Freescale Semiconductor SC140 specifications Main Capabilities of the EOnCE Module, EOnCE Signals

Main Capabilities of the EOnCE Module

4.3 Main Capabilities of the EOnCE Module

While the JTAG port provides board test capability, the EOnCE module provides emulation and debug capability. The EOnCE module permits full-speed, real-time, and non-intrusive emulation for a target system or a SC140 development board. This section describes the environment in which the EOnCE module is used for debugging a real-time embedded application. Figure 4-6 shows a typical debug environment where the core resides in a target DSP system.

		Target DSP		Host
				Computer
Memory				Debugging
				Software
Control
Data	EOnCE
			EE
				Debugging
		7
SC140				Hardware
	JTAG
Core
	Interface
	TCK TDO TDI	TRST TMS	EOnCE Signals
			JTAG Signals

Figure 4-6. Typical Debugging System

4.3.1 EOnCE Signals

The JTAG signals TCK, TDI, and TDO are used to shift data and instructions in and out (see Table 4-1 on page 4-2 for a description of the JTAG signals). For emulation of specific functions, six dedicated EOnCE event signals (EE0–EE5) are available as well as one data event (EED) signal and two event counter (EC) signals.

The two event counter signals EC0 and EC1 allow the event counter to count off-core events such as cache hits/misses, memory contention, external wait-states, etc. These inputs are assumed synchronous to the core clock and support a counting rate up to the core frequency. EC0 and EC1 use is derivative-dependent.

The EE signals can be connected to any on-chip peripheral block such as DMA or TIMER as well as off-chip. This enables an external device to intervene asynchronously in the SC140 debugging process, or to serve as an indication of the events occurring inside the DSP device. Some of these signals have multiple functions programmed by the EE Signals Control Register (EE_CTRL). See Section 4.7.6, “EE Signals,” for further information.

4-10 SC140 DSP Core Reference Manual