Better cursor key support

README.md

@@ -51,6 +51,9 @@ SN loads the current snapshot, SN- load the previous snapshot and SN+ loads the
 These are the mappings with the numeric shift on:<br/>
 <img src="docs/retro_vga_keyboard_num.svg" width="500"/><br/>
 
+Alt+V sets the arrow keys to behave like a Kempston joystick,
+Alt+C sets the arrow keys to operate the Spectrum cursor keys.
+
 ### RetroVGA kiosk mode
 Kiosk mode disables the menu system and quick-save buttons. 
 Kiosk mode is enabled by placing the following file on the SD-card:

src/ZxSpectrumHidKeyboard.cpp

@@ -66,7 +66,11 @@ ZxSpectrumHidKey KEYS[] = {
   { HID_KEY_B,           1, { {7, 4} }},
   
   { HID_KEY_BACKSPACE,   2, { {0, 0}, {4, 0} }},
-
+  
+  { HID_KEY_ARROW_LEFT,  2, { {0, 0}, {3, 4} }},
+  { HID_KEY_ARROW_DOWN,  2, { {0, 0}, {4, 4} }},
+  { HID_KEY_ARROW_UP,    2, { {0, 0}, {4, 3} }},
+  { HID_KEY_ARROW_RIGHT, 2, { {0, 0}, {4, 2} }}
 };
 
 static bool KEYS_SORTED  = false;

src/picomputer/pzx_keyscan.cpp

@@ -38,8 +38,8 @@ static uint8_t rdb[6];                           // Debounced pins
 static hid_keyboard_report_t hr[2];              // Current and previous hid report
 static uint8_t hri = 0;                          // Currenct hid report index
 static uint8_t kbi = 0;
-static uint8_t kbits[3][6][6] = { 
-  // Normal mappings
+static uint8_t kbits[5][6][6] = { 
+  // Normal mappings + cursor joystick
   {
     // Row 0
     { HID_KEY_SPACE, HID_KEY_ALT_RIGHT, HID_KEY_M, HID_KEY_N, HID_KEY_B, HID_KEY_ARROW_DOWN },
@@ -54,7 +54,37 @@ static uint8_t kbits[3][6][6] = {
     // Row 5
     { HID_KEY_Q, HID_KEY_W, HID_KEY_E, HID_KEY_R, HID_KEY_T, /* HID_KEY_ALT_LEFT */ 0}
   },
-  // Numeric mappings
+  // Normal mappings + kempston joystick
+  {
+    // Row 0
+    { HID_KEY_SPACE, HID_KEY_ALT_RIGHT, HID_KEY_M, HID_KEY_N, HID_KEY_B, 0 },
+    // Row 1
+    { HID_KEY_ENTER, HID_KEY_L, HID_KEY_K, HID_KEY_J, HID_KEY_H, 0 },
+    // Row 2
+    { HID_KEY_P, HID_KEY_O, HID_KEY_I, HID_KEY_U, HID_KEY_Y, 0 },
+    // Row 3
+    { HID_KEY_BACKSPACE, HID_KEY_Z, HID_KEY_X, HID_KEY_C, HID_KEY_V, 0 },
+    // Row 4
+    { HID_KEY_A, HID_KEY_S, HID_KEY_D, HID_KEY_F, HID_KEY_G, HID_KEY_ESCAPE },
+    // Row 5
+    { HID_KEY_Q, HID_KEY_W, HID_KEY_E, HID_KEY_R, HID_KEY_T, /* HID_KEY_ALT_LEFT */ 0}
+  },
+  // Numeric mappings + cursor joystick
+  {
+    // Row 0
+    { HID_KEY_SPACE, HID_KEY_ALT_RIGHT, HID_KEY_SEMICOLON, HID_KEY_MINUS, HID_KEY_EQUAL, 0 },
+    // Row 1
+    { HID_KEY_ENTER, HID_KEY_BRACKET_RIGHT, HID_KEY_BRACKET_LEFT, HID_KEY_GRAVE, HID_KEY_BACKSLASH, 0 },
+    // Row 2
+    { HID_KEY_0, HID_KEY_9, HID_KEY_8, HID_KEY_7, HID_KEY_6, 0 },
+    // Row 3
+    { HID_KEY_BACKSPACE, HID_KEY_COMMA, HID_KEY_PERIOD, HID_KEY_SLASH, HID_KEY_APOSTROPHE, 0 },
+    // Row 4
+    { HID_KEY_A, HID_KEY_S, HID_KEY_D, HID_KEY_F, HID_KEY_G, HID_KEY_ESCAPE },
+    // Row 5
+    { HID_KEY_1, HID_KEY_2, HID_KEY_3, HID_KEY_4, HID_KEY_5, /* HID_KEY_ALT_LEFT */ 0 }
+  },
+  // Numeric mappings + kempston joystick
   {
     // Row 0
     { HID_KEY_SPACE, HID_KEY_ALT_RIGHT, HID_KEY_SEMICOLON, HID_KEY_MINUS, HID_KEY_EQUAL, HID_KEY_ARROW_DOWN },
@@ -78,7 +108,7 @@ static uint8_t kbits[3][6][6] = {
     // Row 2 (Quick save 1-5)
     { HID_KEY_F5, HID_KEY_F4, HID_KEY_F3, HID_KEY_F2, HID_KEY_F1, 0 },
     // Row 3
-    { 0, 0, 0, 0, 0, 0 },
+    { 0, 0, 0, /* cursor mode (C) */ 0, /* joystick mode (V) */ 0, 0 },
     // Row 4
     { HID_KEY_F8, HID_KEY_F9, HID_KEY_F10, 0, 0, 0 },
     // Row 5 (Menu, 0, ZX Symbol)
@@ -150,13 +180,16 @@ void __not_in_flash_func(pzx_keyscan_row)() {
   rdb[ri] = (am | rdb[ri]) & om; 
 }
 
