TMS320F280049: Using default boot pins for can boot mode

David Baltaro

Part Number: TMS320F280049

Hello,

We plan to boot from CAN on a 280049 device, without programming the OTP boot related registers (Z1-OTP-BOOTPIN-CONFIG , Z1-OTP-BOOTDEF-LOW / Z1-OTP-BOOTDEF-HIGH)

- The default pins to select boot modes are GPIO24 and GPIO32. These Pins will be pulled-up.

- The default CAN boot mode uses CANTXA on GPIO32 and CANRXA on GPIO33.

So could You please confirm that the same pin GPIO32 is usable for both boot mode selection and CAN dataloading ?

if we force a logic 0 at reset time (GND) on GPIO32 pin, the DSP will branch to bootrom and will wait for CAN communication on GPIO32 and GPIO33 pins ?

Do we have to separate the GPIO32 signal from CAN transceiver when initiating the boot process ?

The GPIO32 input pin at boot mode with become the CANTX output after entering CAN bootloader. Is specific electronic needed for this ?

Thanks by advance

David

over 4 years ago

0 Baskaran Chidambaram over 4 years ago

TI__Genius 17370 points

its better to avoid using same pin for both boot selection and CAN.

Can you check if you can use different set of pins for CAN communication ?

0 David Baltaro over 4 years ago in reply to Baskaran Chidambaram

Prodigy 150 points

Usage of different set of pins is possible, but we don't want to program OTP.

Is it possible to choose different pins for CAN without programming OTP ? I think not.

Why is it better to avoid using same pin for both boot selection and CAN ?

why provide CAN boot among the 4 defaults mode (RAM, FLASH, SCI, CAN) if CAN mode cannot be used as is, in default configuration ?

0 Baskaran Chidambaram over 4 years ago in reply to David Baltaro

TI__Genius 17370 points

Apologies for the delay in response.

I was cross checking again with internal experts and got confirmation as NOT to use the same pin for boot mode selection and CAN communication.

The pin 32 needs to be pulled low to select CAN boot mode. But 32 is the TX pin for CAN. If this pin is low (during boot-mode selection), the entire bus would be driven low. This would confuse the other nodes in the network, prompting them to generate error frames

I see the limitation here and taking this feedback to assign different pin for default mode of CAN bootloader in future devices.

0 David Baltaro over 4 years ago in reply to Baskaran Chidambaram

Prodigy 150 points

I would have preferred another answer but now it's clear.

Thank you

0 David Baltaro over 4 years ago in reply to David Baltaro

Prodigy 150 points

So, among the 4 available modes in default configuration, which is the T.I. recommended bootloader to use with the 280049 if we don't want to program OTP ? SCI ? Is there an application note or a reference design to explain how to connect SCI to trig bootloader mode in this case (maybe using SCI break) ?

Thanks again.

0 Baskaran Chidambaram over 4 years ago in reply to David Baltaro

TI__Genius 17370 points

you can use any of parallel, flash, or SCI boot modes.

I didnt get the 2nd part of your question, can you elaborate - "explain how to connect SCI to trig bootloader mode in this case (maybe using SCI break)"

0 David Baltaro over 4 years ago in reply to Baskaran Chidambaram

Prodigy 150 points

Ok, the main idea is to program the 280049 without using JTAG and in a first approach, without programming OTP.

We want to design a new control board for an avionic fan. The board, equipped with the 280049 will be accessible only by a connector. We want to program the 280049 thourgh this connector. In previous designs (2812, 28335, 28069) we used SCI to control the boot mode of the DSP by sending a break signal on the SCI. A small specific electronic circuit was used to force the correct logic level on boot pin and switch to SCI bootloader mode.The same SCI pins were used to transfer a custom bootloader able to flash the DSP. No need to program OTP to redefine boot modes pins and reasign SCI used pins in this context.

With this new 280049, is there a way to perform the same action ? Is there an application note or a reference design to explain how to access and program a 280049, in defaut configuration boot mode, using the SCI ?

Thanks.

0 David Baltaro over 4 years ago in reply to David Baltaro

Prodigy 150 points

Hello,

No information on this subject ? Should I reopen this question in a new thread ?

0 Baskaran Chidambaram over 4 years ago in reply to David Baltaro

TI__Genius 17370 points

Hi David,

yes its preferable to open new thread for new queries or after the thread is marked as resolved. This helps us to keep track of open threads and respond.

I will check with others internally on your query.

Regards

baskaran