OMAP3530 sys_nreswarm signal problem

ler

Other Parts Discussed in Thread: OMAP3530

Hello,

We are bringing up our first OMAP3530 board. Following the timing diagram on page 132 of the OMAP3530 data sheet (SPRS507B) all signals seem to be accounted for except

for sys_nreswarm. It remains low and does not rise following the positive going EFUSE signal. What could be causing this? I don't have any external memory hooked to the device (yet)

and am wondering if I should fix this problem before we move ahead? What is required for sys_nreswarm to go high?

Thanks.

over 17 years ago

0 BrandonAzbell over 17 years ago

TI__Guru 64980 points

Do you have an external pullup resistor connected to sys_nreswarm?

The OMAP3530 Technical Reference Manual (SPRUF98) indicates sys_nreswarm is an bi-directional, but open drain signal. This is indicated in Section 25.2.2.3.
Also, the OMAP3530 datasheet (SPRS507) indicates this in Table 2-1 on page 30.

0 ler over 17 years ago in reply to BrandonAzbell

Expert 1070 points

Brandon,

I have a 4.7K pull-up to 1.8V.

Loren

0 Bernie Thompson TI over 17 years ago

TI__Mastermind 41665 points

There are a couple of errata that you may want to consider depending on your silicon revision such as advisory 3.0.1.36 or 2.0.1.80 from the OMAP3530 Errata Document.

Aside from this, are the voltage rails and clocks within the datasheet specifications when the sys_nreswarm is stuck? Is sys_nreswarm always stuck or is it releasing sometimes?

0 ler over 17 years ago in reply to Bernie Thompson TI

Expert 1070 points

Bernie,

Thanks for the input. I found that the I had connected (on my board) the SYS_nRESPWRON signal to the TV_VREF line accidentally thus causing

the SYS_nRESPWRON signal to be in an indeterminant state. Anyway, looks like I'm pulling current on the processor now, so time to get the JTAG up

and running.

Thanks again.

Loren

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OMAP3530 sys_nreswarm signal problem