TMP75C: Tmp75c temp sensor

Bill hicks

Part Number: TMP75C

i am developing a project that has a MP430FR2311 and aTMP75C temp sensor. I have been unable to get an acknowledgement from the temp sensor. I have used I2c routines that i have used with other MP430 processes as well as the example code provided with the MP430FR2311. I am still not able to get the temp sensor to respond. I connect another i2c chip BQ3200 and was able to get an acknowlegement as well as being able to read and write. Is there something that i am missing when trying to address the TMP75c.

thanks

Bill

over 6 years ago

0 Ren Schackmann over 6 years ago

TI__Mastermind 35835 points

Hi Bill,

Which I2C Address are you using? Did you connect the TMP75C's address pins?

Thanks,
Ren

0 Bill hicks over 6 years ago in reply to Ren Schackmann

Prodigy 140 points

Hi Ren

all the address pins were grounded. The address i used was 0x48. i had a BQ3200 on the bus with an address of 0x68. i have a file that contains the output sending one byte plus address. As you will see the tmp75c does not acknowledge where the BP3200 does. I also wrote a bit bang routine and got similar results. i have also included the code used . The micro i am using is the MP430FR2311. I have tried to determine if i am missing something as the tmp75c is an SMB bus.

Snap Shots of the different results using tmp75c and the BQ3200 that are on the same board/bus

Snap Shots of the different results using tmp75c and the BQ3200 that are on the same board.docx

0 Ren Schackmann over 6 years ago in reply to Bill hicks

TI__Mastermind 35835 points

Hi Bill,

I'm going to need more information to find the problem. Can you share the schematic? Also, the source code appears incomplete. Can you share the complete source code?

Thanks,
Ren

0 Bill hicks over 6 years ago in reply to Ren Schackmann

Prodigy 140 points

i2c.pdf init.pdf patch_main.pdf 2548.patch_main.pdf 0081.Schematic Prints.pdfhi Ben

attached find the documents you requested. Thank for helping. This has me stump especially when i can read and write to

bq3200

0 Bill hicks over 6 years ago in reply to Bill hicks

Prodigy 140 points

the code i sent you had the address for BQ3200 of 0x68. i did use 0x48 for the address for tmp75c

0 Bill hicks over 6 years ago in reply to Bill hicks

Prodigy 140 points

Hi Ren
Could the TMP75c be timing out? I compared the signal to specifications and seems timing is ok.

0 Ren Schackmann over 6 years ago in reply to Bill hicks

TI__Mastermind 35835 points

I see that BQ3200 is not included in this design, so I assume that you have previous experience with it.

The schematic looks fine with the exception of P1.1. Why did you short this pin to P1.3/SCL? Regardless, this doesn't seem to be related to your issue.

Are you sure this is the same code that was verified with BQ3200? I don't see a byte being transferred after the Address byte. I would expect to see a reference to UCB0TXBUF register instead of your variable PTx_I2CData.

If you need additional support with your programming, you would be better served by asking in the MSP430 Forums. We don't have as much expertise here in the Temperature Sensor forum. e2e.ti.com/.../

Thanks,
Ren

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TMP75C: Tmp75c temp sensor