Freescale MC9S12x Microcontroller In-Circuit Emulation Solution

The In-Circuit Emulator emulates the target CPU, which is removed from the target, as good as possible. Beside the CPU, additional logic is integrated on the POD. The amount of additional logic depends on the emulated CPU (e.g., Freescale MC9S12x) and the type of emulation. A buffer on a data bus is always used (minimal logic) and when rebuilding ports on the POD, maximum logic is used.

 

In-Circuit emulation tool setup: iC3000 base unit + ActivePRO POD for Freescale MC9S12x

 

As soon as the POD is connected to the target instead of the CPU, electrical and timing characteristics are changed. Different electrical and timing characteristics of used elements on the POD and prolonged lines from the target to the CPU on the POD contribute to different target (the whole system) characteristics. Consequentially, in worst case signal cross-talks and reflections can occur due to bad target connection, capacitance changes, etc. Beside that, pull-up and pull-down resistors are added to some signals. Pull-up/pull-down resistors are required to define the inactive state of signals like reset and interrupt inputs, while the POD is not connected to the target. Because of this, the POD can operate as standalone without the target.