Seco Smarc CSM-B79 User Manual page 48

3.3.10 microSD Slot
microSD Card Slot CN77
Pin Signal
1 SDIO_D2
2 SDIO_D3
3 SDIO_CMD
4 SDIO_PWR
5 SDIO_CK
6 GND
7 SDIO_D0
8 SDIO_D1
CardDetect SDIO_CD#
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managed directly by the SMARC
For ESD protection, on all signal lines are placed clamping diodes for voltage transient suppression.
JP5 position SDIO Write Protect
Not inserted WP Enabled: microSD card cannot be written
Inserted WP Disabled: microSD card can be written
CSM-B79
CSM-B79 User Manual - Rev. First Edition: 1.0 - Last Edition: 1.1 - Author: A.R - Reviewed by S.R. - Copyright © 2021 SECO S.p.A.
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According to SMARC Rel. 2.1.1 specification, SMARC
and MultiMedia cards over the SMARC
Storage Device and/or Boot Device (if the SMARC
Please refer to the User Manual of the used SMARC
The connector is a microSD connector, push-push type, H=1.68 mm, type JST DM3AT-SF-PEJM5 or equivalent.
Signal Description:
SDIO_CD#: Card Detect Input, indicating when a SDIO/MMC card is present
SDIO_CK: SD Clock Line (output)
SDIO_CMD: Command/Response bidirectional line, used for card initialization and for
command transfers.
SDIO_D[0÷3]: SD Card data bus, SDIO_D0 signal is used for all communication mode, SDIO_D[1÷3] signals are
required for 4-bit communication mode
SDIO_PWR voltage is derived from +3.3V_ALW power rail. It can be switched on and off via SW (SDIO_PWR_EN signal,
module).
Since microSD cards do not support the Write Protect functionality, which is instead
supported by SMARC
jumper, JP5, which allows forcing Write Protect signal input SDIO_WP, directly managed
by the SMARC
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module can support signals for Secure Digital Input/Output
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SDIO interface, for the use of standard SD or MMC cards, to be used as Mass
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module used with CSM-B79 implements this functionality).
® module for information about Card types supported by the chipset.
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module, then on CSM-B79 carrier board it is available a 2-way
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module
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