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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Signal Description:
/SATA_TX-: Serial ATA Transmit differential pair.
/SATA_RX-: Serial ATA Receive differential pair.
For the connection of external Mass Storage Devices, there is a standard male S-ATA connector, CN34.
Since SMARC
®
modules can manage only one S-ATA interface, then only one of the two connectors
(the SATA 7p M connector CN34 and the SATA M.2 SSD slot CN35) can work at a time.
Switching between the two connectors is automatic, and it is managed by the signal
SATA_M2_SELECT# available on SATA M.2 Slot CN35 (pin 69).
When M.2 SSD is not plugged, the SATA interface is redirected by default to the 7p M connector CN34.
Vice versa, when M.2 SSD is plugged, the SATA interface is redirected by default to SATA M.2 SSD slot CN35.
When both an M.2 SSD and a SATA Drive are plugged, the SATA interface is switched toward the M.2 slot.
3.3.9
S-ATA Power Connector
A dedicated power connector, CN37, can be used to give supply to external Hard Disks (or Solid State
Disks) connected to the SATA male connector CN34.
The dedicated power connector is a 4-pin male connector, type MOLEX p/n 89400-0420 or equivalent,
with pinout shown in the table on the left.
Mating connector: MOLEX 87369-0400 crimp housing with MOLEX 51021 crimp terminals.
SATA 7p M Connector CN34
Pin Signal
1
GND
2
SATA_TX-
3
4
GND
5
6
SATA_RX-
7
GND
S-ATA Power Connector CN37
Pin Signal
1
+12V_RUN
2
GND
3
GND
4
+5V_RUN