The port sniffer is a microcontroller module  to be inserted in the connections between a microcontroller (or an FPGA, for example) and the attached peripherals. Its main purpose is logging and visualization. In other words, it is (connected to a personal computer) a very basic logic analyzer.

It is some kind of a probe pod. The microcontroller can observe the signal lines. It can also inject signals, or it can be programmed as a substitute, emulating the peripheral devices attached to the target system.

One module can inspect up to 24 I/O signals. If more signals are to be observed, some modules can be connected to a multiprocessor hub (active or passive).

1 – inbound port signals; 2 – outbound port signals; 3 – test points; 4 –  RS-232 interface; 5 – reset and clock signals for single-stepping the target system; 6 –  header for multiprocessor connection (downstream / slave); 7 – header for SPI programming. The SPI port can be used alternatively to attach peripheral controllers (e.g., Ethernet) or serial memory.

September 26, 2014

The web page has been set up.

Download a schematic.