PK-HCS12E128 User's Manual
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Background Debug Module (BDM)
All MCUs in the HCS12 family contain a single-wire background debug interface which
supports in-circuit programming of on-chip non-volatile memory and sophisticated non-
intrusive debug capabilities. This system does not interfere with normal application
resources. It does not use any user memory or locations in the memory map and does not
share any on-chip peripherals. The background debug module (BDM) uses a single-wire
communication interface to allow non-intrusive access to target system memory and
registers.
PK-HCS12E128 features a USB-to-BDM circuitry which allows the host PC to communicate
to the microcontroller through a standard USB cable.
PK-HCS12E128 Board Layout
The PK-HCS12E128 board has the following hardware features:
1.
A “USB to BDM Interface” section.
It contains the circuitry needed to electrically and
logically translate BDM-like commands sent by the host PC through the USB cable to
the BDM interface of the microcontroller. The PK-HCS12E128 board is powered (at 5 V)
by the USB bus.
2.
A “Demo” section.
It features a RESET push-button, two user push-buttons, a
potentiometer and eight user LEDs, plus a LED connected to a DAC output pin.
3.
A “MCU” section.
It contains a soldered, 112-pin MC9S12E128 device (in QFP
package) with connectors to access the I/O pins of the microcontroller for expansion
prototyping. A 16 MHz crystal oscillator (in Colpitts configuration) is provided, and the
microcontroller is configured to work in single-chip mode (MODA = MODB = 0).
4.
A “Prototype” section.
You can wire your own circuit here. The prototype section
features both a standard, thru-hole area (for mounting traditional components) and a
SMD area (for soldering SMD components in SOIC package).
