SM-B79
SM-B79 User Manual - Rev. First Edition: 1.0 - Last Edition: 1.0 - Author: A.R - Reviewed by M.B. - Copyright © 2021 SECO S.p.A.
67
3.3.21
FAN Connector
On SM-B79 carrier board it is available a 3-pin connector, type MOLEX p/n 22-27-2031 or equivalent, for
the connection of tachometric FANs.
Mating connector: MOLEX 22-01-2035 receptacle with MOLEX 2759 or 4809 KK
®
crimp terminals.
FAN_POWER: FAN Power signal, PWM controlled for FAN speed by using GPIO5/PWM_OUT signal coming from
SMARC
®
module. Furthermore, the voltage level is selectable to be at 12V_RUN or 5V_RUN. Selection must be done
through a 3-way jumper, CN55.
FAN_TACHO_IN: FAN Tachometer Input signal for SMARC
®
module
3.3.22
SPI interface
According to SMARC
®
Rel. 2.1.1 specification, SMARC
®
modules foresee up two Serial
Peripheral Interfaces, coming out from SMARC
®
card edge connector, for the connection of
external SPI devices, included boot devices.
The first one is SPI0, while the second one, SPI1, does share the same pins with QSPI or eSPI
interface.
The SPI0 interface available on SMARC
®
card edge connector is available both on
a SPI Flash Socket CN43, type LOTES p/n ACA-SPI-004-K01 or equivalent, and
on a dual-row 8-pin SMT male pin-header CN91, p. 1.27mm, type TOWNES
P1035-2*04MGF-084-A or equivalent, with pinout shown in the table on the left.
Signal description:
SPI0_DIN: SMARC
®
module SPI0 Master input / Slave output, also referred to as MISO
SPI0_DOUT: SMARC
®
module SPI0 Master output / Slave input, also referred to as MOSI
SPI0_CK: SMARC
®
module SPI0 Clock
SPI0_CS0#: SMARC
®
module SPI0 Master Chip Select 0, active low output signal
SPI0_CS1#: SMARC
®
module SPI0 Master Chip Select 1, active low output signal
3-Wire FAN Connector CN56
Pin Signal
1
GND
2
FAN_POWER
3
FAN_TACHO_IN
CN55 position FAN_PWR Level
1-2
12V_RUN
2-3
5V_RUN
SPI Flash Socket CN43
Pin Signal
Pin Signal
1
SPI0_CS1#
8
1.8V_ALW
2
SPI0_DIN
7
10
-up 1.8V_ALW
3
10
-up 1.8V_ALW
6
SPI0_CK
4
GND
5
SPI0_DOUT
SPI header CN91
Pin Signal
Pin Signal
1
SPI0_CS0#
2
1.8V_ALW
3
SPI0_DIN
4
SPI0_CS0#
5
SPI0_WP#
6
SPI0_CK
7
GND
8
SPI0_DOUT