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I2C
The bus3
§All 3 in brief01Why a bus02Who starts the talk03The clock
Addresses3
§All 3 in brief04Addresses05Scanning the bus06Two chips, one address
Talking to a chip2
§All 2 in brief07Registers: the drawers inside08Reading a temperature
The two wires4
§All 4 in brief09Why pull-up resistors10How big a pull-up11Too many pull-ups125 V and 3.3 V
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Fundamentals/I2C/Talking to a chip
Chapter · I2C

Talking to a chip

The numbered registers inside a chip, and one whole read of a temperature, a piece at a time.

2 articlesabout 9 minutesNo board required
  1. 07Registers: the drawers inside4 minAn address picks a chip; a register picks something inside it. The controller writes a register's number to move the chip's pointer, and every read returns whatever the pointer is at.
  2. 08Reading a temperature5 minOne read of an LM75 is a write of the register number, a repeated start, and two bytes back. Put the bytes together as a signed number, divide by 256, and that is the temperature in degrees.

Start at 07 and read down — the order is the order things get easier in. Or take the one with your part in it; every article stands on its own, and links back to whatever it needs.

← Previous chapterAddresses3 articlesNext chapter →The two wires4 articles
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