Embedian, Inc.
153
SMARC-iMX8M Computer on Module User’s Manual v.1.0
module through IO lines and disturbs the
SMARC
module power on
sequence. More seriously, it might cause to the CPU won’t boot up. It is
always recommended that the power on module has to be earlier than that
on carrier board.
The boot up of module depends on when you release the reset signal of
your carrier board. The module will boot up when the reset signal on your
carrier board is released. Before that, the module will not boot up. That’s
why designer needs to put the
RESET_IN#
in the last stage of power to serve
as the "
power good
" signal of the carrier board.
The module will not boot up till the module power is ready because the
carrier board hasn't released the reset signal yet.
The sequence is as follows:
Module Power Ready ‐‐>
CARRIER_POWER_ON
‐‐>
RESET_IN#
‐‐>Boot Up
4.1.5. RESET_IN#
The
SMARC
module does not know the IO power status from the carrier
board, and put
RESET_IN#
in the last stage of power can serve as the “
power
good
” signal of carrier board. This also assures that the power of carrier
board is good when
SMARC
module booting up.
4.1.6. VDD_IO
SMARC
1.0 specification defines the I/O voltage to be 1.8V or 3.3V or both.
The 3.3V
VDD_IO
is depreciated from
SMARC
1.1 specification.
SMARC‐iMX8M
supports 1.8V
VDD_IO
only.
4.1.7. Power Bad Indication (VIN_PWR_BAD#)
Power bad indication is from carrier board and is an input signal for Module.