Per connettere un keypad 4x4 ad una Arduino sono necessari 8 cavi di collegamento. In questo caso il pin piu' a sinistra del connettore della tasteria (colore blu) si collega al pin D9 di Arduino e cosi' via scendendo via al pin D2
Partendo dal precedente post ho portato il codice su Arduino
Per il progetto ho usato una Arduino Mega con un schermo Oled 0.91" di 128x32 pixels (il CHIP-8 aveva uno schermo 64x32 monocromatico basato su U8G2) ed un keypad a 16 pulsanti (CHIP-8 gestiva una tastiera a 16 tasti)
il primo passo e' stato quello di usare la classe chip8 per creare una libreria Arduino.
Si crea un sottodirectory chip8 in /libraries e si creano i file chip8.cpp e chip8.h
Rispetto alla versione NCurses sono stati rimossi dei comandi che hanno riscontro in Arduino (per esempio iostream o sizeof ) Credits James Griffin
chip8.cpp
----------------------------------------------------------------- #include <stdio.h> #include <stdlib.h> //#include <iostream> //#include <random> #include "time.h" #include "chip8.h" unsigned char chip8_fontset[80] = { 0xF0, 0x90, 0x90, 0x90, 0xF0, //0 0x20, 0x60, 0x20, 0x20, 0x70, //1 0xF0, 0x10, 0xF0, 0x80, 0xF0, //2 0xF0, 0x10, 0xF0, 0x10, 0xF0, //3 0x90, 0x90, 0xF0, 0x10, 0x10, //4 0xF0, 0x80, 0xF0, 0x10, 0xF0, //5 0xF0, 0x80, 0xF0, 0x90, 0xF0, //6 0xF0, 0x10, 0x20, 0x40, 0x40, //7 0xF0, 0x90, 0xF0, 0x90, 0xF0, //8 0xF0, 0x90, 0xF0, 0x10, 0xF0, //9 0xF0, 0x90, 0xF0, 0x90, 0x90, //A 0xE0, 0x90, 0xE0, 0x90, 0xE0, //B 0xF0, 0x80, 0x80, 0x80, 0xF0, //C 0xE0, 0x90, 0x90, 0x90, 0xE0, //D 0xF0, 0x80, 0xF0, 0x80, 0xF0, //E 0xF0, 0x80, 0xF0, 0x80, 0x80 //F }; Chip8::Chip8() {} Chip8::~Chip8() {} // Initialise void Chip8::init() { pc = 0x200; // Set program counter to 0x200 opcode = 0; // Reset op code I = 0; // Reset I sp = 0; // Reset stack pointer // Clear the display for (int i = 0; i < 2048; ++i) { gfx[i] = 0; } // Clear the stack, keypad, and V registers for (int i = 0; i < 16; ++i) { stack[i] = 0; key[i] = 0; V[i] = 0; } // Clear memory for (int i = 0; i < 4096; ++i) { memory[i] = 0; } // Load font set into memory for (int i = 0; i < 80; ++i) { memory[i] = chip8_fontset[i]; } // Reset timers delay_timer = 0; sound_timer = 0; // Seed rng srand (time(NULL)); } // Initialise and load ROM into memory bool Chip8::load(unsigned char programma[],int size) { // Initialise init(); //long rom_size = sizeof(programma); int rom_size = size; // Copy buffer to memory if ((4096-512) > rom_size){ for (int i = 0; i < rom_size; ++i) { memory[i + 512] = (uint8_t)programma[i]; // Load into memory starting // at 0x200 (=512) } } else { //std::cerr << "ROM too large to fit in memory" << std::endl; return false; } return true; } // Emulate one cycle void Chip8::emulate_cycle() { // Fetch op code opcode = memory[pc] << 8 | memory[pc + 1]; // Op code is two bytes switch(opcode & 0xF000){ // 00E_ case 0x0000: switch (opcode & 0x000F) { // 00E0 - Clear screen case 0x0000: for (int i = 0; i < 2048; ++i) { gfx[i] = 0; } drawFlag = true; pc+=2; break; // 00EE - Return from subroutine case 0x000E: --sp; pc = stack[sp]; pc += 2; break; default: //printf("\nUnknown op code: %.4X\n", opcode); exit(3); } break; // 1NNN - Jumps to address NNN case 0x1000: pc = opcode & 0x0FFF; break; // 2NNN - Calls subroutine at NNN case 0x2000: stack[sp] = pc; ++sp; pc = opcode & 