Ivan Jajcevic

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10 years, 12 months ago.

TCN75A I2C temperature sensor

I have digilent board (boosterpack) http://www.digilentinc.com/Products/Detail.cfm?NavPath=2,396,1181&Prod=ORBIT-BOOSTER which has on board temperature sensor TCN75A http://www.microchip.com/wwwproducts/Devices.aspx?product=TCN75A. I can not have response from this temperature sensor over I2C bus on mbed. Please help. /media/uploads/Eggy/tcn75a.jpg

1 Answer

Ivan Jajcevic
poster
10 years, 12 months ago.

i figure it out... i2c address of TCN75A is wrong in Digilent datasheet for Orbit BoosterPack it must be 0x9E instead of 0x4F. I figure it out with I2CU http://developer.mbed.org/users/simon/code/I2CU/file/4f78cdfc99de/main.cpp

This is a common "mistake". An I2C address is 7 bits plus a R/W bit in the LSB. So depending on whether the address is specified as a 7 bit or an 8 bit address it will be written as 0x4F or 0x9E which is 0x4F<<1.

posted by Ad van der Weiden 02 Oct 2014

Assigned to Ivan Jajcevic 10 years, 12 months ago.

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