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.
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SPI0_WP#
1.8V_ALW. This means that when the external attached SPI device is powered, the protection from writing
is automatically removed.
1.8V_ALW signal. This means that when the external attached SPI device is powered, the Hold
condition of serial communication is automatically removed.
If SMARC
®
module selected to work with SM-B79 Carrier Board does not handle SPI0_CS1# signal, do not connect any SPI flash boot device in
CN43.
3.3.23
eSPI interface
According to SMARC
®
Rel. 2.1.1 specification, SMARC
®
modules second SPI (SPI1) can be implemented as QuadSPI (QSPI) or enhanced SPI (eSPI). In case
selected SMARC
®
module has the support for eSPI, this interface is available both on an eSPI Flash Socket CN69, type LOTES p/n ACA-SPI-004-K01 or equivalent,
and on an internal 14-pin dual row p.2.54 mm header CN44 (type MOLEX p/n 70246-1404 or equivalent), with the following pinout:
Signal description
ESPI_CK: SMARC
®
module eSPI Master Clock Output
ESPI_IO_[0:3]: SMARC
®
module eSPI Master Data Input / Outputs. These are bi-directional input/output signals used to transfer data between master and slaves.
ESPI_CS0#: SMARC
®
module eSPI Master Chip Select #0. Active low output signal.
ESPI_CS1#: SMARC
®
module eSPI Master Chip Select #1. Active low output signal.
ESPI_RESET#: SMARC
®
module eSPI Reset Signal for both master and slaves devices. Active low output signal.
ESPI_ALERT0#: SMARC
®
module eSPI signal used by eSPI slave to request service from the eSPI master. Active low input signal.
ESPI_ALERT1#: SMARC
®
module eSPI signal used by eSPI slave to request service from the eSPI master. Active low input signal.
eSPI Flash Socket CN69
Pin Signal
Pin Signal
1
ESPI_CS0#
8
1.8V_ALW
2
ESPI_IO1
7
---
3
ESPI_IO2
6
ESPI_CK
4
GND
5
ESPI_IO0
eSPI Header CN44
Pin Signal
Pin Signal
1
GND
2
ESPI_CS0#
3
ESPI_CK
4
ESPI_IO3
5
---
6
ESPI_IO2
7
ESPI_RESET#
8
ESPI_IO1
9
3.3V_RUN
10
ESPI_IO0
11
ESPI_ALERT1#
12
ESPI_CS1#
13
3.3V_ALW
14
ESPI_ALERT0#