To program and debug the HC12 and HCS12 controller you need a BDM tool. I was afraid that I could destroy my inDART HCS12 BDM Pod from www.softecmicro.com if use it with my selfmade boards. So I decided to get a cheaper one. By now there are a few BDM tools you can build yourself at home. As there are Podex using an Atmel AVR controller, the BDM Loader using a MC68HC908QT1 and TBDML. Because I never had done anything with AVR controllers I decided not to use this one. Podex is supported by GCC and GDB by using the Kevin Ross protocol. The BDM Loader only works with an own software and the documentation is in spanish. There is an english version of the BDM loader Software and the translation of the documentation is in progress. TBDML is supported by Codewarrior an GCC/GDB too. Having a USB interface you can use on a PC without a RS232 inerface. This s why I decided to use TBDML.

Based on the schematics and the software from www.freegeeks.net I built my own BDM tool. The schematic differs a little from the original, because I already have a programmer for HC08 controllers. I left the MAX232 away and just soldered the header for the programmer on the board. Not having a 74HC125 at and, I used a 74HCT125. The 74HCT125 must be used with 5 Volt levels. Using it at 3,3 Volts I got errors. The original controller for TBDML is the 68C908JB8, which is availible in a 20 pin DIP package. The disadvantage is that the MC68HC908JB8 is clocked with only 6 MHz. The MC68HC908JB16 is clocked with 12 MHz and nearly twice as fast. The version with the 6HC908JB8 can be used with quartzfrequencies up to 20 MHz, so that maybe no problem. A software version supporting the MC68HC908JB16 is availible too at www.freegeeks.net in the download area. I don´t know what will happen to www.freegeeks.net in the future. The forums already went to Freescale and can be accessed at http://forums.freescale.com/. The documentation and the software ia downloadable at Freescale too. You can find it in the 16 Bit Commnity Files section. Because www.freegeeks.net is offline and Freescales site is sometimes hard to navigate I decided to put the TBDML distributions I used here on this page. The firmware for the JB16 can be found here tbdmljb16.zip. The other Distribution used is here distr_11h.zip changes are only made on the PC side, so the JB16 firmware is not changed.



One advantage over my old BDM Pod is the compatibility to the older HC12 controller. The Softecmicro Tool only suports the HCS12 controller. So I can use the TBDML for my HC12 Welcome Kit too. Codewarrior is supported in version 4. This was the version for the HCS12X controller. The two HCS12 versions are now merged in Codwarrior V4.5. Last thing to mention is the schematic of my modified TBDML which comes here.