The EmbeddedICE logic in ARM cores such as ARM7TDMI and ARM9TDMI contains a debug communications channel. This enables data to be passed between the target and the host debugger using the JTAG port and a protocol converter such as Multi-ICE, without stopping the program flow or entering debug state. This chapter describes how the debug communications channel can be accessed by a program running on the target, and by the host debugger.

ADS provides the following methods of accessing the debug communications channel: