Full Size Sd Card Boot Options - Freescale Semiconductor i.MX53 Quick Start Manual

Hardware Reference Manual for i.MX53 Quick Start
5.7. Full Size SD Card Connector
The full size SD Card connector (J5) is directly connected to the eSDHC channel 3 module of the i.MX53
Applications processor. This card socket will support up to a full 8‐bit data transfer from an SD card,
SDIO device, or MMC card inserted into the socket. The Quick Start board was designed by default not
to boot from the J5 card socket. If the developer wishes to boot from J5, the following options shown in
Table 11 below are available:
Option
Boot From J5 Card Socket
High Speed Operations
Fast Boot
SD Card Operations
MMC Card Operations
The Quick Start board is configured to have the ROM code try to initiate boot operations in the 4‐bit
data mode, by setting BOOT_CFG[6:5] to (01). Section 6.4.3.6 explains the SD/MMC boot options in
greater detail for the interested developer.
Main power to the SD Card Connector is from the external LDO regulator (DCDC_3V2). If this regulator is
turned off for power savings purposes, the card socket will not function. It is possible for the developer
to cut the trace between the pads of SH32 and attach a different source of power to the pad next to the
card socket via a wire solder. Note that the eSDHC module internal to the i.MX53 processor is operating
at 3.3V, therefore it is recommended that the alternate source also be 3.3V. Cutting the SH32 trace
should only be used if a SDIO device inserted into the socket is drawing more power than the LDO
Regulator is capable of supplying.
The SD3 Clock trace has a 22 Ohm series termination resistor (R212). This resistor is inserted to prevent
a reflected signal from being sensed by the i.M53 processor. This has been found to occur on MMC card
operation and is recommended for all designs. In addition, the following eSDHC channel 3 traces are
pulled high to 3.2V (DCDC_3V2).
SD3 Command (R89)
SD3 Card Detect (R88)
SD3 Write Protect (R87)
Freescale Semiconductor
Hardware User Guide for i.MX53 Quick Start Board,
Net Condition
EIM_DA6 Pull High
EIM_A18 Pull High
EIM_A19 Pull High
EIM_A20 Default Low
EIM_A20 Pull High
Table 11. Full Size SD Card Boot Options
PUBI – Public Use Business Information
Notes:
Position 2 on DIP Switch SW1
Position 6 on DIP Switch SW1
Position 7 on DIP Switch SW1
Position 8 on DIP Switch SW1
Position 8 on DIP Switch SW1
Preliminary Rev 0.91
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