a 16MHz processor, offering throughput of around 7.7MB/s compared to ST-RAM's 3.7MB/s.
+
+Firmware source (ISE), board design files (KiCAD) and any source for support programs will be published at each release.
+
+#### Cost & requirements
+
+I anticipate a single board can be hand assembled for approximately 30USD. You may need to acquire a 16MHz capable DIP-64 68000 to pair with it if your old 8MHz chip cannot handle the faster clock.
+
+#### Manual
+
+At the moment, there is no manual. This will be written in due course.
+
+There is a build video available at https://youtu.be/VHx3kat0Q6M
+
+#### Software
+
+See https://github.com/dh219/DSTB-tools for the 'AltRAM' or 'AltROM' programs (NB. this board is not compatible with 'ExxosRAM.PRG').
+
+EmuTOS automatically recognises and activate AltRAM.
+
+---
+
+*Copyright 2022 D Henderson, released under GPL2.0*