D E M O 9 S 1 2 X D T 5 1 2
J U L Y 1 8 , 2 0 0 8
9
DEVELOPMENT SUPPORT
Application development and debug for the target MC9S12XDT512 is supported through the
BDM interface. The BDM interface consists of an integrated USB-Multilink BDM and a 6-pin
interface header (BDM_PORT) to connect a HCS12 BDM cable.
Integrated BDM
The DEMO9S12XDT512 board features an integrated USB-Multilink BDM from P&E Micro-
computer Systems. The integrated USB-Multilink BDM supports application development and
debugging via background debug mode. All necessary signals are provided by the integrated
USB-Multilink BDM. A USB, type B, connector provides connection from the target board to
the host PC.
The integrated USB-Multilink BDM pr5V power and ground to target board eliminating
the need to power the board externally. Power from the USB-Multilink BDM is derived from the
USB bus; therefore, total current consumption for the target board, and connected circuitry,
must not
exceed 500mA
. This current limit describes the current supplied by the USB cable to
the BDM, target board, and any connected circuitry. Excessive current drain will violate the
USB specification. Damage to the host PC USB hub or the target board may result.
The communications speed over the USB bus is controlled by the USB_SPEED header.
When shipped from the factory, the DEMO9S12XDT512 is configured for high-speed opera-
tion. If the user encounters a communication failure, USB communication speed may be re-
duced by setting this option jumper to Full.
Figure 1: USB_SPEED Option Header
USB_SPEED
Configuration:
HIGH
1
2
3
FULL
1 – 2: Selects USB High-speed communications
2 – 3: Selects USB Full-speed communications
CAUTION:
Do not allow total current drain to
exceed 500mA
when powered from the
USB-Multilink BDM .
BDM_PORT Header
A compatible HCS12 BDM cable can also attach to the 6-pin BDM interface header
(BDM_PORT). This header is not installed in default configuration. The figure below shows
the pin-out for the DEBUG header
Figure 2: BDM_PORT
MODC/BKGD
1
2
GND
3
4
RESET*
5
6
VDD
See the HC12 Reference Manual for
complete DEBUG documentation
NOTE:
This header is not installed in default configuration.