0x0FFF; break; // 3XNN - Skips the next instruction if VX equals NN. case 0x3000: if (V[(opcode & 0x0F00) >> 8] == (opcode & 0x00FF)) pc += 4; else pc += 2; break; // 4XNN - Skips the next instruction if VX does not equal NN. case 0x4000: if (V[(opcode & 0x0F00) >> 8] != (opcode & 0x00FF)) pc += 4; else pc += 2; break; // 5XY0 - Skips the next instruction if VX equals VY. case 0x5000: if (V[(opcode & 0x0F00) >> 8] == V[(opcode & 0x00F0) >> 4]) pc += 4; else pc += 2; break; // 6XNN - Sets VX to NN. case 0x6000: V[(opcode & 0x0F00) >> 8] = opcode & 0x00FF; pc += 2; break; // 7XNN - Adds NN to VX. case 0x7000: V[(opcode & 0x0F00) >> 8] += opcode & 0x00FF; pc += 2; break; // 8XY_ case 0x8000: switch (opcode & 0x000F) { // 8XY0 - Sets VX to the value of VY. case 0x0000: V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4]; pc += 2; break; // 8XY1 - Sets VX to (VX OR VY). case 0x0001: V[(opcode & 0x0F00) >> 8] |= V[(opcode & 0x00F0) >> 4]; pc += 2; break; // 8XY2 - Sets VX to (VX AND VY). case 0x0002: V[(opcode & 0x0F00) >> 8] &= V[(opcode & 0x00F0) >> 4]; pc += 2; break; // 8XY3 - Sets VX to (VX XOR VY). case 0x0003: V[(opcode & 0x0F00) >> 8] ^= V[(opcode & 0x00F0) >> 4]; pc += 2; break; // 8XY4 - Adds VY to VX. VF is set to 1 when there's a carry, // and to 0 when there isn't. case 0x0004: V[(opcode & 0x0F00) >> 8] += V[(opcode & 0x00F0) >> 4]; if(V[(opcode & 0x00F0) >> 4] > (0xFF - V[(opcode & 0x0F00) >> 8])) V[0xF] = 1; //carry else V[0xF] = 0; pc += 2; break; // 8XY5 - VY is subtracted from VX. VF is set to 0 when // there's a borrow, and 1 when there isn't. case 0x0005: if(V[(opcode & 0x00F0) >> 4] > V[(opcode & 0x0F00) >> 8]) V[0xF] = 0; // there is a borrow else V[0xF] = 1; V[(opcode & 0x0F00) >> 8] -= V[(opcode & 0x00F0) >> 4]; pc += 2; break; // 0x8XY6 - Shifts VX right by one. VF is set to the value of // the least significant bit of VX before the shift. case 0x0006: V[0xF] = V[(opcode & 0x0F00) >> 8] & 0x1; V[(opcode & 0x0F00) >> 8] >>= 1; pc += 2; break; // 0x8XY7: Sets VX to VY minus VX. VF is set to 0 when there's // a borrow, and 1 when there isn't. case 0x0007: if(V[(opcode & 0x0F00) >> 8] > V[(opcode & 0x00F0) >> 4])// VY-VX V[0xF] = 0; // there is a borrow else V[0xF] = 1; V[(opcode & 0x0F00) >> 8] = V[(opcode & 0x00F0) >> 4] - V[(opcode & 0x0F00) >> 8]; pc += 2; break; // 0x8XYE: Shifts VX left by one. VF is set to the value of // the most significant bit of VX before the shift. case 0x000E: V[0xF] = V[(opcode & 0x0F00) >> 8] >> 7; V[(opcode & 0x0F00) >> 8] <<= 1; pc += 2; break; default: //printf("\nUnknown op code: %.4X\n", opcode); exit(3); } break; // 9XY0 - Skips the next instruction if VX doesn't equal VY. case 0x9000: if (V[(opcode & 0x0F00) >> 8] != V[(opcode & 0x00F0) >> 4]) pc += 4; else pc += 2; break; // ANNN - Sets I to the address NNN. case 0xA000: I = opcode & 0x0FFF; pc += 2; break; // BNNN - Jumps to the address NNN plus V0. case 0xB000: pc = (opcode & 0x0FFF) + V[0]; break; // CXNN - Sets VX to a random number, masked by NN. case 0xC000: V[(opcode & 0x0F00) >> 8] = (rand() % (0xFF + 1)) & (opcode & 0x00FF); pc += 2; break; // DXYN: Draws a sprite at coordinate (VX, VY) that has a width of 8 // pixels and a height of N pixels. // Each row of 8 pixels is read as bit-coded starting from memory // location I; // I value doesn't change