Merge pull request #39 from markadev/abaffa-videx-compatibility-mode

Integrate in "Videx compatibility" from abaffa's changes

README.md

@@ -25,6 +25,7 @@ These features are currently supported:
    (thanks to @dkgrizzly and @Paco1979)
  * Soft-monochrome mode to force display as if on a monochrome monitor
  * Some Video-7 RGB card extended graphical modes are implemented
+ * Compatibility with Videx VideoTerm modes on Apple II+ (thanks to @abaffa)
 
 I had these goals in mind during design:
  * Generate video out to a more modern display - I don't have any old CRTs for
@@ -94,8 +95,22 @@ a cheap composite -> HDMI adapter
 **DHires**
 ![DHires Mode](docs/composite_vs_vga_dhires.jpg)
 
-**80 Columms**
-![80 Columms Mode](docs/composite_vs_vga_80columms.jpg)
+**80 Columns**
+![80 Columns Mode](docs/composite_vs_vga_80columms.jpg)
+
+
+## 80 Column support for the Apple II+
+
+The firmware implements Videx VideoTerm compatibility when there's a VideoTerm card installed
+in slot 3. It's not enabled by default but if you have a Videx VideoTerm card in slot 3
+then you can enable 80 column VGA support using the Configuration Disk image. The VGA card
+can still be installed in any slot.
+
+**Apple II+ running 80 Columns Examples**
+
+![AppleII 80 Columms Mode 1](docs/apple2plus_videx_80columns1.jpg)
+![AppleII 80 Columms Mode 2](docs/apple2plus_videx_80columns2.jpg)
+![AppleII 80 Columms Mode 3](docs/apple2plus_videx_80columns3.jpg)
 
 
 ## Future work

config-disk/STARTUP.bas

@@ -12,9 +12,11 @@
  130  PRINT "1  SCANLINES  ON      2  SCANLINES  OFF"
  140  PRINT "3  MONOCHROME ON      4  MONOCHROME OFF"
  150  PRINT "5  MONOCHROME CFG     6  CHARSET CFG"
- 170  PRINT "7  COLOR PATTERNS": PRINT ""
- 180  PRINT "11 ABOUT": PRINT "12 LOAD DEFAULT CONFIG"
- 180  PRINT "13 QUIT W/OUT SAVING": PRINT"14 SAVE AND QUIT": PRINT ""
+ 160  PRINT "7  ][+ VIDEX ON       8  ][+ VIDEX OFF"
+ 170  PRINT "9  COLOR PATTERNS": PRINT ""
+ 175  PRINT "11 ABOUT"
+ 180  PRINT "12 LOAD DEFAULT CONFIG": PRINT "13 LOAD SAVED CONFIG"
+ 185  PRINT "14 SAVE AND QUIT": PRINT "15 QUIT W/OUT SAVING"
  190  VTAB 22: GOSUB 1400: INPUT "PLEASE ENTER YOUR SELECTION: ";CH
  200  IF CH < 1 THEN  GOSUB 1550
  210  IF CH = 1 THEN  GOSUB 500
@@ -23,14 +25,15 @@
  240  IF CH = 4 THEN  GOSUB 650
  250  IF CH = 5 THEN  GOSUB 2000
  260  IF CH = 6 THEN  GOSUB 3000
- 270  IF CH = 7 THEN  GOSUB 700
- 280  IF CH = 8 THEN  GOSUB 1550
- 290  IF CH = 9 THEN  GOSUB 1550
+ 270  IF CH = 7 THEN  GOSUB 900
+ 280  IF CH = 8 THEN  GOSUB 950
+ 290  IF CH = 9 THEN  GOSUB 700
  300  IF CH = 10 THEN  GOSUB 1550
  310  IF CH = 11 THEN  GOSUB 1650
  320  IF CH = 12 THEN  GOSUB 800
- 330  IF CH = 13 THEN  GOTO 4050
- 340  IF CH = 14 THEN  GOTO 4000
+ 325  IF CH = 13 THEN  GOSUB 850
+ 330  IF CH = 14 THEN  GOTO 4000
+ 340  IF CH = 15 THEN  GOTO 4050
  350  IF CH > 14 THEN  GOSUB 1550
  360  GOTO 100
  500  REM  '''SCANLINES ON
@@ -46,7 +49,13 @@
  720  FOR I = 0 TO 31: COLOR= I / 2: VLIN 0,39 AT I: NEXT I: FOR I = 0 TO 14 STEP 2: PRINT  TAB( I * 2 + 1);I;: NEXT I: PRINT : FOR I = 1 TO 15 STEP 2: PRINT  TAB( I * 2 + 1);I;: NEXT I
  730  PRINT "": GET A$: TEXT : RETURN 
  800  REM  '''LOAD DEFAULT CONFIGURATION
- 810  POKE BASEADDR + 4,1: RETURN
+ 810  POKE BASEADDR + 4,0: RETURN
+ 850  REM '''LOAD SAVED CONFIGURATION
+ 860  POKE BASEADDR + 4,1: RETURN
+ 900  REM '''][+ VIDEX ON
+ 910  POKE BASEADDR + 0,4: RETURN
+ 950  REM '''][+ VIDEX OFF
+ 910  POKE BASEADDR + 0,8: RETURN
  1400  REM  STRING ROUTINES
  1410  PRINT "---------------------------------------": RETURN 
  1450  HOME : PRINT "APPLE II VGA": GOSUB 1400: PRINT "COPYRIGHT (C) 2021-2023 MARK AIKENS": PRINT "COPYRIGHT (C) 2022-2023 DAVID KUDER": RETURN 

