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path: root/firmware/drivers/adc-as3514.c
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Diffstat (limited to 'firmware/drivers/adc-as3514.c')
-rw-r--r--firmware/drivers/adc-as3514.c32
1 files changed, 5 insertions, 27 deletions
diff --git a/firmware/drivers/adc-as3514.c b/firmware/drivers/adc-as3514.c
index 8c661eb133..3b411a379d 100644
--- a/firmware/drivers/adc-as3514.c
+++ b/firmware/drivers/adc-as3514.c
@@ -26,40 +26,18 @@
26/* Read 10-bit channel data */ 26/* Read 10-bit channel data */
27unsigned short adc_read(int channel) 27unsigned short adc_read(int channel)
28{ 28{
29 unsigned short data = 0; 29 unsigned char buf[2];
30
31 if ((unsigned)channel >= NUM_ADC_CHANNELS)
32 return 0;
33 30
34 ascodec_lock(); 31 ascodec_lock();
35 32
36 /* Select channel */ 33 /* Select channel */
37 if (ascodec_write(AS3514_ADC_0, (channel << 4)) >= 0) 34 ascodec_write(AS3514_ADC_0, (channel << 4));
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 35
52 36 ascodec_readbytes(AS3514_ADC_0, 2, buf);
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 37
60 ascodec_unlock(); 38 ascodec_unlock();
61 39
62 return data; 40 return (((buf[0] & 0x3) << 8) | buf[1]);
63} 41}
64 42
65void adc_init(void) 43void adc_init(void)