after the execution of this instruction. // VF is set to 1 if any screen pixels are flipped from set to unset // when the sprite is drawn, and to 0 if that doesn't happen. case 0xD000: { unsigned short x = V[(opcode & 0x0F00) >> 8]; unsigned short y = V[(opcode & 0x00F0) >> 4]; unsigned short height = opcode & 0x000F; unsigned short pixel; V[0xF] = 0; for (int yline = 0; yline < height; yline++) { pixel = memory[I + yline]; for(int xline = 0; xline < 8; xline++) { if((pixel & (0x80 >> xline)) != 0) { if(gfx[(x + xline + ((y + yline) * 64))] == 1) { V[0xF] = 1; } gfx[x + xline + ((y + yline) * 64)] ^= 1; } } } drawFlag = true; pc += 2; } break; // EX__ case 0xE000: switch (opcode & 0x00FF) { // EX9E - Skips the next instruction if the key stored // in VX is pressed. case 0x009E: if (key[V[(opcode & 0x0F00) >> 8]] != 0) pc += 4; else pc += 2; break; // EXA1 - Skips the next instruction if the key stored // in VX isn't pressed. case 0x00A1: if (key[V[(opcode & 0x0F00) >> 8]] == 0) pc += 4; else pc += 2; break; default: //printf("\nUnknown op code: %.4X\n", opcode); exit(3); } break; // FX__ case 0xF000: switch(opcode & 0x00FF) { // FX07 - Sets VX to the value of the delay timer case 0x0007: V[(opcode & 0x0F00) >> 8] = delay_timer; pc += 2; break; // FX0A - A key press is awaited, and then stored in VX case 0x000A: { bool key_pressed = false; for(int i = 0; i < 16; ++i) { if(key[i] != 0) { V[(opcode & 0x0F00) >> 8] = i; key_pressed = true; } } // If no key is pressed, return and try again. if(!key_pressed) return; pc += 2; } break; // FX15 - Sets the delay timer to VX case 0x0015: delay_timer = V[(opcode & 0x0F00) >> 8]; pc += 2; break; // FX18 - Sets the sound timer to VX case 0x0018: sound_timer = V[(opcode & 0x0F00) >> 8]; pc += 2; break; // FX1E - Adds VX to I case 0x001E: // VF is set to 1 when range overflow (I+VX>0xFFF), and 0 // when there isn't. if(I + V[(opcode & 0x0F00) >> 8] > 0xFFF) V[0xF] = 1; else V[0xF] = 0; I += V[(opcode & 0x0F00) >> 8]; pc += 2; break; // FX29 - Sets I to the location of the sprite for the // character in VX. Characters 0-F (in hexadecimal) are // represented by a 4x5 font case 0x0029: I = V[(opcode & 0x0F00) >> 8] * 0x5; pc += 2; break; // FX33 - Stores the Binary-coded decimal representation of VX // at the addresses I, I plus 1, and I plus 2 case 0x0033: memory[I] = V[(opcode & 0x0F00) >> 8] / 100; memory[I + 1] = (V[(opcode & 0x0F00) >> 8] / 10) % 10; memory[I + 2] = V[(opcode & 0x0F00) >> 8] % 10; pc += 2; break; // FX55 - Stores V0 to VX in memory starting at address I case 0x0055: for (int i = 0; i <= ((opcode & 0x0F00) >> 8); ++i) memory[I + i] = V[i]; // On the original interpreter, when the // operation is done, I = I + X + 1. I += ((opcode & 0x0F00) >> 8) + 1; pc += 2; break; case 0x0065: for (int i = 0; i <= ((opcode & 0x0F00) >> 8); ++i) V[i] = memory[I + i]; // On the original interpreter, // when the operation is done, I = I + X + 1. I += ((opcode & 0x0F00) >> 8) + 1; pc += 2; break; default: break; //printf ("Unknown opcode [0xF000]: 0x%X\n", opcode); } break; default: //printf("\nUnimplemented op code: %.4X\n", opcode); exit(3); } // Update timers if (delay_timer > 0) --delay_timer; if (sound_timer > 0) if(sound_timer == 1); // TODO: Implement sound --sound_timer; }
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