3.4.10 Secure Digital Multimedia Card
The SD (Secure Digital) Card is a non-volatile memory card format used as a mass storage memory in mobile devices.
The SAMA7G54-EK has one Secure Digital Multimedia Card (SDMMC) interface that supports the MultiMedia Card (e.MMC) specification V4.51, the SD Memory Card specification V3.0, and the SDIO V3.0 specification. It is compliant with the SD Host Controller Standard V3.0 specification.
A standard MMC/SD Card connector, connected to the SDMMC interface, is mounted on the top side of the board. The SDMMC0 communication is based on an 8-pin interface (clock, command, four data and power lines). It includes a card detection switch.
The table below describes the pin assignment of SD/MMC connector J4.
| Function | Pin | PIO | Signal Description |
|---|---|---|---|
| SD Card data line 3 | 1 | PC2 | SDMMC1_DAT3_PC2 |
| SD Card command line | 2 | PB29 | SDMMC1_CMD_PB29 |
| Ground | 3 | – | Ground |
| 3.3V SD Card supply | 4 | – | VDD_SDCARD (3.3V) |
| SD Card clock line | 5 | PB30 | SDMMC1_CK_PB30 |
| Ground | 6 | – | Ground |
| SD Card data line 0 | 7 | PB31 | SDMMC1_DAT0_PB31 |
| SD Card data line 1 | 8 | PC0 | SDMMC1_DAT1_PC0 |
| SD Card data line 1 | 9 | PC1 | SDMMC1_DAT2_PC1 |
| SD Card card detect | 10 | PC4 | SDMMC1_CD_PC4 |
| SD Card write protect | 11 | PC3 | SDMMC1_WP_PC3 |
| Ground | 12 | – | Ground |
SDMMC data and control lines can be 3.3V or 1.8V, depending on the SD Card speed. A power voltage selector is implemented and controlled by pin PC5 of the MPU. The voltage selected by default is 3.3V.
The user can perform a hard reset of the SD Card by forcing the PB28 PIO of the SAMA7G5 device or by using the processor reset line (R262 must be populated) "NRST_OUT" signal.
This action disables the MIC94085YFT power switch and VDD_SDCARD is forced to ground. For more details about the MIC94085YFT power switch, refer to the product web page.
The table below describes the pin assignment of the SD/MMC interface.
| PIO | Signal Name | Shared With | Signal Description |
|---|---|---|---|
| PB28 | SDMMC1_RSTN_PB28 | – | SD Card reset signal |
| PB29 | SDMMC1_CMD_PB29 | – | SD Card command line |
| PB30 | SDMMC1_CK_PB30 | – | SD Card clock signal |
| PB31 | SDMMC1_DAT0_PB31 | – | SD Card data line 0 |
| PC0 | SDMMC1_DAT1_PC0 | – | SD Card data line 1 |
| PC1 | SDMMC1_DAT2_PC1 | – | SD Card data line 2 |
| PC2 | SDMMC1_DAT3_PC2 | – | SD Card data line 3 |
| PC3 | SDMMC1_WP_PC3 | – | SD Card connector write protect signal |
| PC4 | SDMMC1_CD_PC4 | – | SD Card card detect |
| PC5 | SDMMC1_1V8SEL_PC5 | – | SD Card signal voltage selection |
| NRST_OUT | NRST_OUT | – | Microprocessor reset output |