TMS320F28377S: DO-178C compliance of bootstrap and ADC calibration functions

Hi Francois,

We are working on the response to your query. It may take some time due to spring break vacations.

Just wanted to assure you that we are working on it and will be replying with detail as soon as possible.

Regards,

--Ashish

Hi Francois,

Thank you for your patience.

TI code inside the ROM gets executed only during boot time and during application run time() these are not used.

To be able to confirm correct device state after boot-up and before entering application code it is expected that Pre-operational checks are required to be executed by customer.

Below is the text and diagram from Safety Manual for TMS320F2837xD/S and TMS320F2807x

Pre-operational - Transfer of control from boot code to customer code takes place during this phase. Application specific configurations (for example, clock frequency, peripheral enable, pinmux, and so forth) are performed in this phase. Boot time self-test/proof-test required to ensure proper device operation is performed during this phase.

6.4.8 Power-Up Pre-Operational Security Checks

During the device boot, it goes through various phases. In the pre-operational phase (before starting the application), the application code is expected to perform a set of checks to ensure correct initialization of device security which includes checks to confirm correct link-pointer settings, CRC lock setting, correct partitioning of secure RAM blocks and Flash sectors (Grab Bits), setting for execute only protection for secure RAM blocks and Flash sectors, correct partitioning of the CLA and Flash Bank2 and correct settings for boot configuration. Before starting the execution of downloaded code user should check the integrity of the code using CRC function. Once pre-operational checks are successfully completed with expected results, the device can enter the application phase.

Specifically for 3 ADC calibration functions, which are allowed to be called by application code, please find below explanation. 

1. Device_cal(),

• This function copies the TRIM values from OTP to ADC registers.
• We plan to describe this function in detail in next TRM release
• Customer can either implement their own function based on description, or verify the copy completion themselves as measure to verify the correct functioning of this code.

2. CalAdcXINL(), GetAdcOffsetTrimOTP()

• Regular functions in support files.(C code). Already source code available to customer

Regards,

--Ashish

Hello Ashish,

Thank you. I see we could help for the ADC-related functions during the application runtime.

But there remains an issue which is the execution of the boot ROM code execution (warm boot in the above diagram). The DO-178C compliance creates constraints about all the software that runs on the system, including the manufacturer's ROM code. I see the F2837xD/S Safety Manual refers to a device-specific boot ROM specification. Is this something we could provide under NDA?


Thanks,
François.

Hi Francois,

ROM Code and Peripheral Booting is covered under TRM for TMS320F2837xD.