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Diffstat (limited to 'firmware/drivers/adc-as3514.c')
-rw-r--r--firmware/drivers/adc-as3514.c67
1 files changed, 67 insertions, 0 deletions
diff --git a/firmware/drivers/adc-as3514.c b/firmware/drivers/adc-as3514.c
new file mode 100644
index 0000000000..8c661eb133
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+++ b/firmware/drivers/adc-as3514.c
@@ -0,0 +1,67 @@
1/***************************************************************************
2 * __________ __ ___.
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7 * \/ \/ \/ \/ \/
8 * $Id$
9 *
10 * Copyright (C) 2006 by Barry Wardell
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation; either version 2
15 * of the License, or (at your option) any later version.
16 *
17 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
18 * KIND, either express or implied.
19 *
20 ****************************************************************************/
21#include "adc.h"
22#include "kernel.h"
23#include "ascodec.h"
24#include "as3514.h"
25
26/* Read 10-bit channel data */
27unsigned short adc_read(int channel)
28{
29 unsigned short data = 0;
30
31 if ((unsigned)channel >= NUM_ADC_CHANNELS)
32 return 0;
33
34 ascodec_lock();
35
36 /* Select channel */
37 if (ascodec_write(AS3514_ADC_0, (channel << 4)) >= 0)
38 {
39 unsigned char buf[2];
40
41 /*
42 * The AS3514 ADC will trigger an interrupt when the conversion
43 * is finished, if the corresponding enable bit in IRQ_ENRD2
44 * is set.
45 * Previously the code did not wait and this apparently did
46 * not pose any problems, but this should be more correct.
47 * Without the wait the data read back may be completely or
48 * partially (first one of the two bytes) stale.
49 */
50 ascodec_wait_adc_finished();
51
52
53 /* Read data */
54 if (ascodec_readbytes(AS3514_ADC_0, 2, buf) >= 0)
55 {
56 data = (((buf[0] & 0x3) << 8) | buf[1]);
57 }
58 }
59
60 ascodec_unlock();
61
62 return data;
63}
64
65void adc_init(void)
66{
67}