docs/Usage.md

@@ -4,6 +4,9 @@ After you load on the firmware for your respective Apple II system (II+ or IIe)
 the VGA card is generally plug-and-play. Plug it in, power on your Apple II
 and that's it.
 
+There are some optional features and other controls that can be changed using the
+menu-based Configuration disk or by directly using `POKE` commands.
+
 
 ## Soft Monochrome Mode
 
@@ -56,7 +59,9 @@ This register controls enablement of some features of the card
 
 | bit(s) | Description
 | ------ | -----------
-|  7:2   | reserved
+|  7:4   | reserved
+|   3    | Setting to 1 will disable Videx VideoTerm support (II+ only)
+|   2    | Setting to 1 will enable Videx VideoTerm support (II+ only)
 |   1    | Setting to 1 will disable simulated scanline rendering
 |   0    | Setting to 1 will enable simulated scanline rendering
 

pico/CMakeLists.txt

@@ -39,6 +39,7 @@ target_sources(applevga PUBLIC
     render_text.c
     ${TEXTFONT_SRC_FILES}
     vga.c
+    videx_vterm.c
 )
 target_include_directories(applevga PUBLIC ${CMAKE_CURRENT_SOURCE_DIR})
 target_link_libraries(applevga PUBLIC

pico/abus.c

@@ -6,6 +6,9 @@
 #include "buffers.h"
 #include "colors.h"
 #include "device_regs.h"
+#ifdef APPLE_MODEL_IIPLUS
+#include "videx_vterm.h"
+#endif
 
 
 #if CONFIG_PIN_APPLEBUS_PHI0 != PHI0_GPIO
@@ -21,7 +24,7 @@ typedef void (*shadow_handler)(bool is_write, uint_fast16_t address, uint_fast8_
 
 
 static int reset_detect_state = 0;
-static shadow_handler softsw_handlers[128];
+static shadow_handler softsw_handlers[256];
 
 
 static void abus_main_setup(PIO pio, uint sm) {
@@ -159,6 +162,18 @@ static void shadow_softsw_57(bool is_write, uint_fast16_t address, uint_fast8_t
     soft_switches |= SOFTSW_HIRES_MODE;
 }
 
+static void shadow_softsw_58(bool is_write, uint_fast16_t address, uint_fast8_t data) {
+#ifdef APPLE_MODEL_IIPLUS
+    videx_vterm_80col_enabled = false;
+#endif
+}
+
+static void shadow_softsw_59(bool is_write, uint_fast16_t address, uint_fast8_t data) {
+#ifdef APPLE_MODEL_IIPLUS
+    videx_vterm_80col_enabled = true;
+#endif
+}
+
 static void shadow_softsw_5e(bool is_write, uint_fast16_t address, uint_fast8_t data) {
     soft_dhires = true;
 }
@@ -181,6 +196,10 @@ void abus_init() {
     // Init states
     soft_switches = SOFTSW_TEXT_MODE;
 
