9S12DJ64 oscillator and BDM question

[68HC912B32Guy]

Hi all,

I successfully designed and realized a project using an older HC12 processor back in 2003, so I am now trying to use the 9S12DJ64 to take its place.  I have two questions:

1)  I am using a Pierce oscillator on my 9S12DJ64 with an 8 MHz crystal (R_B=10M, with bypass caps into EXTAL and XTAL both at 22pF),  PE7 driven low, VDDPLL bypassed to GND with 100nF.  The PLL components across XFC and VDPLL (using the Motorola filter application) are 2.7kohm in series with 4.7nF and those in parallel with a 470pF.  However, my 68HC912B32 eval board will not take control of my 9S12DJ64 via BDM, so I suspect the 9S12DJ64 oscillator is not functioning.  Is there anything I should look out for?  I don't need the PLL actually, so if I can get the 9S12DJ64 running at 8 MHz bus without it, I'd be pleased.

2)  Can an 8 MHz bus 9S12DJ64 be controlled via the BDM by a 68HC912B32 eval board (also running at 8 MHz bus) with D-Bug12?

I attached the board schematic.  You can see how simple it is.  I'm only using 7 pins for I/O on the entire processor.

Thank you.

[mculater]

Can't Communicate With Target CPU

1.) Set Target Speed (16000 KHz)
2.) Reset Target
3.) Reattempt Communication
?

I got the above display when using an old 912B32-based pod with a 9S12DP512 target.  Changing the target speed to 8000 should do the trick for your config, but you may need pulldowns on MODA and MODB pins, just to ensure your MCU is in single-chip mode.  Otherwise, the BDM will not sync up...

Best regards,

Carl Barnes

www.technologicalarts.com

Check out Esduino12, an S12-based Arduino-compatible!

[68HC912B32Guy]

Turns out I overlooked a pull-up resistor on the reset line when I ported my old board over. Now my board is alive with a hastily placed pull-up.