MSPM0L1106: Is the ROM BSL I2C0 supported on the 16-pin parts (RTR) that share NRST with the I2C_SCL0 pin?

Derek DeBusschere

Part Number: MSPM0L1106

Tool/software:

The linked forum posts indicates that the BSL *does not* disable the NRST automatically in order to enable the use of the default BSL_I2C_SCL0.

Is this answer confirmed to be correct?

The datasheet and TRM have no clear warnings about this, and this isn't obvious when prototyping with a launchpad using the 32-pin device. That seems like a major oversight.

Thank you

e2e.ti.com/.../mspm0l1105-how-can-host-invoke-the-bsl-when-the-nrst-pin-is-used-for-i2c-in-16pin-package

4 months ago

0 Dennis Lehman 4 months ago

TI__Guru 71216 points

Hi Derek,

I will take a look.

0 Dennis Lehman 4 months ago in reply to Dennis Lehman

TI__Guru 71216 points

Hi Derek,

Well first I found this in the datasheet, where on 16 and 20-pin devices the NRST is muxed with PA1.

But that doesn't answer the question if NRST is automatically disabled by the BSL. I found the engineer who developed the BSL and will ask him.

0 Derek DeBusschere 4 months ago in reply to Dennis Lehman

Prodigy 20 points

Hi Dennis,

Yes, thank you, I agree the pin is muxed. I'm just surprised (if accurate) that exact footnote wouldn't include a warning that this makes the default i2c bsl mode unusable without some other method of programming blank devices. It looks like an option is to add an i2c0 bsl plugin and make the init code immediately disable the nrst, but that requires a different initial programming method (uart bsl or SWD) and reserving a small part of main flash for the plug-in code. It is just unclear if a BSL_INVOKE somehow temporarily disables NRST.

0 Dennis Lehman 4 months ago in reply to Derek DeBusschere

TI__Guru 71216 points

Hi Derek,

I had quite a number of our HW and SW engineers involved on this one and the conclusion is: Add the plugin interface in Flash with NRST Pin disabled in BSL_PI_I2C_init().

See attached.

0 Derek DeBusschere 4 months ago in reply to Dennis Lehman

Prodigy 20 points

Hi Dennis,

Okay, thank you (and the Ti team) for the clarification and the clear workaround with the tested confirmation. We will go with the init disable of the plug-in and use SWD for initial configuration.

I'd also recommend that TI expand that shared pin datasheet footnote to clarify / warn about the loss of the purely ROM I2C BSL.

Arm-based microcontrollers

Arm-based microcontrollers forum

MSPM0L1106: Is the ROM BSL I2C0 supported on the 16-pin parts (RTR) that share NRST with the I2C_SCL0 pin?