+#ifdef APPLE_MODEL_IIPLUS
+    videx_vterm_init();
+#endif
+
     // Setup soft-switch handlers for the Apple model
     softsw_handlers[0x21] = shadow_softsw_21;
     softsw_handlers[0x50] = shadow_softsw_50;
@@ -191,6 +210,8 @@ void abus_init() {
     softsw_handlers[0x55] = shadow_softsw_55;
     softsw_handlers[0x56] = shadow_softsw_56;
     softsw_handlers[0x57] = shadow_softsw_57;
+    softsw_handlers[0x58] = shadow_softsw_58;
+    softsw_handlers[0x59] = shadow_softsw_59;
 #ifdef APPLE_MODEL_IIE
     softsw_handlers[0x00] = shadow_softsw_00;
     softsw_handlers[0x01] = shadow_softsw_01;
@@ -203,6 +224,12 @@ void abus_init() {
     softsw_handlers[0x5e] = shadow_softsw_5e;
     softsw_handlers[0x5f] = shadow_softsw_5f;
 #endif
+#ifdef APPLE_MODEL_IIPLUS
+    // slot 3 device registers
+    for(uint i = 0xb0; i < 0xc0; i++) {
+        softsw_handlers[i] = videx_vterm_shadow_register;
+    }
+#endif
 
     abus_main_setup(CONFIG_ABUS_PIO, ABUS_MAIN_SM);
 
@@ -273,13 +300,28 @@ static void shadow_memory(bool is_write, uint_fast16_t address, uint32_t value)
     case 0xc000 >> 10:
         reset_detect_state = 0;
 
-        // Handle shadowing of the soft switches in the range 0xc000 - 0xc07f
-        if(address < 0xc080) {
-            shadow_handler h = softsw_handlers[address & 0x7f];
+        // Handle shadowing of the soft switches and I/O in the range $C000 - $C0FF
+        if(address < 0xc100) {
+            shadow_handler h = softsw_handlers[address & 0xff];
             if(h) {
                 h(is_write, address, value & 0xff);
             }
         }
+#ifdef APPLE_MODEL_IIPLUS
+        else if((address >= 0xc300) && (address < 0xc400)) {
+            // slot 3 access
+            videx_vterm_mem_selected = true;
+        }
+#endif
+        break;
+
+    case 0xc800 >> 10:
+    case 0xcc00 >> 10:
+        // expansion slot memory space $C800-$CFFF
+        reset_detect_state = 0;
+#ifdef APPLE_MODEL_IIPLUS
+        videx_vterm_shadow_c8xx(is_write, address, value);
+#endif
         break;
 
     case 0x0000 >> 10:
@@ -305,6 +347,9 @@ static void shadow_memory(bool is_write, uint_fast16_t address, uint32_t value)
             soft_80store = false;
             soft_altcharset = false;
             soft_ramwrt = false;
+#ifdef APPLE_MODEL_IIPLUS
+            videx_vterm_80col_enabled = false;
+#endif
 
             reset_detect_state = 0;
         } else {

pico/config.c

@@ -7,6 +7,9 @@
 #include "buffers.h"
 #include "colors.h"
 #include "textfont/textfont.h"
+#ifdef APPLE_MODEL_IIPLUS
+#include "videx_vterm.h"
+#endif
 
 
 // A block of flash is reserved for storing configuration persistently across power cycles
@@ -32,11 +35,18 @@ struct config {
 
     // magic word determines if the stored configuration is valid
     uint32_t magic_word;
+
+    // Add new fields after here. When reading the config use the IS_STORED_IN_CONFIG macro
+    // to determine if the field you're looking for is actually present in the stored config.
+
+    uint8_t videx_vterm_enabled;
 };
 
 // This is a compile-time check to ensure the size of the config struct fits within one flash erase sector
 typedef char config_struct_size_check[(sizeof(struct config) <= FLASH_SECTOR_SIZE) - 1];
 
+#define IS_STORED_IN_CONFIG(cfg, field) ((offsetof(struct config, field) + sizeof((cfg)->field)) <= (cfg)->size)
+
 
 extern uint8_t __persistent_data_start[];
 static struct config *cfg = (struct config *)__persistent_data_start;
@@ -54,6 +64,14 @@ void config_load() {
     mono_bg_color = cfg->mono_bg_color;
     mono_fg_color = cfg->mono_fg_color;
     memcpy(character_rom, cfg->character_rom, CHARACTER_ROM_SIZE);
+
+#ifdef APPLE_MODEL_IIPLUS
+    if(IS_STORED_IN_CONFIG(cfg, videx_vterm_enabled) && cfg->videx_vterm_enabled) {
+        videx_vterm_enable();
+    } else {
+        videx_vterm_disable();
+    }
+#endif
 }
 
