- added support to ATMega2560

README.md

@@ -1,26 +1,28 @@
-# VGAX Library for Arduino UNO
+# VGAX Library for Arduino UNO and MEGA
 
 COPYRIGHT (C) 2014 Sandro Maffiodo  
 [[email protected]](mailto:[email protected])  
-[http://www.assezeta.com/sandromaffiodo](http://www.assezeta.com/sandromaffiodo)
+[http://www.sandromaffiodo.com](http://www.sandromaffiodo.com)
 
 ![screenshot0](docs/screenshot3.jpg)
 
 YouTube videos:
 
-[<img width='30%' src='https://i.ytimg.com/vi/PfN_sQffLkg/mqdefault.jpg'/>](https://youtu.be/PfN_sQffLkg)
-[<img width='30%' src='https://i.ytimg.com/vi/Yvdf-pfneA4/mqdefault.jpg'/>](https://youtu.be/Yvdf-pfneA4)
-[<img width='30%' src='https://i.ytimg.com/vi/W9ebehFDDRA/mqdefault.jpg'/>](https://youtu.be/W9ebehFDDRA)
+[<img width='20%' src='https://i.ytimg.com/vi/PfN_sQffLkg/mqdefault.jpg'/>](https://youtu.be/PfN_sQffLkg)
+[<img width='20%' src='https://i.ytimg.com/vi/Yvdf-pfneA4/mqdefault.jpg'/>](https://youtu.be/Yvdf-pfneA4)
+[<img width='20%' src='https://i.ytimg.com/vi/W9ebehFDDRA/mqdefault.jpg'/>](https://youtu.be/W9ebehFDDRA)
+[<img width='20%' src='https://i.ytimg.com/vi/Qs3uyhzUcfA/mqdefault.jpg'/>](https://youtu.be/Qs3uyhzUcfA)
 
 Some photos:
 
 [<img width='20%' src='docs/screenshot1.jpg'/>](docs/screenshot1.jpg)
 [<img width='20%' src='docs/screenshot5.jpg'/>](docs/screenshot5.jpg)
 [<img width='20%' src='docs/screenshot2.jpg'/>](docs/screenshot2.jpg)
+[<img width='20%' src='docs/screenshot6.jpg'/>](docs/screenshot6.jpg)
 
 ## What is VGAX?
 
-This is a VGA library for Arduino UNO.  
+This is a VGA library for Arduino UNO and Arduino MEGA.  
 To use this library you need only 4 resistors and one DSUB15 connector.  
 This library require an ATMega328 MCU (or higher) MCU. Does not work with ATTINY family or ATMega168.
 
@@ -33,13 +35,21 @@ Thanks to Roberto Melzi [RobCai](https://www.youtube.com/channel/UCgQK0QAMUV5L4O
 
 ## Video
 
-The library implement a 120x60px framebuffer where each pixel is stored as 2 bits (4 colors). 
-The framebuffer is stored inside SRAM and require 1800 bytes. Your programs cannot use more than 200 bytes so be carefull! If you want, you can use another Arduino UNO to drive the one that use VGAX library.
+The library implement a 120x60px framebuffer where each pixel is stored as 2 bits (4 colors). On Arduino MEGA resolution can be increased to 120x240px.
+The framebuffer is stored inside SRAM and require at least 1800 bytes. This mean that on ATMega328 your programs cannot use more than 200 bytes so be carefull! If you want, you can use another Arduino UNO to drive the one that use VGAX library. On ATMega2560 you have more SRAM but if you expand the framebuffer to 120x240px free SRAM will be 800 bytes.
 
 VGAX framebuffer use 2bit for each pixel. Inside each byte are stored 4 pixels, packed in this order: leftmost pixel is in the highest 2bits, rightmost pixel is  on the lowest 2bits:
 
 ![framebuffer.png](docs/framebuffer.png)
 
+On Arduino MEGA (ATMega2560) framebuffer can be extended to 120x90px with squared pixels or 120x240px with rectangular pixels. You can enable these alternatives resolutions by uncommenting these constants on VGAX.h header:
+
+	//uncomment ATMEGA2560_HIGHRES to use 120x90px squared pixels
+	//#define ATMEGA2560_HIGHRES 
+
+	//uncomment ATMEGA2560_HIGHRES to use 120x240px rectangular pixels
+	//#define ATMEGA2560_MAXRES
+
 ## Audio
 
