Bootloader

Githin George

Other Parts Discussed in Thread: TMS320F28021

Can any one tell me about the default factory built bootmode for TMS320F28021. Whats happen when the controller powers ON?

Will the GPIO pins affect the bootmode?

Thank You

Githin

over 10 years ago

0 David M. Alter over 10 years ago

TI__Guru 61235 points

Githin,

Per the datasheet SPRS523J, Table 3-6, the bootmode is controlled by the combination of pins GPIO37, GPIO34, and TRSTn. When the emulator is not connected, TSRTn=0. Also, GPIO34 and GPIO37 have internal pullups on them, so they will be high by default (unless the user overpowers the weak internal pulls with external pulls). Hence, the default bootmode is 'GetMode'.

If the GetMode locations in OTP have not been modified by the user, they will be erased (0xFFFF), and this will cause the jump-to-flash bootmode.

Regards,

David

0 Githin George over 10 years ago in reply to David M. Alter

Intellectual 290 points

Hi David,

Thank You for the reply. I have one more doubt. what happens if GPIO37 and 34 is dedicated as input pins or some sensors are connected and reads as LOW. then will it goes to Parallel IO mode.

Thank You

Githin.

0 David M. Alter over 10 years ago in reply to Githin George

TI__Guru 61235 points

Githin,

GPIO37 and 34 are always checked by the bootloader. If you have something connected to them that drives them on way or the other, it will impact the boot mode entered. You need to take this into account when you use these pins for something in your system.

Regards,

David

0 Githin George over 10 years ago in reply to David M. Alter

Intellectual 290 points

Hi David,

Thank You for the reply.

So whenever i powers on the controller, i should take care of these pins in-order to access the flash right?

thank you

0 David M. Alter over 10 years ago in reply to Githin George

TI__Guru 61235 points

Yes.

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Bootloader