 
@@ -63,6 +81,9 @@ void config_load_defaults() {
     mono_bg_color = mono_bg_colors[1];
     mono_fg_color = mono_fg_colors[1];
     memcpy(character_rom, default_character_rom, CHARACTER_ROM_SIZE);
+#ifdef APPLE_MODEL_IIPLUS
+    videx_vterm_disable();
+#endif
 }
 
 
@@ -71,6 +92,7 @@ void config_save() {
     const int new_config_size = (sizeof(struct config) + FLASH_PAGE_SIZE - 1) & -FLASH_PAGE_SIZE;
     struct config *new_config = malloc(new_config_size);
     memset(new_config, 0xff, new_config_size);
+    memset(new_config, 0, sizeof(struct config));
 
     new_config->size = sizeof(struct config);
     new_config->scanline_emulation = soft_scanline_emulation;
@@ -79,6 +101,9 @@ void config_save() {
     new_config->mono_fg_color = mono_fg_color;
     memcpy(new_config->character_rom, character_rom, CHARACTER_ROM_SIZE);
     new_config->magic_word = MAGIC_WORD_VALUE;
+#ifdef APPLE_MODEL_IIPLUS
+    new_config->videx_vterm_enabled = videx_vterm_enabled;
+#endif
 
     const uint32_t flash_offset = (uint32_t)cfg - XIP_BASE;
     flash_range_erase(flash_offset, FLASH_SECTOR_SIZE);

pico/device_regs.c

@@ -5,6 +5,9 @@
 #include "colors.h"
 #include "config.h"
 #include "textfont/textfont.h"
+#ifdef APPLE_MODEL_IIPLUS
+#include "videx_vterm.h"
+#endif
 
 
 static unsigned int char_write_offset;
@@ -18,6 +21,12 @@ void device_write(uint_fast8_t reg, uint_fast8_t data) {
             soft_scanline_emulation = true;
         if(data & 0x02)
             soft_scanline_emulation = false;
+#ifdef APPLE_MODEL_IIPLUS
+        if(data & 0x04)
+            videx_vterm_enable();
+        if(data & 0x08)
+            videx_vterm_disable();
+#endif
         break;
 
     // soft-monochrome color setting
@@ -55,7 +64,7 @@ void device_write(uint_fast8_t reg, uint_fast8_t data) {
 // command value.
 //
 // Note: some of these commands could take a long time (relative to 6502 bus cycles) so
-// some bus activity may be missed. Other projects like the Analog-V2 delegate this execution
+// some bus activity may be missed. Other projects like the V2-Analog delegate this execution
 // to the other (VGA) core to avoid this. Maybe do this if the missed bus cycles become a noticable
 // issue; I only expect it would happen when some config is being saved, which is not done often.
 void execute_device_command(uint_fast8_t cmd) {

pico/render.c

@@ -1,5 +1,8 @@
 #include "render.h"
 #include "buffers.h"
+#ifdef APPLE_MODEL_IIPLUS
+#include "videx_vterm.h"
+#endif
 
 
 void render_init() {
@@ -8,11 +11,16 @@ void render_init() {
 
 
 void render_loop() {
-    while(1) {
 #ifdef RENDER_TEST_PATTERN
+    while(1) {
         render_vga_testpattern();
+    }
 #else
+    while(1) {
         update_text_flasher();
+#ifdef APPLE_MODEL_IIPLUS
+        videx_vterm_update_flasher();
+#endif
 
         switch(soft_switches & SOFTSW_MODE_MASK) {
         case 0:
@@ -28,9 +36,16 @@ void render_loop() {
             render_hires(true);
             break;
         default:
-            render_text();
+#ifdef APPLE_MODEL_IIPLUS
+            if(videx_vterm_enabled && videx_vterm_80col_enabled) {
+                render_videx_text();
+            } else
+#endif
+            {
+                render_text();
+            }
             break;
         }
-#endif
     }
+#endif
 }