Sd Matrix - Sferalabs Iono Pi Max v2 3+ Lite User Manual

SD matrix

Iono Pi Max implements a flexible dual microSD card architecture.
Iono Pi Max routes its two microSD card holders to the Compute Module through a high-
speed switching matrix, controlled by the on-board microcontroller. Each SD card can be
set as the boot card, with the other available as additional storage.
This enables for separate OS/data storage, SD redundancy and in-field full-system
upgrades.
The BCM283x in the Raspberry Pi Compute Module supports two SD card interfaces, SD0
and SD1.
The first (SD0) is a proprietary Broadcom controller that does not support SDIO and is the
primary interface used to boot and talk to the eMMC or SDX signals. The CM will always
try to boot from this interface first.
The second interface (SD1) is standards compliant and can interface to SD, SDIO and
eMMC devices.
Both interfaces can support speeds up to 50MHz single ended (SD High Speed Mode),
and this speed is supported by the Iono Pi Max SD matrix as well.
Iono Pi Max has two microSD slots, called SDA (bottom) and SDB (top), and the SD matrix
allows 2x2 connections between both SDX/SD1 interfaces and the SDA/SDB slots.
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Pin # Description
1 5 VDC out
2 AUX in/out (active low)
3 SCL
4 SDA
5 GND
6 GND
EXP INTERFACE PLUG PINS
Iono Pi Max User Guide