User manual

POSCOPE4 AND MEGA1+ MANUAL
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I2C DECODER
Inter – integrated circuit simplifies the hardware part of electronic devices. It consists of only 2 wires.
One is used for clock synchronization, the other one is for data transfer purposes. On each I2C bus
you will find one master and multiple slaves. Most I2C busses work on frequencies up to 100 kHz,
which can go higher if needed. I2C mostly uses 7-bit addresses which are actually 8-bit because the
first bit describes whether the Master is reading or writing to the slave address. Mega 1 has the
ability of decoding 8 I2C busses. Each bus can hold up to 128 devices, therefore the Mega 1 can
connect up to 1024 devices.
To see how I2C decoder works, you can use our PoKeys controller, connect it to PoSensors board and
tap into the clock and data lines of i2c bus. They can be connected to any input of the logic analyzer
port.
Connecting PoScope Mega1 I2C decoder to PoSensors
To decode an I2C bus, go to PoScope 4 application. With device set to digital mode and logic analyzer
display open, click the Analyze button. In order to assure quality measurements, note that sampling
rate has to higher than the signal frequency / bus clock rate. I2C is by default 100kBits/s (different
speeds are supported) so we suggest you to setup sampling frequency to 500kS/s and set PoScope4
for capturing. After a second or so (so the buffers will be full) press Analyze button to switch to
analyze.