Re: [Gumstix-users] Summit 1.8V current draw and rxd level

[Thierry G. <t.g...@gm...>]

Hi,

This is interesting. It looks like you are right about the VCC_1.8V
signals on the 40-pin and 60-pin connectors. The 1.8V is generated on
the expansion board, and does not come from the COM itself.

The following pages would need to be corrected then:
http://www.gumstix.net/Hardware/view/I/O-connectors-cabling/Gumstix-Overo-60-pin-header/112.html
http://www.gumstix.net/Hardware/view/I/O-connectors-cabling/Gumstix-Summit-board-40-pin-header-SV1/112.html

When is SYS_EN toggled? By the TPS65950 when its input is stable? By
uboot? Or is it as late as when linux boots?

Regards,

Thierry


On Mon, Feb 8, 2010 at 11:51 PM, R. P. McMurphy <log...@gm...> wrote:
> The 1.8V on the Summit board 40 pin connector does not come from the
> Overo PMIC. It comes from the MIC5247 mounted on the Summit board. The
> output is only enabled when SYSEN is output from the Overo module so
> the Overo must be up first before you get 1.8V.
>
> The Micrel webpage say it 150mA but some of that is used for the FTDI
> I/O and as a voltage reference for the video driver.
>
> http://www.micrel.com/page.do?page=product-info/products/mic5247.shtml
>
> On 2/9/10, Tyler Southard <sou...@gm...> wrote:
>>
>> Hi,
>>
>> I was trying to find the current rating for the VCC_1.8 pins on the Summit
>> board (pins 26 and 16) in the manual for the tps65950, but I couldn't find
>> it... Does anyone know how much current I can draw from those pins to power
>> other electronics?
>>
>> Also, the voltage level on the RxD1 pin (pin9) on the Summit reads around
>> 0-160mV, not 1.8V. Does anyone know why it would do this or what I can do
>> about it?
>>
>> Thanks,
>> Tyler
>> --
>> View this message in context:
>> http://old.nabble.com/Summit-1.8V-current-draw-and-rxd-level-tp27507073p27507073.html
>> Sent from the Gumstix mailing list archive at Nabble.com.
>>
>>
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