 This library implement an async tone (audio) generation too! The audio signal is
@@ -58,11 +68,12 @@ You need:
 Then connect them like the following schema.  
 *NOTE: The DSUB15 connector is shown from rear view*
 
-![wire.png](docs/wire0.png)
+![wire0.png](docs/wire0.png)
+![wire1.png](docs/wire1.png)
 
 ### 4 Colors
 The 4 colors generated from the library are not predefined.  
-You can connect the PIN6 and PIN7 with two of the VGA DSUB15 RGB pins, selecting the color combination that you prefer.
+On Arduino UNO you can connect the pin 6 and pin 7 with two of the VGA DSUB15 RGB pins, selecting the color combination that you prefer.
 
 These are some of the possible combinations, done without additional components:
 
@@ -78,6 +89,7 @@ These are some of the possible combinations, done without additional components:
 
 ![color5.png](docs/color5.png)
 
+Pin 6 and pin 7 on Arduino MEGA must be changed to pin 30 and pin 31 but the same logic of choosing colors can be applyed on MEGA.
 
 ## PIN and PORT
 
@@ -87,6 +99,8 @@ PORTD pins**.
 The vertical synchronization signal is generated on pin 9. Gammon's version use
 the pin 10 but i prefer to keep pins 10 11 12 13 free for common SPI usage.
 
+On Arduino MEGA PORTD is substituted to PORTA, vertical sync is pin 11 and horizontal pin is 9.
+
 ## Interrupt
 
 VGAX library generate the video signal using only interrupts, so, inside main() function, you can do anything you want. Your code will be interrupted when VGA signal needs to be generated.
@@ -97,11 +111,11 @@ VGAX library generate the video signal using only interrupts, so, inside main()
 
 ## Timers
 
-This library uses **all the 3 timers** of ATMega328 MCU.
+This library uses **all the 3 timers** of ATMega328 MCU. On ATMega2560 there are more unused timers.
 
 *TIMER1* and *TIMER2* are configured to generate HSYNC and VSYNC pulses.
 The setup code for these two timers has been [created by Nick Gammon](http://www.gammon.com.au/forum/?id=11608).
-I have only made some modifications to use pin 9 instead of pin 10.
+I have only made some modifications to use pin 9 instead of pin 10. On ATMega2560 HSYNC and VSYNC are different.
 
 *TIMER0* is used to fix the interrupt jitter. I have modified an assembler trick
 originally writen by [Charles CNLOHR](https://github.com/cnlohr/avrcraft/tree/master/terminal).

VGAX.cpp

@@ -1,20 +1,38 @@
 #include "VGAX.h"
 
 //HSYNC pin used by TIMER2
-#define HSYNCPIN 3
+#if defined(__AVR_ATmega2560__)
+  #define HSYNCPIN 9
+#else
+  #define HSYNCPIN 3
+#endif
 
 //These two pin cannot be modified without modify the HSYNC assembler code
-#define COLORPIN0 6
-#define COLORPIN1 7
+#if defined(__AVR_ATmega2560__)
+  #define COLORPIN0 30
+  #define COLORPIN1 31
+#else
+  #define COLORPIN0 6
+  #define COLORPIN1 7
+#endif
 
 //VSYNC pin used by TIMER1. Can be 9 or 10
-#define VSYNCPIN 9
+#if defined(__AVR_ATmega2560__)
+  #define VSYNCPIN 11
+#else
+  #define VSYNCPIN 9
+#endif
 
 //Number of VGA lines to be skipped (black lines)
 /*These lines includes the vertical sync pulse and back porch.
 Minimum value must be 35 (calculate from Nick Gammon)
 You can modify this value to center the framebuffer vertically, or not*/
-#define SKIPLINES 90
+#if defined(__AVR_ATmega2560__) && \
+(defined(ATMEGA2560_HIGHRES) || defined(ATMEGA2560_MAXRES))
+  #define SKIPLINES 32
+#else
+  #define SKIPLINES 90
+#endif
 
