TM4C129 BOOTCFG

Scott McFarland

Intellectual 840 points

Other Parts Discussed in Thread: EK-TM4C1294XL

Custom board using TM4C129

CCS Version: 5.5.0.00077

ICD interface is TM123G launch pad.

The BOOTCFG test for the TM4C129 does not function the same as the TM4C123.

I am programming BOOTCFG to 0x00002C12.

Which should test GPIO_B3 for a low state to enter the BOOTLOADER or run from FLASH as long as location 0x00000004 is not 0xFFFFFFFF.

The device does in fact enter the boot loader when GPIO_B3 is low at reset, however when GPIO_B3 is NOT low at reset the device is HUNG. It is not executing from FLASH. Location 0x00000004 is equal to 0x0000A83D so why is it not running from FLASH?

This worked fine on the TM4C123 device.

over 11 years ago

0 Amit Ashara over 11 years ago

TI__Guru**** 244400 points

Hello Scott,

Questions on the same

1. Which TM4C129 and TM4C123 parts were being used

2. When you mention that it was "NOT" low, then does it mean that it was driven high or was the input to the device left floating?

3. In case of the latter what was the polarity of the PB3 pin when left floating.

4. What was the interface that you are using for ROM Boot Loader Usage: UART, USB, etc.

Regards

Amit

0 Scott McFarland over 11 years ago in reply to Amit Ashara

Intellectual 840 points

Part in question: XM4C129ENCPDTI2

Part(s) which work correctly: TM4C1230H6PMI7, TM4C1230H6PMI

Yes GPIO_B3 is driven high through a 10K resistor. 10K resistor was also used on TM4C1230H design.

BOOTCFG initiates the ROM Boot loader. I am using UART 0.

But the problem is that is NOT SUPPOSED to invoke the boot loader if GPIO B3 is high.

0 Amit Ashara over 11 years ago in reply to Scott McFarland

TI__Guru**** 244400 points

Hello Scott,

The issue is that programming the BOOTCFG Reserved bits to 0 may have unwanted side affects, I was able to reproduce the issue on my side. However after changing the BOOTCFG to 0x2CFE instead of 0x2C12 (so that the Reserved bits are kept as 1) allowed the program to execute the same manner as on TM4C123.

Regards

Amit

0 Scott McFarland over 11 years ago in reply to Amit Ashara

Intellectual 840 points

Thanks, that worked for me also.

0 Amit Ashara over 11 years ago in reply to Scott McFarland

TI__Guru**** 244400 points

Hello Scott,

Do make sure that reserved bits are maintained by the code (if you are not using TIVAWare)

Regards

Amit

0 Daniel Haslimann over 10 years ago in reply to Amit Ashara

Intellectual 810 points

Hi all

I have just noticed the same behaviour on a XM4C1294NCPDT12 (on the EK-TM4C1294XL board). Reserved bits in BOOTCFG have to stay 1, otherwise the device does not boot anymore. I could not find any information on that in the Errata, and I don't think the description about BOOTCFG is clear on that.

This thread saved my day, Thanks!

Daniel

0 Amit Ashara over 10 years ago in reply to Daniel Haslimann

TI__Guru**** 244400 points

Hello Daniel,

That is why the data sheet mentions what the reserved bits must be maintained as... The API's also take care of the same.

Glad it saved the day...

Regards

Amit

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TM4C129 BOOTCFG