+static uint8_t kempstonJoystick = 0;
+
 uint8_t __not_in_flash_func(pzx_kempston)() {
-  return 
+  return kempstonJoystick ?
     ((rdb[KEY_ESC_ROW] & KEY_ESC_BIT) >> 1)      // Kempston fire
   | ((rdb[KEY_UP_ROW] & KEY_UP_BIT) >> 2)        // Kempston up
   | ((rdb[KEY_DOWN_ROW] & KEY_DOWN_BIT) >> 3)    // Kempston down
   | ((rdb[KEY_LEFT_ROW] & KEY_LEFT_BIT) >> 4)    // Kempston left
-  | ((rdb[KEY_RIGHT_ROW] & KEY_RIGHT_BIT) >> 5); // Kempston right
+  | ((rdb[KEY_RIGHT_ROW] & KEY_RIGHT_BIT) >> 5): // Kempston right
+  0;
 }
 
 void __not_in_flash_func(pzx_keyscan_get_hid_reports)(hid_keyboard_report_t const **curr, hid_keyboard_report_t const **prev) {
@@ -177,16 +210,27 @@ void __not_in_flash_func(pzx_keyscan_get_hid_reports)(hid_keyboard_report_t cons
     }
     if (rdb[KEY_RIGHT_ROW] & KEY_RIGHT_BIT) {
       // Numeric keyboard on
-      kbi = 1;
+      kbi = 2 + kempstonJoystick;
     }
     else if (rdb[KEY_LEFT_ROW] & KEY_LEFT_BIT) {
       // Numeric keyboard off
-      kbi = 0;
+      kbi = 0 + kempstonJoystick;
     }
+    if (rdb[3] & (1<<3)) {
+      // Cursor mode
+      kempstonJoystick = 0;
+      kbi &= ~1;
+    }
+    else if (rdb[3] & (1<<4)) {
+      // Joystick mode
+      kempstonJoystick = 1;
+      kbi |= 1;
+    }    
     rdb[KEY_UP_ROW] &= ~KEY_UP_BIT;
     rdb[KEY_DOWN_ROW] &= ~KEY_DOWN_BIT;
     rdb[KEY_RIGHT_ROW] &= ~KEY_RIGHT_BIT;
     rdb[KEY_LEFT_ROW] &= ~KEY_LEFT_BIT;
+    rdb[3] &= ~((1<<3) | (1<<4));
   }
   
   // Build the current hid report
@@ -206,7 +250,7 @@ void __not_in_flash_func(pzx_keyscan_get_hid_reports)(hid_keyboard_report_t cons
           while(ki < sizeof(chr->keycode)) chr->keycode[ki++] = 1;
           break;  
         }
-        uint8_t kc = kbits[alt_down ? 2 : kbi][ri][ci];
+        uint8_t kc = kbits[alt_down ? 4 : kbi][ri][ci];
         if (kc) chr->keycode[ki++] = kc;
       }
       ++ci;