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Jos�
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| DS18B20 request |
 Posted: Mon Jun 27, 2005 4:08 am |
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Hi,
How can i use the DS18B20 (12bit) ???????
can i use the reset, read_byte, write_byte, read_bit, write_bit , from the DS1820??????
How implement a DS18B20 temp. mes.?????
Tkn�s in advance. |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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Jos�
Guest
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| Posted: Mon Jun 27, 2005 7:01 am |
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| Quote: | | First you read the datasheet. Then you write a driver. Maxim already gives source code for that |
Hi,
I already read this, and the sample code is in asm, but i like to use the ccs(but i�m begginer), and the reason for this post is , I need help for CCS code.
And as I said, all the information is for the DS1820, and not for the 18B20.
Note: 0% -> 100%, i�m in 5%. |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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| Posted: Mon Jun 27, 2005 7:23 am |
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Well my brain must be dead then cause this sure looks like C to me
| Code: |
//individual Serial #s and readings
#define DEVICES 4
int ROMS[DEVICES][8];
int TEMPS[DEVICES];
int GetTemperatures(int BASE)
{
// init. the 1-Wire Master
Initialize(BASE);
// exit if no devices can be found
if(Reset(BASE)) return(1);
// find all individual Serial#s
FindROMs(BASE);
// Convert temp. and read devices
ConvertT(BASE);
ReadTemps(BASE);
return(0);
}
void Initialize(int BASE)
{
// Divide the clock
outp(BASE+4,0x0F);
// Generate INTs on reset and send
outp(BASE+3,0x09);
}
int Reset(int BASE)
{
outp(BASE,0x02); // send reset
WaitforInterrupt();
if(inp(BASE+2) & 0x02)
return(1); //no presence found
else
return(0); //presence found
}
int FindROMs(int BASE)
{
int loop;
int dev;
int TData[16];
int RData[16];
// reset RecoverROM and generate the
// starting TData
RecoverROM(NULL,TData,NULL);
//run once for each device
for(dev=0;dev<4;dev++)
{
outp(BASE,0x01); // send reset
WaitforInterrupt();
outp(BASE+1,0xF0); // send SeachROM
WaitforInterrupt();
// enter Accelerator mode
outp(BASE,0x02);
// transmit the TDATA and receive
// the RDATA.
for(loop=0;loop<16;loop++)
{
outp(BASE+1,TData[loop]);
WaitforInterrupt();
inp(BASE+1,RData[loop]);
}
//decode recovered ROM and generate
//next Search value
RecoverROM(RDATA,TData,ROMS[dev]);
}
}
int ConvertT(int BASE)
{
outp(BASE,0x01); // send reset
WaitforInterrupt();
outp(BASE+1,0xCC); // skip ROM
WaitforInterrupt();
outp(BASE+1,0x44); // convert Temp.
WaitforInterrupt();
int ReadTemps(int BASE)
{
int dev,loop;
int LSB,MSB;
for(dev=0;dev<4;dev++)
{
outp(BASE,0x01); // send reset
WaitforInterrupt();
outp(BASE+1,0x55); // match ROM
WaitforInterrupt();
// send 8 bytes of ROM code
for(loop=0;loop<8;loop++)
{
outp(BASE+1,ROMS[dev][loop]);
WaitforInterrupt();
}
outp(BASE+1,0xBE); // read memory
WaitforInterrupt();
outp(BASE+1,0xFF); // read LSB
WaitforInterrupt();
LSB = inp(BASE+1);
outp(BASE+1,0xFF); // read MSB
WaitforInterrupt();
MSB = inp(BASE+1);
TEMPS[dev] = MSB<<8 + LSB;
}
}
/////////////////////////////////////////////////////////////////////////////////
// RecoverROM performs two functions. Given 16 bytes of receive data taken from
// the 1-Wire Master during a Search ROM function, it will extract the ROM code
// found into an 8 byte array and it will generate the next 16 bytes to be trans-
// mitted during the next Search ROM.
// RecoverROM must be initialized by sending a NULL pointer in ReceivedData. It
// will write 16 bytes of zeros into TransmitData and clear the discrepancy tree.
// The discrepancy tree keeps track of which ROM discrepancies have already been
// explored.
// RecoverROM also returns a value telling whether there are any more ROM codes to
// be found. If a zero is returned, there are still discrepancies. If a one is
// returned all ROMs on the bus have been found. Running RecoverROM again in this
// case will result in repeating ROM codes already found
////////////////////////////////////////////////////////////////////////////////
int RecoverROM(int* ReceiveData, int* TransmitData, int* ROMCode)
{
int loop;
int result;
int TROM[64]; // the transmit value being generated
int RROM[64]; // the ROM recovered from the received data
int RDIS[64]; // the discrepancy bits in the received data
static int TREE[64]; // used to keep track of which discrepancy bits have
// already been flipped.
