Transport Layer; I2C Transport - NEONODE zForce AIR Touch Sensor User Manual

zForce AIR® Touch Sensor User's Guide
F0 20 40 02 02 00 A0 1A
where the first "II" and the following bytes up to and including "JJ" are from the first touch, and the second "II" and
the following bytes up to and including "JJ" are from the second touch.
Three Touches
A packet that contains three Touches will look like:
F0 2B 40 02 02 00 A0
YY YY GG HH JJ 58 02

7.3.3 Transport Layer

I2C Transport

Sensor Address
The Slave I2C address of the sensor is 0x50 (7-bit).
When sending the 7-bit address, still 8 bits are used. The extra bit is used to inform the slave if the master is writing
to it or reading from it. If the bit is 0 the master is writing to the slave. If the bit is 1 the master is reading from the
slave. The 7 bit address is placed in the upper 7 bits of the byte and the Read/Write (R/W) bit is in the LSB (Least
Significant Bit).
The resulting address bytes are 0xA1 (Read) and 0xA0 (Write).
Reading Sequence
The sensor does not communicate using registers / memory accesses, so the STM32 documentation is not
applicable.
To maximize performance and minimize the load on the I2C bus, the host is expected to read data in a certain
sequence. This ensures a stable and reliable communication. The I2C read sequence is specified below.
https://support.neonode.com
42 09 II VV XX XX YY YY GG HH JJ
25 42 09 II VV XX XX YY YY GG HH JJ
TT TT
42 09 II VV XX XX YY YY GG HH JJ
42 09 II VV XX XX YY YY GG HH JJ
Software Integration
58 02 TT TT
42 09 II VV XX XX
41