d8a3fd2194
git-svn-id: https://svn.salfter.gotdns.org/svn/a2bfc/trunk@89 1b90f75b-8b96-4784-87c0-14078182fce6
41 lines
821 B
C
41 lines
821 B
C
#include "ow-temp.h"
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#include <errno.h>
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short ow_temp_read(unsigned char* devid, unsigned char format)
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{
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unsigned char data[8];
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short rawtemp;
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unsigned char i;
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if (!ow_temp_idcheck(devid))
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{
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errno=EINVAL;
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return -1;
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}
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ow_selectdevice(devid);
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ow_writebyte(68); // ask for a temperature reading
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ow_wait(); // wait for operation to complete
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ow_selectdevice(devid);
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ow_writebyte(190); // retrieve the reading
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for (i=0; i<8; i++)
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data[i]=ow_readbyte();
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rawtemp=(short)(data[0]+((int)data[1]<<8));
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errno=0;
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switch (format)
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{
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case OW_TEMP_FAHRENHEIT:
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return (rawtemp*9+8)/80+32;
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case OW_TEMP_CELSIUS:
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return (rawtemp+8)>>4;
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case OW_TEMP_RAW:
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default:
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return rawtemp;
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}
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}
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unsigned char ow_temp_idcheck(unsigned char* devid)
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{
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return (devid[0]==40)?1:0;
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}
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