iMX RT1062 OEM Developer’s Kit - User’s Guide
Page 32
Copyright 2019 © Embedded Artists AB
It is possible to disconnect the SD memory card connector, J15, from the SDIO bus by
removing isolation resistors R86-R91. This is typically not needed except when running the
M.2 interface at very high SDIO bus frequencies. R86-R91 are found on the bottom side
under the LCD. Due to their location they are not easy to remove.
4.15.1
SP14: M.2 Power Supply and Control
The M.2 connector is powered with the peripheral 3.3V supply (PERI_3V3) as default. There is an
option to have a more advanced powering scheme (can be controlled in runtime to be either 3.6V or
3.3V). This option is not mounted as default.
It is possible to measure the 3.3V supply current to the M.2 connector via a 100 milliohm series resistor
and J30. The green LED12 lights when the power supply to the M.2 connector is present.
A 1.8V supply voltage is also generated since the M.2 standard dictates that some signals have 1.8V
logic levels.
A 32.768kHz clock signal with 3.3V logic level is generated, also according to the M.2 standard.
There is also an I2C-GPIO expander to generate a number of control signals. The status of three of
these control signals are also shown via LED13, LED15 and LED16.
4.15.2
SP15: Level Translation for BT UART and Control Signals
This schematic page contains voltage level translators for control signals and the UART to and from
the M.2 module. The i.MX RT OEM board operates with 3.3V logic level on these signals and the M.2
interface specify these signals to have 1.8V logic level. Hence the need for voltage translators.
It is possible to remove all connections of the control and UART signals to/from the M.2 connector by
removing the default bridge jumpers in J33.
It is possible to connect an FTDI cable (part number: TTL-232R-3V3) to pin header J36 in order to
access the UART channel. This can be used when debugging the UART communication with the M.2
module.
4.15.3
SP16: Level Translation and Audio Signal Multiplexing
This schematic page also contains voltage level translators, now for the audio interface signals. There
is also a multiplexor for the audio interface signals, controlled by two control signals. The table below
lists the possible settings.
AUDIO_CODEC_MUX_CTRL1
AUDIO_CODEC_MUX_CTRL2
Usage
Low
Low
Note a valid setting. Shall not be
used.
Low
High
M.2 audio interface connected to
i.MX RT OEM board signals.
High
Low
M.2 audio interface connected to
audio codec.
High
High
i.MX RT OEM board signals
connected to audio codec.
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