Flashing RM4x and communicating

Hi Sie,

I am not sure I can answer because the answer depends a lot on the design of the board.

On a lot of our boards, you can have the external emulator connected and the on-board emulator (xds100) would detect this and disconnect itself from JTAG.  But you may still want to use the serial port on this link or just power the board from this link.    Is that your question?

The detection of the external emulator (XDS220) is normally done by pulling up one of the pins on the emulation header that is GND when the emulator is connected.    For example see  sheet 3:

If your board doesn't have something like this then it may be unable to disconnect the XDS100 automatically when you plug in the external emulator.

Hello Anthony,

thank you for your answer.

I have this boards:

www.ti.com/.../tmdsrm48hdk

http://www.ti.com/tool/tmdxrm42hdk

I want to flash over the JTAG Header, and communicate over the usbmini connector.

The Problem is when the JTAG Header and the usbmini are both connected i can not Flash over the JTAG Header.

In the meantime i found a way to communicate over usbmini and let the JTAG Header connected.

I removed resistors from the boards.

At the RM48 board i removed R251-255 and R260-262.

At the RM42 board i removed R110-117.

But I am not sure if this is the correct solution.

With this solution I can communicate with the board over usbmini, and Flash the board over JTAG Header (J3 at RM42 and J4 at RM48).

Hope this text is more clear what I want.

Regards

Hi March,
You shouldn't need to remove those resistors, if the XDS220 is pulling down the JTAG Select (pin 8 on the 20 pin jtag header) on the RM42 board.
You might check that. On the RM42 board in particular there is an LED DS1 that shows that the external JTAG is selected.
DId you have to build your own adapter to go between the board and your emulator? If so did you make sure that pin 8 is grounded (on the 20 pin headers?)

Hello Anthony,

thank you for your answer.

I am currently looking at the schematics of both boards, and on both schematics there are 10k resistors.

Normally if the XDS220 is connected then the voltage on both boards on pin 8 should be 0, correct?

If the voltage is not 0, what could be the reason for this?

I am using the Adapter which was delivered with the XDS220 Adapters.

Regards

>>Normally if the XDS220 is connected then the voltage on both boards on pin 8 should be 0, correct?
Yes, basically. Could be a bit above 0V if it' not hard-grounded.
If the voltage is not 0, what could be the reason for this?
If it's a low voltage (0.2V ish) this could be ok.
If it's close to 3.3V then there's probably something wrong w. the adapter or the emulator cable.

Hello Anthony,
the voltage on pin 8 is 0V.

The LED DS1 on the eval boards is on.

Any idea what I can also do?

Regards

Hi Marsch,

If you haven't changed the XDS220 setup between resistors on and off, then I'm not sure what to tell you other than work with what's working (resistors off). You shouldn't have to have them off, but at this point it probably isn't worth debugging further to find out why unless for some reason you want to keep the resistors on.