User manual

Protocol Analysis
R&S
®
Scope Rider RTH
122User Manual 1326.1578.02 ─ 04
Figure 7-1: I2C write access with 7-bit address
Address types: 7-bit and 10-bit
Slave addresses can be 7 or 10 bits long. A 7-bit address requires one byte, 7 bits for
the address followed by the R/W bit.
A 10-bit address for write access requires two bytes: the first byte starts with the
reserved sequence 11110, followed by the two MSB of the address and the write bit.
The second byte contains the remaining 8 LSB of the address. The slave acknowl-
edges each address byte.
Figure 7-2: 10-bit address, write access
A 10-bit address for read access requires three bytes. The first two bytes are identical
to the write access address. The third byte repeats the address bits of the first byte and
sets the read bit.
Figure 7-3: 10-bit address, read access
Trigger
The R&S RTH can trigger on various parts of I²C messages. The data and clock lines
must be connected to the input channels, triggering on math and reference waveforms
is not possible.
You can trigger on:
●
Start or stop condition
●
Repeated start condition
●
Transfer direction (read or write)
●
Bytes with missing acknowledge bit
I2C (Option R&S
RTH-K1)