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#include <pic16f84a.h>
typedef unsigned char uint8_t;
__sfr __at(0x70) UART_TX;
__sfr __at(0x71) UART_RX;
__sfr __at(0x72) UART_STATUS;
static volatile uint8_t _d0, _d1, _d2;
// Custom delay to make the output readable at 50MHz
static void delay(void) {
_d0 = 0;
do {
_d1 = 0;
do {
_d2 = 0;
do { _d2++; } while (_d2 != 0);
} while (++_d1 != 50); // Increased for 50MHz visibility
_d0++;
} while (_d0 != 20);
}
static void uart_send(uint8_t byte) {
while (UART_STATUS & 0x01);
UART_TX = byte;
}
static void uart_puts_rom(const char *s) {
while (*s) {
uart_send((uint8_t)*s);
s++;
}
}
// Simple BCD printer for 8-bit numbers
void print_uint8(uint8_t v) {
uint8_t started = 0;
// Hundreds
if (v >= 200) { uart_send('2'); v -= 200; started = 1; }
else if (v >= 100) { uart_send('1'); v -= 100; started = 1; }
// Tens
uint8_t tens = '0';
while (v >= 10) { v -= 10; tens++; }
if (started || tens != '0') { uart_send(tens); }
// Units
uart_send(v + '0');
}
void main(void) {
uint8_t a, b, next;
uart_puts_rom("\x1B[2J\x1B[H"); // Clear screen, Home cursor
uart_puts_rom("PIC16F84A @ 50MHz Fibonacci\r\n");
uart_puts_rom("---------------------------\r\n");
while (1) {
a = 0;
b = 1;
while (a <= 233) { // Max 8-bit Fib is 233
print_uint8(a);
uart_puts_rom(", ");
next = a + b;
a = b;
b = next;
delay();
// Break before overflow
if (a == 233) {
print_uint8(a);
break;
}
}
uart_puts_rom("\r\nRestarting...\r\n");
delay();
}
}
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