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| 1 | 6 | kaklik | /*! \file ads7828.c \brief TI ADS7828 12-bit 8ch A/D Converter Driver Library. */ |
| 2 | //***************************************************************************** |
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| 3 | // |
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| 4 | // File Name : 'ads7828.c' |
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| 5 | // Title : TI ADS7828 12-bit 8ch A/D Converter Driver Library |
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| 6 | // Author : Pascal Stang - Copyright (C) 2004 |
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| 7 | // Created : 2004.02.10 |
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| 8 | // Revised : 2004.02.19 |
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| 9 | // Version : 0.1 |
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| 10 | // Target MCU : Atmel AVR Series |
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| 11 | // Editor Tabs : 4 |
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| 12 | // |
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| 13 | // NOTE: This code is currently below version 1.0, and therefore is considered |
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| 14 | // to be lacking in some functionality or documentation, or may not be fully |
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| 15 | // tested. Nonetheless, you can expect most functions to work. |
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| 16 | // |
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| 17 | // This code is distributed under the GNU Public License |
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| 18 | // which can be found at http://www.gnu.org/licenses/gpl.txt |
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| 19 | // |
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| 20 | //***************************************************************************** |
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| 21 | |||
| 22 | #include <avr/io.h> |
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| 23 | #include <avr/interrupt.h> |
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| 24 | |||
| 25 | #include "global.h" |
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| 26 | #include "i2c.h" |
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| 27 | #include "ads7828.h" |
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| 28 | |||
| 29 | // global variables |
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| 30 | u08 Ads7282RefMode; |
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| 31 | |||
| 32 | // Functions |
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| 33 | u08 ads7828Init(u08 i2cAddr) |
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| 34 | { |
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| 35 | u08 channel = 0x80; |
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| 36 | |||
| 37 | // setup default A/D voltage reference |
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| 38 | ads7828SetReference(0); |
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| 39 | |||
| 40 | // issue a convserion to test chip presence |
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| 41 | // return TRUE if chip detected |
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| 42 | // return FALSE if chip does not respond |
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| 43 | return (i2cMasterSendNI(i2cAddr, 1, &channel) == I2C_OK); |
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| 44 | } |
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| 45 | |||
| 46 | u16 ads7828Convert(u08 i2cAddr, u08 channel) |
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| 47 | { |
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| 48 | // re-order channel bits for |
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| 49 | // logical single-ended channel selection |
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| 50 | // channel bit0 -> C2 |
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| 51 | // channel bit1 -> C0 |
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| 52 | // channel bit2 -> C1 |
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| 53 | channel = (((channel>>1) | (channel&0x01)<<2)<<4) | ADS7828_CMD_SD; |
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| 54 | // do conversion |
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| 55 | return ads7828ConvertRaw(i2cAddr, channel); |
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| 56 | } |
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| 57 | |||
| 58 | u16 ads7828ConvertDiff(u08 i2cAddr, u08 channel) |
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| 59 | { |
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| 60 | // clear single-ended channel bit |
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| 61 | channel = (channel&0x07)<<4; |
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| 62 | // do conversion |
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| 63 | return ads7828ConvertRaw(i2cAddr, channel); |
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| 64 | } |
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| 65 | |||
| 66 | u16 ads7828ConvertRaw(u08 i2cAddr, u08 channel) |
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| 67 | { |
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| 68 | u08 buffer[2]; |
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| 69 | // combine raw channel and reference bits |
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| 70 | channel &= 0xF0; |
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| 71 | channel |= Ads7282RefMode; |
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| 72 | // start conversion on requested channel |
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| 73 | i2cMasterSendNI(i2cAddr, 1, &channel); |
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| 74 | // retrieve conversion result |
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| 75 | i2cMasterReceiveNI(i2cAddr, 2, buffer); |
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| 76 | // pack bytes and return result |
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| 77 | return ((buffer[0]<<8) | buffer[1]); |
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| 78 | } |
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| 79 | |||
| 80 | void ads7828SetReference(u08 ref) |
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| 81 | { |
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| 82 | if(ref) |
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| 83 | { |
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| 84 | // use internal reference |
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| 85 | Ads7282RefMode = ADS7828_CMD_PDMODE2; |
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| 86 | } |
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| 87 | else |
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| 88 | { |
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| 89 | // use external reference |
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| 90 | Ads7282RefMode = ADS7828_CMD_PDMODE0; |
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| 91 | } |
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| 92 | } |
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