
Table 1. Connectors, LEDs, buttons and headers (continued)
Circuit ref (Rev E)
Description
Default
Reference
SPI and I
2
C ports of the i.MX RT685
that are also designated for ISP
boot. This connector can be used to
work with a remote host, or as an
interface to off-the-shelf PMod
expansion boards.
J47
Flexcomm interface.
N/A
P1
Electret mic.
N/A
Schematic
SW1, SW2
User buttons. These buttons, when
pressed, pulls the connected i.MX
RT685 pin (
P1_1
for SW1 and
P0_10
for SW2) to ground. A 100 K ohm
pull up to
VDDIO_1
is connected to
the pin.
N/A
SW3
Reset button. When pressed, reset
is applied to the i.MX RT685,
TFA9894 amplifiers, Octal SPI flash,
pSRAM, expansion connector
(Arduino reset, if JP14 is installed).
N/A
SW4
PMIC on button.
N/A
SW5
Boot Config switch. ISP boot mode
selection. Switch the DIP switch for
ISP port signal to ON to pull that pin
low via a 1K ohm resistor. Switch 1
is for ISP0, 2 for ISP1 and 3 for
ISP2.
ISP0 ON
ISP1 OFF
ISP2 ON
U1
LPC4322.
N/A
Schematic
U6
Accelerometer FXOS8700CQ.
N/A
U8
Audio CODEC.
N/A
U12, U17
Digital Audio Amplifiers
N/A
U18
MIMXRT685.
N/A
Schematic
U19
Octal SPI Flash.
N/A
Schematic
U20
PMIC. Programmable output voltage
regulator with four different outputs:
SW1, SW2, LDO1 and LDO2.
N/A
U40, U41
On-Board DMICs.
N/A
U108
pSRAM
N/A
Schematic
shows location of jumpers and headers.
NXP Semiconductors
Board layout and settings
i.MX RT685 Evaluation Board, Rev. 0, March 20 2020
User's Guide
7 / 31