blob: 92b947927917293710f1c73323f97d2f008cc4eb (
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
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
|
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2010 Marcin Bukat
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "cpu.h"
#include "system.h"
#include "kernel.h"
#include "thread.h"
#include "adc.h"
volatile unsigned short adc_data[NUM_ADC_CHANNELS] IBSS_ATTR;
/* Reading takes 4096 adclk ticks
* 1) tick task is created that enables ADC interrupt
* 2) On interrupt single channel is readed and
* ADC is prepared for next channel
* 3) When all 4 channels are scanned ADC interrupt is disabled
*/
void ADC(void) __attribute__ ((interrupt_handler,section(".icode")));
void ADC(void)
{
static unsigned char channel IBSS_ATTR;
/* read current value */
adc_data[(channel&0x03)] = ADVALUE;
/* switch channel
*
* set source remark
* ADCONFIG is 16bit wide so we have to shift data by 16bits left
* thats why we shift <<24 instead of <<8
*/
channel++;
and_l(~(0x03<<24),&ADCONFIG);
or_l( (((channel&0x03) << 8 )|(1<<7))<<16, &ADCONFIG);
if ( (channel & 0x03) == 0 )
/* disable ADC interrupt */
and_l((~(1<<6))<<16,&ADCONFIG);
}
unsigned short adc_scan(int channel)
{
/* maybe we can drop &0x03 part */
return adc_data[(channel&0x03)];
}
void adc_tick(void)
{
/* enable ADC interrupt */
or_l( ((1<<6))<<16, &ADCONFIG);
}
void adc_init(void)
{
/* GPIO38 GPIO39 */
and_l(~((1<<6)|(1<<7)), &GPIO1_FUNCTION);
/* ADOUT_SEL = 01
* SOURCE SELECT = 000
* CLEAR INTERRUPT FLAG
* ENABLE INTERRUPT = 0
* ADOUT_DRIVE = 00
* ADCLK_SEL = 011 (busclk/8)
*/
ADCONFIG = (1<<10)|(1<<8)|(1<<7)|0x03;
/* ADC interrupt level 4.0 */
or_l((4<<28), &INTPRI8);
/* create tick task which enables ADC interrupt */
tick_add_task(adc_tick);
/* let the interrupt handler fill readout array */
sleep(2);
}
|
