ColdFire couldn't be tested at a Jtag chain with other devices.

[Coolz]

Hello everyone,

The project I am working on for my company needs to test a BGA Coldfire 5485 with Boundary Scan ( IEEE-1149.1) or JTAG. After pulling MTMOD0 high and only one device itself in the chain, I was able to run Boundary Scan test on it without any problem. However, after I attached it at the end of another JTAG chain on the board including one Xilinx FPGA and two Intel Ethernet chips. The Boundary Scan chain even couldn't be recognized. All the wirings are right. Put scope to look at it. There is something on Coldfire pin A15 (TDI), but nothing coming out of pin D17 (TDO). It seems Coldfire doesn't like to be in a JTAG chain with other devices.

Does anyone have any experience on this?

Thank you.

[J_rg]

We're doing this with a 5474 and two other JTAG devices without any problems. However it is important, that the 5474 is the first device in the chain if you want to use BDM. And check if there is a pullup on MTMOD0 and MTMOD1 through 3 tied to GND.

Regards,
Jörg

[Bass]

HI,

  I am also facing the same problem with MCF5485 if I use in JTAG chain with other device.

 Could anybody us to solve the problem.

[DavidS]

Hi Coolz,

Is your system configured like the following example:

http://www.engr.udayton.edu/faculty/jloomis/ece446/notes/jtag/jtag1.html 

Can you take the ColdFire device out of the scan chain and have the rest of the device working properly?

Are your signals (espcially TCK and TMS) meeting signal level requirements?

Regards,

DavidS