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comparison src/avriotools.c @ 0:a0ce8ebf2f18

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LED on PINB0 & PINB1 and UART testing. - LED flasing on PINB0 & PINB1. - print 'hello' messages to UART for every flashing round.
author Thinker K.F. Li <thinker@branda.to>
date Sat, 21 Feb 2009 15:49:59 +0800
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-1:000000000000 0:a0ce8ebf2f18
1 #include "avriotools.h"
2 #include <avr/io.h>
3
4 typedef struct _port_regs {
5 volatile uint8_t *port, *ddr, *pin;
6 } port_regs_t;
7
8 static port_regs_t regs[] = {
9 { &PORTB, &DDRB, &PINB },
10 { &PORTD, &DDRD, &PIND }
11 };
12 #define NPORTS (sizeof(regs) / sizeof(*regs))
13
14 #define ERR -1
15 #define OK 0
16
17 int pin_mode(volatile uint8_t * port, int pin, pin_mode_t mode) {
18 port_regs_t *preg;
19 int i;
20
21 for(i = 0; i < NPORTS; i++) {
22 preg = regs + i;
23 if(preg->port == port)
24 break;
25 }
26 if(i == NPORTS)
27 return ERR;
28
29 switch(mode) {
30 case PM_INPUT:
31 *preg->ddr &= ~_BV(pin);
32 *preg->port |= _BV(pin);
33 break;
34
35 case PM_OUTPUT:
36 *preg->ddr |= _BV(pin);
37 break;
38
39 default:
40 return ERR;
41 }
42
43 return OK;
44 }
45
46 /* To make setbaud.h no more complaint */
47 #define BAUD 9600
48 #include <util/setbaud.h>
49
50 int uart_init(uint32_t baud) {
51 unsigned long ubrr_v;
52 long err;
53
54 if(baud > (F_CPU / 8))
55 return ERR;
56
57 #define F_CPUx2 (F_CPU * 2UL)
58
59 ubrr_v = (F_CPU + baud * 8UL) / (baud * 16UL) - 1UL;
60 /* Allow bias of baud rate in 2%, or use U2X clock.
61 * ATmega168 divides baud rate generator clock by 2, 8, or 16.
62 * Setting U2X bit makes the clock divided by 8 instead of 16.
63 * It makes more accurately output and higher max baud rate.
64 */
65 err = 16L * 100L * (ubrr_v + 1) * baud - F_CPU * 100L;
66 if(err > F_CPUx2 || err < -F_CPUx2 || ubrr_v < 2) {
67 ubrr_v = (F_CPU + baud * 4UL) / (baud * 8UL) - 1UL;
68 UCSRA |= (1 << U2X);
69 } else {
70 UCSRA &= ~(1 << U2X);
71 }
72
73 UBRRH = ubrr_v >> 8;
74 UBRRL = ubrr_v & 0xff;
75 return OK;
76 }