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.
69
3.3.24
I2C EEPROM Socket
According to SMARC
®
Rel. 2.1.1 specification, SMARC
®
modules have a dedicated I2C bus
(I2C_PM) from card edge connector dedicated to power management functions, such as Smart
Battery System Management. On the SM-B79 carrier board, this I2C bus is voltage level translated
from SMARC
®
modules before being used by these slave devices.
In addition, on SM-B79 carrier board, the I2C_PM bus is directly carried, at 1.8V electrical level, to
an 8-pin Flash Socket, type LOTES p/n ASPI0001-P001A, for the mounting of I2C EEPROMs in
SO-8 format, with the pinout on left table.
Signal description:
I2C_PM_DAT: SMARC
®
module Power management I2C bus DATA
I2C_PM_CK: SMARC
®
module Power management I2C bus CLK
There is a dedicated 2-way jumper, JP14, for driving signal I2C_Write Protect, allowing protecting this Flash EEPROM from writings.
3.3.25
JTAG Connector
On SM-B79 carrier board, for Debug Purposes, it is also available a MOLEX
p/n 70246-2004 or equivalent connector, with the pinout shown in the left
table. Mapping to SMARC
®
module card edge connector pins is also
provided within brackets.
Mating connector: MOLEX p/n 22-25-2202 with 70058 series female
crimp terminals.
For signal description, do refer directly to SMARC
®
module user manual intended to be used with
SM-B79 carrier board.
JTAG_TDI and JTAG_TDO signals share the same pins on the card edge connector with MDIO
signals used to manage the PHYs for SERDES interfaces. They are available on this connector only
in case they are supported by the SMARC
®
module; in this case, to use them as a JTAG, set
SW17 switch 1-3 in OFF position (par.3.3.15).
JTAG_TMS signal shares the same pin on the card edge connector with PCIE_B_CLKREQ# signal
request for M.2 WLAN Key E Slot, while JTAG_TCK shares the same pin on the card edge
connector with PCIE_A_CLKREQ# They are available on this connector only in case they are
supported by the SMARC
®
module; in this case, to use them as a JTAG, set SW14 switch 2-4 in
ON position and / or 3-way jumper CN78 in 2-3 position.
I2C EEPROM Flash Socket CN71
Pin Signal
Pin
Signal
1
-up 1.8V_DSW
8
1.8V_DSW
2
-up 1.8V_DSW
7
I2C_Write Protect
3
pull-up 1.8V_DSW
6
I2C_PM_CK
4
GND
5
I2C_PM_DAT
JP14
I2C_Write Protect
Not Inserted
Writings allowed
Inserted
Writings not allowed
JTAG Connector CN70
Pin Signal
Pin
Signal
1
+3.3V_ALW
2
---
3
JTAG_TRST# (P73)
4
GND
5
JTAG_TDI (S45)
6
GND
7
JTAG_TMS (P77)
8
GND
9
JTAG_TCK (P78)
10
GND
11
10k pull-down to GND
12
GND
13
JTAG_TDO (S46)
14
GND
15
JTAG_RST# (P72)
16
GND
17
---
18
GND
19
---
20
GND