MC68332: Function of the TSC Pin

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

MC68332: Function of the TSC Pin

1,478 Views
hubertus
Contributor I
A few days ago, i constructed a PCB for the MC68332. It contains only 512k RAM and some LEDs and switches; I built it only for testing the MC68332 (this is my first project with this controller).
Now, I wondered, why BDM doesn't work (I use Windows XP). I tried an very old machine with DOS, but there BDM still didn't work. BD32 hangs every time I start it!
Somebody told me, that I have to connect TSC to Vcc. On my board, I routed it to GND! Does this have an effect on the function of BDM?
Is there an example design for the MC68332 controller?
Labels (1)
0 Kudos
Reply
1 Reply

499 Views
macl
Senior Contributor I
Pulling TSC to ground enables a factory test mode.  I'm not sure if BDM will work in that mode.  Here's an excerpt from the app note M68331_332TUT.pdf (freescale.com) that talks about TSC.
 

TSTME/TSC —

The inactive state of this pin is five volts. Pulling it low enables special test mode, but the MCU cannot enter test mode unless the state of a bit in one of the test mode registers is changed by the software. Although this should happen only if the software is corrupted, to prevent entering special test mode, put a 10 KW pull-up resistor on this pin. Special test mode is generally used only for factory testing, although there are certain circumstances, such as debugging TPU microcode, in which a limited subset of test mode capabilities are available to users. Driving this pin to approximately 1.6 times VDD causes the MCU to place all output drivers in a high-impedance state, isolating the MCU from the rest of the system.
0 Kudos
Reply