Midas Neun Soldaten: @ Optically Isolated BDM Interface for the S08/S12 Microcontrollers

Purpose

I have got old USBBDM Multlink tool from my former staff and have played some projects using this tool.
Sometime I was mistake to notify the external MCU project board's Power-Ground isolation against the
external DC power adaptor but would damaged my laptop's USB port neither the BDM-ML tool.
Well, it happened twice and I need to ask my friend to repair my damaged USB port on my NB.

So the purpose of this note is to explain the modification of the FSL S08/S12 Multilink BDM Interface.
The complete project consists of the P&E BDM Rev-C and an opto-isolated daughter board.
The completed assembly, both PCB’s, fit into the original ML-BDM case.

BDM Rev-C

BDM Rev-B

Installing the jumper on the Multilink BDM board

The jumper is to provide the host side of the opto isolated board with 5V to power the opto couplers
and provide signal.
* Open the Multilink case and remove the PCB.
* Unplug the ribbon cable attached to header J2.
In following figure, solder a jumper wire to pins 3 and 16 on connector J3.

Opto Isolated BDM board
The opto isolated board can be used with the Multilink Rev B (blue) and Rev C (maroon case) interface
devices. This opto isolated board plugs into the BDM Multilink board upside down.

Assembling the Multilink board to the opto isolated board
Turn the opto isolated board upside down and plug the connector J1 onto the Multilink BDM board to header J2.
Plug in ribbon cable onto connector J2 on the opto isolated board.
Make sure the red strip on the ribbon cable is on the same side as the white dot on the opto isolated board J2
header. Re-assemble the case and test the Multilink interface.
When the interface is plugged into the USB port, the blue and the yellow LEDs will illuminate.
This is different than the unisolated Multilink BDM because the yellow light only will illuminate when
target power is applied.

Opto Isolated BDM board Schematic

Optocoupler Component U1, U2 in Schematic
The optocoupler used in the design was the Agilent Technologies HCPL-0630 device.
I purchased some pcs from Taiwan KuaHwun Market with cost of $ 80TWD/pcs.
It has a typical data transfer speed of 10M-Bd and is intended for use in MCU systems.
This optocoupler design provides maximum AC and DC circuit isolation while achieving TTL compatibility.

Opto Isolated BDM Board Layout Layers

Top Copper Layer