JTAG

From S1MP3 Wiki

JTAG is not supported by ATJ20xx devices.

JTAG could not work properly with our pinout because the TMS pin would be ICEEN, which must be low during the whole ICE working flow.

About JTAG

JTAG is a debugging purposes circuit (or circuit serie) present on all modern embedded systems; when interfacing correctly through JTAG you can control the whole MCU (Micro Controller Unit) in a non-invasive mode.

Each JTAG interface comes in with a specific BSDL file which defines its basic parameters like IR (Istruction Register), DR (Data Register, maybe more than one) and BSR (Boundary-Scan Register) bit sizes; having such a specification, you can easily control the device through JTAG.

Related Pages

• ICE, the real In-Circuit emulator behind ATJ20xx devices
• wikipedia JTAG article