''******************************************** ''* VGA 512x384 2-Color Bitmap Driver v1.0 * ''* Author: Chip Gracey * ''* Copyright (c) 2006 Parallax, Inc. * ''* See end of file for terms of use. * ''******************************************** '' '' This object generates a 512x384 pixel bitmap, signaled as 1024x768 VGA. '' Each pixel is one bit, so the entire bitmap requires 512 x 384 / 32 longs, '' or 6,144 longs (24KB). Color words comprised of two byte fields provide '' unique colors for every 32x32 pixel group. These color words require 512/32 '' * 384/32 words, or 192 words. Pixel memory and color memory are arranged '' left-to-right then top-to-bottom. '' '' A sync indicator signals each time the screen is drawn (you may ignore). '' '' You must provide buffers for the colors, pixels, and sync. Once started, '' all interfacing is done via memory. To this object, all buffers are read- '' only, with the exception of the sync indicator which gets written with a '' non-0 value. You may freely write all buffers to affect screen appearance. '' CON ' 512x384 settings - signals as 1024 x 768 @ 67Hz hp = 512 'horizontal pixels vp = 384 'vertical pixels hf = 8 'horizontal front porch pixels hs = 48 'horizontal sync pixels hb = 88 'horizontal back porch pixels vf = 1 'vertical front porch lines vs = 3 'vertical sync lines vb = 28 'vertical back porch lines hn = 1 'horizontal normal sync state (0|1) vn = 1 'vertical normal sync state (0|1) pr = 35 'pixel rate in MHz at 80MHz system clock (5MHz granularity) ' Tiles xtiles = hp / 32 ytiles = vp / 32 ' H/V inactive states hv_inactive = (hn << 1 + vn) * $0101 VAR long cog PUB start(BasePin, ColorPtr, PixelPtr, SyncPtr) : okay | i, j '' Start VGA driver - starts a COG '' returns false if no COG available '' '' BasePin = VGA starting pin (0, 8, 16, 24, etc.) '' '' ColorPtr = Pointer to 192 words which define the "0" and "1" colors for '' each 32x32 pixel group. The lower byte of each word contains '' the "0" bit RGB data while the upper byte of each word contains '' the "1" bit RGB data for the associated group. The RGB '' data in each byte is arranged as %RRGGBB00 (4 levels each). '' '' color word example: %%0020_3300 = "0" = gold, "1" = blue '' '' PixelPtr = Pointer to 6,144 longs containing pixels that make up the 512 x '' 384 pixel bitmap. Longs' LSBs appear left on the screen, while '' MSBs appear right. The longs are arranged in sequence from left- '' to-right, then top-to-bottom. '' '' SyncPtr = Pointer to long which gets written with non-0 upon each screen '' refresh. May be used to time writes/scrolls, so that chopiness '' can be avoided. You must clear it each time if you want to see '' it re-trigger. 'if driver is already running, stop it stop 'implant pin settings and pointers, then launch COG reg_vcfg := $200000FF + (BasePin & %111000) << 6 i := $FF << (BasePin & %011000) j := BasePin & %100000 == 0 reg_dira := i & j reg_dirb := i & !j longmove(@color_base, @ColorPtr, 2) if (cog := cognew(@init, SyncPtr) + 1) return true PUB stop | i '' Stop VGA driver - frees a COG if cog cogstop(cog~ - 1) DAT '*********************************************** '* Assembly language VGA 2-color bitmap driver * '*********************************************** org 'set origin to $000 for start of program ' Initialization code - init I/O init mov dira,reg_dira 'set pin directions mov dirb,reg_dirb movi ctra,#%00001_101 'enable PLL in ctra (VCO runs at 4x) movi frqa,#(pr / 5) << 3 'set pixel rate mov vcfg,reg_vcfg 'set video configuration ' Main loop, display field and do invisible sync lines field mov color_ptr,color_base 'reset color pointer mov pixel_ptr,pixel_base 'reset pixel pointer mov y,#ytiles 'set y tiles :ytile mov yl,#32 'set y lines per tile :yline mov yx,#2 'set y expansion :yexpand mov x,#xtiles 'set x tiles mov vscl,vscl_pixel 'set pixel vscl :xtile rdword color,color_ptr 'get color word and color,colormask 'clear h/v bits or color,hv 'set h/v inactive states rdlong pixel,pixel_ptr 'get pixel long waitvid color,pixel 'pass colors and pixels to video add color_ptr,#2 'point to next color word add pixel_ptr,#4 'point to next pixel long djnz x,#:xtile 'another x tile? sub color_ptr,#xtiles * 2 'repoint to first colors in same line sub pixel_ptr,#xtiles * 4 'repoint to first pixels in same line mov x,#1 'do horizontal sync call #hsync djnz yx,#:yexpand 'y expand? add pixel_ptr,#xtiles * 4 'point to first pixels in next line djnz yl,#:yline 'another y line in same tile? add color_ptr,#xtiles * 2 'point to first colors in next tile djnz y,#:ytile 'another y tile? wrlong colormask,par 'visible done, write non-0 to sync mov x,#vf 'do vertical front porch lines call #blank mov x,#vs 'do vertical sync lines call #vsync mov x,#vb 'do vertical back porch lines call #vsync jmp #field 'field done, loop ' Subroutine - do blank lines vsync xor hvsync,#$101 'flip vertical sync bits blank mov vscl,hvis 'do blank pixels waitvid hvsync,#0 hsync mov vscl,#hf 'do horizontal front porch pixels waitvid hvsync,#0 mov vscl,#hs 'do horizontal sync pixels waitvid hvsync,#1 mov vscl,#hb 'do horizontal back porch pixels waitvid hvsync,#0 djnz x,#blank 'another line? hsync_ret blank_ret vsync_ret ret ' Data reg_dira long 0 'set at runtime reg_dirb long 0 'set at runtime reg_vcfg long 0 'set at runtime color_base long 0 'set at runtime (2 contiguous longs) pixel_base long 0 'set at runtime vscl_pixel long 1 << 12 + 32 '1 pixel per clock and 32 pixels per set colormask long $FCFC 'mask to isolate R,G,B bits from H,V hvis long hp 'visible pixels per scan line hv long hv_inactive '-H,-V states hvsync long hv_inactive ^ $200 '+/-H,-V states ' Uninitialized data color_ptr res 1 pixel_ptr res 1 color res 1 pixel res 1 x res 1 y res 1 yl res 1 yx res 1 {{ ┌──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┐ │ TERMS OF USE: MIT License │ ├──────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────────┤ │Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation │ │files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, │ │modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software│ │is furnished to do so, subject to the following conditions: │ │ │ │The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.│ │ │ │THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE │ │WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 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