Next-generation in-circuit emulators (such as the MPLAB^® REAL ICE™ in-circuit emulator) and in-circuit debuggers work with devices that have on-chip debug circuitry. Sometimes the actual production device will have this circuitry and sometimes a special version of this device is required or available for code debugging. This special version of the chip, with the suffix -ICE or -ICD, is mounted on a debug header (see figure).