First upload. Untested software

2026-04-08 17:02:29 +02:00
commit 9b83763318
11 changed files with 698 additions and 0 deletions
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+/* Baremetal Risc-V USB <=> Amiga Joystick/Mouse HID converter. 
+ * March 2026 - Anders Holck
+ * This software has no license. If you choose to use, please include my name :)
+*/
+
+#include "amiga_hw.h"
+#include "usb_dwc2.h"
+
+#define GPIOA_EXT_PORTA 0x03020050
+
+// GPIOA Bit Mappings (From PINS.md)
+#define BIT_JOY1_FIRE  28
+#define BIT_JOY1_UP    29
+#define BIT_JOY1_DOWN  14
+#define BIT_JOY1_LEFT  15
+#define BIT_JOY1_RIGHT 16
+
+#define BIT_JOY2_FIRE  17
+#define BIT_JOY2_UP    18
+#define BIT_JOY2_DOWN  19
+#define BIT_JOY2_LEFT  20
+#define BIT_JOY2_RIGHT 21
+
+#define BIT_MOUSE_H_P  22
+#define BIT_MOUSE_V_P  23
+#define BIT_MOUSE_H_D  24
+#define BIT_MOUSE_V_D  25
+#define BIT_MOUSE_BT1  26
+#define BIT_MOUSE_BT2  27
+
+static uint8_t last_h_pulse = 0;
+static uint8_t last_v_pulse = 0;
+
+void amiga_hw_poll(amiga_input_t *input) {
+    uint32_t val = read32(GPIOA_EXT_PORTA);
+
+    // 1. Joystick 1 (Active Low - Amiga pulls to GND)
+    input->joy1 = 0;
+    if (!(val & (1 << BIT_JOY1_UP)))    input->joy1 |= (1 << 0);
+    if (!(val & (1 << BIT_JOY1_DOWN)))  input->joy1 |= (1 << 1);
+    if (!(val & (1 << BIT_JOY1_LEFT)))  input->joy1 |= (1 << 2);
+    if (!(val & (1 << BIT_JOY1_RIGHT))) input->joy1 |= (1 << 3);
+    if (!(val & (1 << BIT_JOY1_FIRE)))  input->joy1 |= (1 << 4);
+
+    // 2. Joystick 2
+    input->joy2 = 0;
+    if (!(val & (1 << BIT_JOY2_UP)))    input->joy2 |= (1 << 0);
+    if (!(val & (1 << BIT_JOY2_DOWN)))  input->joy2 |= (1 << 1);
+    if (!(val & (1 << BIT_JOY2_LEFT)))  input->joy2 |= (1 << 2);
+    if (!(val & (1 << BIT_JOY2_RIGHT))) input->joy2 |= (1 << 3);
+    if (!(val & (1 << BIT_JOY2_FIRE)))  input->joy2 |= (1 << 4);
+
+    // 3. Mouse Buttons
+    input->buttons = 0;
+    if (!(val & (1 << BIT_MOUSE_BT1)))  input->buttons |= (1 << 0);
+    if (!(val & (1 << BIT_MOUSE_BT2)))  input->buttons |= (1 << 1);
+
+    // 4. Mouse Quadrature Decoding (Simplified)
+    // Amiga Mouse uses 2 pulses per axis (Clock/Data or Phase A/B)
+    // Here we treat H-Pulse and V-Pulse as "clocks" and H-Dir/V-Dir as "direction"
+    uint8_t curr_h_pulse = (val >> BIT_MOUSE_H_P) & 1;
+    uint8_t curr_v_pulse = (val >> BIT_MOUSE_V_P) & 1;
+
+    input->mouse_x = 0;
+    if (curr_h_pulse != last_h_pulse) {
+        uint8_t h_dir = (val >> BIT_MOUSE_H_D) & 1;
+        input->mouse_x = (h_dir == curr_h_pulse) ? 1 : -1;
+        last_h_pulse = curr_h_pulse;
+    }
+
+    input->mouse_y = 0;
+    if (curr_v_pulse != last_v_pulse) {
+        uint8_t v_dir = (val >> BIT_MOUSE_V_D) & 1;
+        input->mouse_y = (v_dir == curr_v_pulse) ? 1 : -1;
+        last_v_pulse = curr_v_pulse;
+    }
+}