General purpose embedded protocols, General purpose embedded protocols overview, Uart – Teledyne LeCroy Serial Data Debug Solutions User Manual
Page 53: Rs-232, Using the i2cbus option, Using the i, Cbus option overview, Operator's manual
Operator's Manual
919586 RevA
53
General Purpose Embedded Protocols
General Purpose Embedded Protocols Overview
I
2
C
is a standardized protocol created by Philips with a documented technical specification.
NXP (formerly Philips Semiconductors) provide a full description of the standard
Number of Lines
Data rate
Synchronous or Asynchronous
2
Up to 3.4 Mb/s
Synchronous
SPI
was popularized by Motorola but is not standardized, per se - there are a variety of variants with the
differences characterized by how data is clocked, whether data is MSB or LSB format, and whether it is multi-
slave or single-slave.
While the SPI has no formal standard, information is often included in the technical documentation for the
microprocessor supporting the protocol.
Number of Lines
Data rate
Synchronous or Asynchronous
3
Up to ~50 Mb/s
Synchronous
UART
is a generic backbone for many proprietary serial data protocols (too numerous to mention) each with
different physical layers.
UART has no formal standard. The protocol evolved from mechanical rotating teletypewriter devices. Formats
were formalized with the advent of the first electronic computers.
Number of Lines
Data rate
Synchronous or Asynchronous
1
Up to 1 Mb/s (typical)
Asynchronous
RS-232
is a special case of UART, with a more defined protocol and specific physical layer.
The physical layer is defined in the Electronic Industries Association (EIA) EIA-RS-232-C and the
Telecommunications Industry Association (TIA) TIA-232-F. Its protocol layer is not specified; however, UART is
commonly implemented. Resources can be found at
and
Number of Lines
Data rate
Synchronous or Asynchronous
1
Up to 57.6 kb/s (typical)
Asynchronous
Using the I2Cbus Option
Using the I
2
Cbus Option Overview
Both I
2
Cbus D and TD options contain powerful software algorithms to extract serial data information from
physical layer waveforms measured on your oscilloscope. The extracted information is overlaid (annotated) on
the actual physical layer waveforms, and color-coded to provide fast, intuitive understanding.
The I2Cbus TD option contains a very powerful and flexible trigger, but it is also very easy to set up for basic
triggering. The I
2
Cbus TD option contains a conditional I
2
C DATA trigger to select a range of DATA values to
trigger on, not just a single DATA value.