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author | Jens Arnold <amiconn@rockbox.org> | 2007-04-15 23:35:56 +0000 |
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committer | Jens Arnold <amiconn@rockbox.org> | 2007-04-15 23:35:56 +0000 |
commit | 7a5d4011f56334c05b55bb511c2f1f6a4639c8c1 (patch) | |
tree | 402f35138b44ac7bb3b7005fbf58c785cc02c9e5 /firmware/target/sh/adc-sh.c | |
parent | 36ba4b02bd69dc5fec4cdb6bc4684d77a888bbbe (diff) | |
download | rockbox-7a5d4011f56334c05b55bb511c2f1f6a4639c8c1.tar.gz rockbox-7a5d4011f56334c05b55bb511c2f1f6a4639c8c1.zip |
Moved SH1 ADC to target tree.
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@13174 a1c6a512-1295-4272-9138-f99709370657
Diffstat (limited to 'firmware/target/sh/adc-sh.c')
-rw-r--r-- | firmware/target/sh/adc-sh.c | 108 |
1 files changed, 108 insertions, 0 deletions
diff --git a/firmware/target/sh/adc-sh.c b/firmware/target/sh/adc-sh.c new file mode 100644 index 0000000000..d36624f913 --- /dev/null +++ b/firmware/target/sh/adc-sh.c | |||
@@ -0,0 +1,108 @@ | |||
1 | /*************************************************************************** | ||
2 | * __________ __ ___. | ||
3 | * Open \______ \ ____ ____ | | _\_ |__ _______ ___ | ||
4 | * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ / | ||
5 | * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < < | ||
6 | * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \ | ||
7 | * \/ \/ \/ \/ \/ | ||
8 | * $Id$ | ||
9 | * | ||
10 | * Copyright (C) 2002 by Linus Nielsen Feltzing | ||
11 | * | ||
12 | * All files in this archive are subject to the GNU General Public License. | ||
13 | * See the file COPYING in the source tree root for full license agreement. | ||
14 | * | ||
15 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY | ||
16 | * KIND, either express or implied. | ||
17 | * | ||
18 | ****************************************************************************/ | ||
19 | #include "config.h" | ||
20 | #include "cpu.h" | ||
21 | #include "system.h" | ||
22 | #include "kernel.h" | ||
23 | #include "thread.h" | ||
24 | #include "string.h" | ||
25 | #include "adc.h" | ||
26 | |||
27 | /************************************************************************** | ||
28 | ** The A/D conversion is done every tick, in three steps: | ||
29 | ** | ||
30 | ** 1) On the tick interrupt, the conversion of channels 0-3 is started, and | ||
31 | ** the A/D interrupt is enabled. | ||
32 | ** | ||
33 | ** 2) After the conversion is done (approx. 256*4 cycles later), an interrupt | ||
34 | ** is generated at level 1, which is the same level as the tick interrupt | ||
35 | ** itself. This interrupt will be pending until the tick interrupt is | ||
36 | ** finished. | ||
37 | ** When the A/D interrupt is finally served, it will read the results | ||
38 | ** from the first conversion and start the conversion of channels 4-7. | ||
39 | ** | ||
40 | ** 3) When the conversion of channels 4-7 is finished, the interrupt is | ||
41 | ** triggered again, and the results are read. This time, no new | ||
42 | ** conversion is started, it will be done in the next tick interrupt. | ||
43 | ** | ||
44 | ** Thus, each channel will be updated HZ times per second. | ||
45 | ** | ||
46 | *************************************************************************/ | ||
47 | |||
48 | static int current_channel; | ||
49 | static unsigned short adcdata[NUM_ADC_CHANNELS]; | ||
50 | |||
51 | static void adc_tick(void) | ||
52 | { | ||
53 | /* Start a conversion of channel group 0. This will trigger an interrupt, | ||
54 | and the interrupt handler will take care of group 1. */ | ||
55 | |||
56 | current_channel = 0; | ||
57 | ADCSR = ADCSR_ADST | ADCSR_ADIE | ADCSR_SCAN | 3; | ||
58 | } | ||
59 | |||
60 | void ADITI(void) __attribute__((interrupt_handler)); | ||
61 | void ADITI(void) | ||
62 | { | ||
63 | if(ADCSR & ADCSR_ADF) | ||
64 | { | ||
65 | ADCSR = 0; | ||
66 | |||
67 | if(current_channel == 0) | ||
68 | { | ||
69 | adcdata[0] = ADDRA >> 6; | ||
70 | adcdata[1] = ADDRB >> 6; | ||
71 | adcdata[2] = ADDRC >> 6; | ||
72 | adcdata[3] = ADDRD >> 6; | ||
73 | current_channel = 4; | ||
74 | |||
75 | /* Convert the next group */ | ||
76 | ADCSR = ADCSR_ADST | ADCSR_ADIE | ADCSR_SCAN | 7; | ||
77 | } | ||
78 | else | ||
79 | { | ||
80 | adcdata[4] = ADDRA >> 6; | ||
81 | adcdata[5] = ADDRB >> 6; | ||
82 | adcdata[6] = ADDRC >> 6; | ||
83 | adcdata[7] = ADDRD >> 6; | ||
84 | } | ||
85 | } | ||
86 | } | ||
87 | |||
88 | unsigned short adc_read(int channel) | ||
89 | { | ||
90 | return adcdata[channel]; | ||
91 | } | ||
92 | |||
93 | void adc_init(void) | ||
94 | { | ||
95 | ADCR = 0x7f; /* No external trigger; other bits should be 1 according | ||
96 | to the manual... */ | ||
97 | |||
98 | ADCSR = 0; | ||
99 | |||
100 | current_channel = 0; | ||
101 | |||
102 | /* Enable the A/D IRQ on level 1 */ | ||
103 | IPRE = (IPRE & 0xf0ff) | 0x0100; | ||
104 | |||
105 | tick_add_task(adc_tick); | ||
106 | |||
107 | sleep(2); /* Ensure valid readings when adc_init returns */ | ||
108 | } | ||