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+ # iCE40UP5K support 
+
+This board directory builds for the iCE40UP5K in the QFN48 (SG48) package.  iCE40UP5K SG48 is the part used on the [Gnarly Grey UPDuino Mini board](https://gnarlygrey.atspace.cc/development-platform.html). 
+ 
+ ## Peripheral support
+
+So far only UART is tested and supported.  Three bits of the PC monitor bus are mapped to the dedicated LED drivers to give some indication of the currently running code.
+
+VGA is brought out to pins but have not been tested.
+
+PS/2, button, and TM1638 front panel are not supported.
+
+At this time, all ROM and RAM are mapped as block RAM, and arachne-pnr reports that 28/30 BRAMs are utilized.  If larger ROMs or more RAM is needed, RAM should be moved to SPRAM instead.
+
+The on-chip oscillator and PLL are used to generate the 25MHz clock used by the design.
+
+See the .pcf for pin connections.  Note that the iCE40UP5K pin numbers in the .pcf correspond to the UPDuino pin silkscreen labels.
+
+ ## Building
+
+Install a recent IceStorm toolchain, and:
+
+make clean all
+
+ ## Use
+
+Flash using your method of choice.  Attach a 3.3V serial connection to uart_tx (output to PC) and uart_rx (input from PC).  Start a terminal at 115200,n,8,1.
+
+Toggling CRESET_B restarts to the Woz monitor.
+
+The Woz monitor is a simple hex debugger.  To run BASIC, type: "E000R".  Note that both BASIC and the monitor require commands to be input as caps.