AM3703 SYS_BOOT pins

Kyle Mouratidis

Other Parts Discussed in Thread: AM3703

Hi there,

I'm in a situation where my AM3703CUSD100's SYS_BOOT[6] .. SYS_BOOT[2] pins are floating. I have access to SYS_BOOT[1] and SYS_BOOT[0]. Is there a way that I can have the AM3703 latch different pins for the CONTROL.CONTROL_STATUS register on reset, or is there another way to change the boot configuration? Could this be accomplished using JTAG?

over 10 years ago

0 Biser Gatchev-XID over 10 years ago

TI__Guru**** 393215 points

Hi Kyle,

There is no such possibility. CONTROL_STATUS register is read-only and SYSBOOT pin values are latched in it on POR rising edge.

0 Steve Kipisz over 10 years ago in reply to Biser Gatchev-XID

TI__Genius 15510 points

Actually, since this is an AM37xx part, there is a little known feature called Software Booting. Look in the Initialization chapter of the TRM. I have Revision R and the section is 26.4.4.4. On first boot, the sys boot pins are read for booting. You then fill in this structure with a "create your own" boot order and then on a reset, the boot ROM boots using this software order. I used it once a LONG time ago.

Steve K.

0 Kyle Mouratidis over 10 years ago in reply to Steve Kipisz

Prodigy 150 points

Hi Steve, thanks for your reply.

My understanding is that the "create your own" boot order resides in the scratchpad memory, and that this order will take priority over the boot pins if you do a warm reset. Do you know if there is a way to retain this boot order if the device loses power, or if you are stuck rewriting the boot order to the scratchpad when this happens?

Best regards,

Kyle

0 Steve Kipisz over 10 years ago in reply to Kyle Mouratidis

TI__Genius 15510 points

You're stuck rewriting the boot order when you lose power. On a cold boot (after power loss) the sysboot pins are used.

Steve K.

0 Kyle Mouratidis over 10 years ago in reply to Steve Kipisz

Prodigy 150 points

Thanks for your help!

Kyle

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AM3703 SYS_BOOT pins