 static byte afreq, afreq0;
 unsigned vtimer;
@@ -83,14 +101,19 @@ ISR(TIMER2_OVF_vect) {
     //code from https://github.com/cnlohr/avrcraft/tree/master/terminal
     //modified from 4 nop align to 8 nop align
     #define DEJITTER_OFFSET 1
-    #define DEJITTER_SYNC -3
+    #define DEJITTER_SYNC -2
     asm volatile(
       "     lds r16, %[timer0]    \n\t" //
-      //"   add r16, %[toffset]   \n\t" //
+      #if defined(__AVR_ATmega2560__)
+      "     add r16, %[toffset]   \n\t" //
+      #endif
       "     subi r16, %[tsync]    \n\t" //
       "     andi r16, 7           \n\t" //
       "     call TL               \n\t" //
       "TL:                        \n\t" //
+      #if defined(__AVR_ATmega2560__)
+      "     pop r17               \n\t" //ATMEGA2560 has a 22bit PC!
+      #endif
       "     pop r31               \n\t" //
       "     pop r30               \n\t" //
       "     adiw r30, (LW-TL-5)   \n\t" //
@@ -149,12 +172,21 @@ ISR(TIMER2_OVF_vect) {
       "    ldi r16, 0       \n\t" //
       "    out %[port], r16 \n\t" //write black for next pixels
     :
+    #if defined(__AVR_ATmega2560__)
+    : [port] "I" (_SFR_IO_ADDR(PORTC)),
+    #else
     : [port] "I" (_SFR_IO_ADDR(PORTD)),
+    #endif
       "z" "I" (/*rline*/(byte*)vgaxfb + rlinecnt*VGAX_BWIDTH)
     : "r16", "r17", "r20", "r21", "memory");
 
     //increment framebuffer line counter after 6 VGA lines
-    if (++aline==5) { 
+    #if defined(__AVR_ATmega2560__) && defined(ATMEGA2560_MAXRES)
+      #define CLONED_LINES (2-1)
+    #else
+      #define CLONED_LINES (6-1)
+    #endif
+    if (++aline==CLONED_LINES) { 
       aline=-1;
       rlinecnt++;
     } else {
@@ -179,20 +211,20 @@ void VGAX::begin(bool enableTone) {
   //disable TIMER0 interrupt
   TIMSK0=0;
   TCCR0A=0;
-  TCCR0B=1; //enable 16MHz counter (used to fix the HSYNC interrupt jitter)
+  TCCR0B=(1 << CS00); //enable 16MHz counter (used to fix the HSYNC interrupt jitter)
   OCR0A=0;
   OCR0B=0;
   TCNT0=0;
   //TIMER1 - vertical sync pulses
   pinMode(VSYNCPIN, OUTPUT);
-  #if VSYNCPIN==10
+  #if VSYNCPIN==10 //ATMEGA328 PIN 10
   TCCR1A=bit(WGM10) | bit(WGM11) | bit(COM1B1);
   TCCR1B=bit(WGM12) | bit(WGM13) | bit(CS12) | bit(CS10); //1024 prescaler
   OCR1A=259; //16666 / 64 uS=260 (less one)
   OCR1B=0; //64 / 64 uS=1 (less one)
   TIFR1=bit(TOV1); //clear overflow flag
   TIMSK1=bit(TOIE1); //interrupt on overflow on TIMER1
-  #else
+  #else //ATMEGA328 PIN 9 or ATMEGA2560 PIN 11
   TCCR1A=bit(WGM11) | bit(COM1A1);
   TCCR1B=bit(WGM12) | bit(WGM13) | bit(CS12) | bit(CS10); //1024 prescaler
   ICR1=259; //16666 / 64 uS=260 (less one)
@@ -229,10 +261,7 @@ void VGAX::clear(byte color) {
   c&=3;
   register byte c0=(c*4) | c;
   c0|=c0*16;
-  unsigned cnt=VGAX_BSIZE;
-  byte *o=(byte*)vgaxfb;
-  while (cnt--)
-    *o++=c0;
+  memset(vgaxfb, c0, VGAX_BSIZE);
 }
 void VGAX::copy(byte *src) {
   byte *o=(byte*)vgaxfb;

VGAX.h

@@ -1,12 +1,12 @@
 /*
-VGAX Library for Arduino UNO (ATMega328 MCU)
+VGAX Library for Arduino UNO (ATMega328) and Arduino MEGA (ATMega2560)
 Source code url: https://github.com/smaffer/vgax
 
