blob: f8bc8bb4a395bdcb0bb0e8e4f9e315e6667d9cbf (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
|
/*
* Linear Technology LTC1446 D/A Converter
* Device driver
*
* Copyright (C) 2007 Michael Buesch <m@bues.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include "ltc1446.h"
#include "util.h"
#include <avr/io.h>
/* The hardware connection definitions */
#define LTC1446_PORT PORTD
#define LTC1446_DDR DDRD
#define LTC1446_CLK (1 << 4) /* Clock pin */
#define LTC1446_DIN (1 << 5) /* Data input pin */
#define LTC1446_CS (1 << 6) /* Chip select pin */
/* Put a data word into the device. */
static void ltc1446_put(uint16_t data)
{
uint16_t mask;
uint8_t bits = 12; /* 12 bit resolution */
/* The bits are shifted MSB to LSB into the device. */
mask = (1 << (bits - 1));
do {
if (data & mask)
LTC1446_PORT |= LTC1446_DIN;
else
LTC1446_PORT &= ~LTC1446_DIN;
LTC1446_PORT |= LTC1446_CLK;
_delay_us(1);
LTC1446_PORT &= ~LTC1446_CLK;
_delay_us(1);
mask >>= 1;
} while (--bits);
}
void ltc1446_init(void)
{
LTC1446_DDR |= (LTC1446_CLK | LTC1446_DIN | LTC1446_CS);
LTC1446_PORT &= ~(LTC1446_CLK | LTC1446_DIN);
LTC1446_PORT |= LTC1446_CS;
_delay_ms(10);
ltc1446_write(0, 0);
}
void ltc1446_write(uint16_t chan_a, uint16_t chan_b)
{
LTC1446_PORT &= ~LTC1446_CS;
_delay_us(50);
ltc1446_put(chan_a);
ltc1446_put(chan_b);
LTC1446_PORT |= LTC1446_CS;
_delay_us(50);
}
|
