[Arm-netbook] Microdesktop v1.7

Pičugins Arsenijs crimier at yandex.ru
Tue Jul 17 14:02:01 BST 2018

Some thoughts:

> 3. Add another SY6280 current limiter for +5V and connect to VGA pin
> 9 (VESA power). Seems to be some difference of opinion on current
> requirements: 50mA[2], 300mA-1000mA[1]. If we were to limit at
> 300mA, it should easily supply the needs of I2C serial EEPROM and
> probably not over-tax our power supply.

I've also seen the VGA/HDMI +5V used to power various converters
(most often, HDMI->VGA, but I imagine the inverse is sometimes used 
as well).

> For VESA_SDA and VESA_SCL, add diode limiters connected to ground
> similar to ESD117-ESD123 on the SD bus lines provided the
> diode-limiting voltage is greater than VREFTTL nominal range.
> Otherwise use BAT54S connected between ground and VREFTTL.

Is it not possible that VESA_SDA and VESA_SCL are 5V? If so, they could
require level shifting from 5V, am I wrong here?


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