D3rr 0 Posted December 22, 2011 Share Posted December 22, 2011 hi friends. do MSP-EXP430G2 have 1-wire port ? if yes what pins ? Quote Link to post Share on other sites
zeke 693 Posted December 22, 2011 Share Posted December 22, 2011 Sorry it doesn't have a dedicated 1-wire port but you can create one. Search the forum for ds18b20 and it will give you lots of results. We've been working on 1-wire stuff a lot this year. Feel free to ask us questions and we'll guide you in the right direction. Quote Link to post Share on other sites
D3rr 0 Posted December 23, 2011 Author Share Posted December 23, 2011 Sorry it doesn't have a dedicated 1-wire port but you can create one. Search the forum for ds18b20 and it will give you lots of results. We've been working on 1-wire stuff a lot this year. Feel free to ask us questions and we'll guide you in the right direction. how is it possible ? well i was searching for it but all is about code and didnt find nothing about "creating 1-wire" please some details. very thanks for replaying! Quote Link to post Share on other sites
bluehash 1,581 Posted December 23, 2011 Share Posted December 23, 2011 search.php?st=0&sk=t&sd=d&sr=posts&keywords=ds18b20 Quote Link to post Share on other sites
D3rr 0 Posted December 23, 2011 Author Share Posted December 23, 2011 before posting it i was reading a lot and i hope now i will get more usefull info... ;/ i didn't find anything about solding goldpins to create 1-wire or dunno what else possibilities are there... neither i found nothing about any extra parts to my launchpad to make 1-wire it's my first time with 1 wire and my launchpad dont support it, and u guys r giving me search results with posts with lots of code when i even dont know how to make my launchpad supporting 1-wire, great! :!!!: there are many examples with dallas 18b20 so lets take it as example from datasheet i found out that it has 3 lines like GND, Vcc and DATA_LINE so if i connect it like that to my launchpad gnd to gnd + vcc to vcc + data_line to any free port like P2.0 and it will be working ok ? so where is idea of 1-wire here ? stiupid imo if it's ok... Quote Link to post Share on other sites
RobG 1,892 Posted December 23, 2011 Share Posted December 23, 2011 First of all, can you tell us what are you trying to achieve? What's your objective? 1-wire is a simple bus system and practically all MCUs can support it. Also, since 1-wire is implemented in software (there's no hardware module for that,) any pin can be used. The only extra parts that you may need are transistor and couple of resistors. It's called one wire because all communication occurs over one wire. You always need GND which is the second wire, but you do not count it. Vcc can come from the master (MCU) in which case you add 3rd wire (which you also do not count,) or from another source on the sensor side, like a battery. GeekDoc 1 Quote Link to post Share on other sites
GeekDoc 226 Posted December 23, 2011 Share Posted December 23, 2011 That's what makes this forum great, RobG: You smart guys with endless patience. Quote Link to post Share on other sites
D3rr 0 Posted December 24, 2011 Author Share Posted December 24, 2011 Today i bought DALLAS DS18B20 to use 1-wire. I need to do any program for classes that uses 1-wire, so by reading forum i chose temperature sensor DALLAS 18B20. As far as I said I am using on my classes launchpad MSP-EXP430G2, so how to make it working ? If I got 3 pins on sensor like GND, VCC, DATA LINE so i can simply put them as gnd (from sensor) to gnd (on launchpad) vcc (from sensor) to vcc (on launchpad) data line (from sensor) to (free port) P2.0 (on launchpad) and run sample application, will it be working correctly ? Quote Link to post Share on other sites
Fe2o3Fish 33 Posted December 25, 2011 Share Posted December 25, 2011 How much of the DS18B20 datasheet have you read? Really? If it was more that five pages you'd know the answer to your question (yes, the answer's on page 6). Anyhoot, you will need a 4k7 pullup resistor 'tween your data line and Vcc otherwise the 18B20 can't talk back to the controller. It's always good to check out the datasheets for whatever parts you're planning to interface with, OK? -Rusty- Quote Link to post Share on other sites
D3rr 0 Posted December 27, 2011 Author Share Posted December 27, 2011 How much of the DS18B20 datasheet have you read? Really? If it was more that five pages you'dknow the answer to your question (yes, the answer's on page 6). Anyhoot, you will need a 4k7 pullup resistor 'tween your data line and Vcc otherwise the 18B20 can't talk back to the controller. It's always good to check out the datasheets for whatever parts you're planning to interface with, OK? -Rusty- I got today 4k7 resistor but there are some problems with using temp sensor, becouse i dont know a few things Is uP any CPU free port like P2.0 ? What is Vpu on that image ? How to connect resistor 4k7 ohm to data line ? I dont know and didnt find it online... do i have to use to do it any special cable or what ? Quote Link to post Share on other sites
RobG 1,892 Posted December 28, 2011 Share Posted December 28, 2011 Maybe this will help a little viewtopic.php?t=450 Quote Link to post Share on other sites
Fe2o3Fish 33 Posted December 28, 2011 Share Posted December 28, 2011 How much of the DS18B20 datasheet have you read? Really? If it was more that five pages you'dknow the answer to your question (yes, the answer's on page 6). Anyhoot, you will need a 4k7 pullup resistor 'tween your data line and Vcc otherwise the 18B20 can't talk back to the controller. It's always good to check out the datasheets for whatever parts you're planning to interface with, OK? -Rusty- I got today 4k7 resistor but there are some problems with using temp sensor, becouse i dont know a few things That's what the datasheets are for -- you to learn and know a few more things. So put that tongue back into your smiley! Is uP any CPU free port like P2.0 ? Yes, any digital output pin. What is Vpu on that image ? Vdd or the processor's supply voltage will work so long as it does not exceed the maximum voltage for the 1-wire device or the uP's output pin. The DS18B20 can work from 3.3-volts from the LP's supply. Best to keep this at no more than the uP's Vcc for fear that it can zap the pin if it's too high. There are cases where open collector pins can handle higher voltages but... unless you know, keep it at no more than the supply voltage. How to connect resistor 4k7 ohm to data line ? I dont know and didnt find it online... do i have to use to do it any special cable or what ? No, it is used to apply positive voltage to the data line -- no special cables are needed. The data line is supposed to be driven to ground (0-volts) or high impedence (open collector). The resistor allows the data line to go to positive voltage when the output goes open collector. The open collector state also permits the 1-wire device to talk back or respond to the uP, say with the temperature reading requested. Using open collector states prevents either device on the data line from accidentally shorting the other device's pin by applying the opposite voltage, say when the uP is grounding the line and the 1-wire device wants to drive the dataline high. -Rusty- Quote Link to post Share on other sites
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