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