// If receivedata is NULL, this is the first run. Transmit data should be all
// zeros, and the discrepancy tree must also be reset.
if(ReceiveData == NULL)
{
for(loop = 0; loop < 64; loop++) TREE[loop] = 0;
for(loop = 0; loop < 16; loop++) TransmitData[loop] = 0;
return 1;
}
// de-interleave the received data into the new ROM code and the discrepancy bits
for(loop = 0; loop < 16; loop++)
{
if((ReceiveData[loop] & 0x02) == 0x00) RROM[loop*4] = 0; else RROM[loop*4 ] = 1;
if((ReceiveData[loop] & 0x08) == 0x00) RROM[loop*4+1] = 0; else RROM[loop*4+1] = 1;
if((ReceiveData[loop] & 0x20) == 0x00) RROM[loop*4+2] = 0; else RROM[loop*4+2] = 1;
if((ReceiveData[loop] & 0x80) == 0x00) RROM[loop*4+3] = 0; else RROM[loop*4+3] = 1;
if((ReceiveData[loop] & 0x01) == 0x00) RDIS[loop*4] = 0; else RDIS[loop*4 ] = 1;
if((ReceiveData[loop] & 0x04) == 0x00) RDIS[loop*4+1] = 0; else RDIS[loop*4+1] = 1;
if((ReceiveData[loop] & 0x10) == 0x00) RDIS[loop*4+2] = 0; else RDIS[loop*4+2] = 1;
if((ReceiveData[loop] & 0x40) == 0x00) RDIS[loop*4+3] = 0; else RDIS[loop*4+3] = 1;
}
// initialize the transmit ROM to the recovered ROM
for(loop = 0; loop < 64; loop++) TROM[loop] = RROM[loop];
// work through the new transmit ROM backwards setting every bit to 0 until the
// most significant discrepancy bit which has not yet been flipped is found.
// The transmit ROM bit at that location must be flipped.
for(loop = 63; loop >= 0; loop--)
{
// This is a new discrepancy bit. Set the indicator in the tree, flip the
// transmit bit, and then break from the loop.
if((TREE[loop] == 0) && (RDIS[loop] == 1) && (TROM[loop] == 0))
{
TREE[loop] = 1;
TROM[loop] = 1;
break;
}
if((TREE[loop] == 0) && (RDIS[loop] == 1) && (TROM[loop] == 1))
{
TREE[loop] = 1;
TROM[loop] = 0;
break;
}
// This bit has already been flipped, remove it from the tree and continue
// setting the transmit bits to zero.
if((TREE[loop] == 1) && (RDIS[loop] == 1)) TREE[loop] = 0;
TROM[loop] = 0;
}
result = loop; // if loop made it to -1, there are no more discrepancy bits
// and the search can end.
// Convert the individual transmit ROM bit into a 16 byte format
// every other bit is don't care.
for(loop = 0; loop < 16; loop++)
{
TransmitData[loop] = (TROM[loop*4]<<1) +
(TROM[loop*4+1]<<3) +
(TROM[loop*4+2]<<5) +
(TROM[loop*4+3]<<7);
}
// Convert the individual recovered ROM bits into an 8 byte format
for(loop = 0; loop < 8; loop++)
{
ROMCode[loop] = (RROM[loop*8]) +
(RROM[loop*8+1]<<1) +
(RROM[loop*8+2]<<2) +
(RROM[loop*8+3]<<3) +
(RROM[loop*8+4]<<4) +
(RROM[loop*8+5]<<5) +
(RROM[loop*8+6]<<6) +
(RROM[loop*8+7]<<7);
}
if(result == -1) return 1; // There are no DIS bits that haven't been flipped
// Tell the main loop the seach is over
return 0; // else continue
}
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Its not in CCS C but shouldn't be a problem to convert it. |
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Mark
Joined: 07 Sep 2003
Posts: 2838
Location: Atlanta, GA
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jds-pic
Joined: 17 Sep 2003
Posts: 205
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Guest
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| Posted: Mon Jun 27, 2005 8:37 am |
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Who does not know is as a blind person, and I am starting to see, and open my eyes.
So thanks for all info�s.
(in the search I had an error in the words, thought that it got a better result if it is looked for 1820 or 18b20, but not. But as it said I am to start to open the eyes.)
I wait in a next time not to commit as many basic errors.
Debtor to all the involved ones. |
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