Interfaces
13
LEC-BTS
3.9
I2C Bus
The LEC-BTS provides four interfaces through the I2C bus for General Purpose, Power Man-
agement, Camera, and LCD video I2C signals with operating speeds up to 400kHz. All I2C
interfaces have 1.8V pull ups with 2.2k resistors.
3.10 SPI
The CPU implements an SPI controller, which supports two SPI Flash devices on the module for
BIOS storage.
3.11 Serial (UART)
The LEC-BTS provides two serial interfaces: One port is a high-speed, 4-wire port (with TX/RX
and RTS#/CTS#), and one port is 2-wire (with TX/RX only.)
3.12 I2S
The SMARC connector provides three pins for an LPE_I2S audio interface. The LPE_I2S inter-
face is brought out through the I2S0 pins on the SMARC connector.
3.13 SD/SDIO Interface
Four parallel data lines comprise the SD/SDIO interface, supporting SD Card sockets.
3.14 eMMC Interface
The LEC-BTS provides one 8-bit eMMC interface port, brought out from the CPU through the
SDMMC pins on the SMARC connector.
3.15 GPIO
The LEC-BTS provides 12 GPIO signals from the CMOS device on the module. The GPIO sig-
nals can be utilized for General Purpose IOs as well as camera, HDA, PWM, TACH, and CAN
interfaces.
3.16 LPC Debug
A 40-pin, front flip, DB40 connector allows access to debug and update the BIOS, BMC, and OS
code on the module. (Refer to “Debug (DB40)” on page 22.)
Table 3-1: GPIO Default Settings
SMARC Connector Pin
Default Function
GPIO0
CAM0_PWR#
GPIO1
CAM1_PWR#
GPIO2
CAM0_RST#
GPIO3
CAM1_RST#
GPIO4
HDA_RST#
GPIO5
GPIO
GPIO6
GPIO
GPIO7
GPIO
GPIO8
GPIO
GPIO9
GPIO
GPIO10
GPIO
GPIO11
GPIO
