3.9. SDIO Interfaces¶
|51, 95||SD1_CD SD2_CD||SD Card Detect – connected to a GPIO||VDDIO||I|
|52, 96||SD1_D SD2_D||SD Data bidirectional signals||VDDIO||I/O|
|53, 97||SD1_D SD2_D|
|54, 98||SD1_D SD2_D|
|55, 99||SD1_D SD2_D|
|56, 100||SD1_CMD SD2_CMD||SD Command bidirectional signal||VDDIO||I/O|
|57, 101||SD1_CLK SD2_CLK||SD Output Clock.||VDDIO||O|
|TX25, TX28, TX48||Only one SD-Card available on standard pinout, SD Interface 2 is not used / not connected.|
|TX28||Pin 101 is used as ENET_CLK.|
The TX pinout provides two dedicated SDIO interfaces. SDIO stands for Secure Digital Input Output which can also be used for SD-Memory-Cards.
3.9.1. SD-Card example diagram using level shifters¶
No external pullups are needed here. Each port of the TXS0108E has an internal pull-up resistor. These have a value of 40 kΩ when the output is driving low and a value of 4 k Ω when the output is driving high. Unfortunately the card detect feature commonly used for Micro-SD cards on DAT3/CD cannot be used. A dedicated card detect switch is required.
3.9.2. SD-Card example diagram only for 3.3V modules¶
Either the use of the processor internal pullups or the use of pullups on the baseboard is possible.