 120x60px VGA framebuffer with 4 colors
 
 COPYRIGHT (C) 2014 Sandro Maffiodo
 [email protected]
-http://www.assezeta.com/sandromaffiodo
+http://www.sandromaffiodo.com
 
 based on the "VGA color video generation" by Nick Gammon:
   http://www.gammon.com.au/forum/?id=11608.
@@ -28,7 +28,19 @@ HERE you can find some inline documentation about the VGAX library class
 #endif
 #include <avr/pgmspace.h>
 
-#define VGAX_HEIGHT 60 //number of lines
+//uncomment ATMEGA2560_HIGHRES to use 120x90px squared pixels
+//#define ATMEGA2560_HIGHRES 
+
+//uncomment ATMEGA2560_HIGHRES to use 120x240px rectangular pixels
+#define ATMEGA2560_MAXRES
+
+#if defined(ATMEGA2560_MAXRES)
+  #define VGAX_HEIGHT 240 //number of lines
+#elif defined(ATMEGA2560_HIGHRES)
+  #define VGAX_HEIGHT 80 //number of lines
+#else
+  #define VGAX_HEIGHT 60 //number of lines
+#endif
 #define VGAX_BWIDTH 30 //number of bytes in a row
 #define VGAX_WIDTH (VGAX_BWIDTH*4) //number of pixels in a row
 #define VGAX_BSIZE (VGAX_BWIDTH*VGAX_HEIGHT) //size of framebuffer in bytes

VGAXUtils.h

@@ -3,7 +3,7 @@ Utils for VGAX Library
 
 COPYRIGHT (C) 2014 Sandro Maffiodo
 [email protected]
-http://www.assezeta.com/sandromaffiodo
+http://www.sandromaffiodo.com
 
 Some of these methods are from TVOut library created by Myles Metzer (thank you!)
 https://code.google.com/p/arduino-tvout/

blit.cpp

@@ -12,21 +12,14 @@ void VGAX::blit(byte *src, byte swidth, byte sheight, char dx, char dy) {
       byte sw=swidth, sx=0;
       char ldx=dx;
       while (sw--) {
-        /*if ((sx & 3)==0 && (sw & 3)==0) {
-          putpixel4(ldx, dy, pgm_read_byte(srcline + (sx>>2)));
-          sw-=3;
-          sx+=4;
-          ldx+=4;
-        } else*/ {
-          //get sprite pixel
-          byte p=pgm_read_byte(srcline + (sx>>2));
-          byte bitpos=6-(sx & 3)*2;
-          byte spixel=(p >> bitpos);
-          //set framebuffer pixel
-          putpixel(ldx, dy, spixel);
-          sx++;
-          ldx++;
-        }
+        //get sprite pixel
+        byte p=pgm_read_byte(srcline + (sx>>2));
+        byte bitpos=6-(sx & 3)*2;
+        byte spixel=(p >> bitpos);
+        //set framebuffer pixel
+        putpixel(ldx, dy, spixel);
+        sx++;
+        ldx++;
       }
       srcline+=slinesize;
       dy++;

examples/BitFont/BitFont.ino

@@ -118,8 +118,8 @@ void loop() {
   else 
     vga.noTone();
   vga.clear(11);
-  vga.printPROGMEM((byte*)fnt_nanofont_data, FNT_NANOFONT_SYMBOLS_COUNT, FNT_NANOFONT_HEIGHT, 3, 1, str0, x, 10, 1);
-  vga.printPROGMEM((byte*)fnt_nanofont_data, FNT_NANOFONT_SYMBOLS_COUNT, FNT_NANOFONT_HEIGHT, 3, 1, str1, x, 17, 2);
+  vga.printPROGMEM((byte*)fnt_nanofont_data, FNT_NANOFONT_SYMBOLS_COUNT, FNT_NANOFONT_HEIGHT, 3, 1, str0, x, VGAX_HEIGHT/2-3, 1);
+  vga.printPROGMEM((byte*)fnt_nanofont_data, FNT_NANOFONT_SYMBOLS_COUNT, FNT_NANOFONT_HEIGHT, 3, 1, str1, x, VGAX_HEIGHT/2+4, 2);
   x++;
   if (x==VGAX_WIDTH)
     x=-VGAX_WIDTH;