Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [sdio]

Secure Digital Input Output extends the SD card specification to cover input/output functions.

29 questions
13
votes
2 answers

Difference between 1-bit, 4-bit and 8-bit SDIO

Please help me understand the significance of 8-bit SDIO over 1-bit and 4-bit SDIO. Let me know the pros and cons of each type. Wiki or SDIO specification document does not discuss this.
V V Rao
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8
votes
4 answers

Why application notes advise series resistance to be added on clock lines for high-speed interfaces, like SDIO, and not on data lines?

Many application notes (like this one) advise series resistance to be added on the clock line, close to the source. I do understand that this resistance is added there to match the source impedance to the characteristic impedance of the line…
Ivan Vlaykov
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5
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1 answer

What is the difference between 1-bit SDIO vs SPI?

What exactly is the between 1-bit SDIO vs SPI? Does one have advantages/disadvantages over the other?
hassan789
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4
votes
2 answers

Micro SD card operating voltage: 1.8 V specified?

All manufacturer SD cards work in 3.3V based on SD specification. In our recent design we have tested SD card connector power to 1.8V, I thought no SD card will boot but some of the SD card are boot some of them are not booting. Could you please…
ramesh6663
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3
votes
1 answer

STM32 SDMMC & SDIO - why max 1 SD card only?

I'm writing an SDMMC driver for my C++ RTOS for microcontrollers and there is one thing which really puzzles me, making it hard to decide about class hierarchy. In the Reference Manual for STM32F7 (but the same is true for other chips, both for…
Freddie Chopin
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2
votes
1 answer

Clock line of SDIO bus has worse rise/fall time than rest of bus

I have an ATWILC3000 wifi module connected to a Raspberry Pi Compute Module 3+ over 4-bit SDIO. It's throwing a lot of bus errors at higher frequencies (currently running at 1 MHz for stability when it should be closer to 50 MHz). In probing the…
Joe Baker
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2
votes
1 answer

STM32 SDIO works only while probing clock signal

I have a custom board with an STM32F407VGT6 and an SD card slot. I noticed that I can only access the SD card if I have a scope probe attached to the clock signal. Holding a scalpel blade between my fingers and touching the tip to the clock pad…
Crazor
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2
votes
1 answer

SD card suddenly stops responding to CMD0 (RESET/SPI)

A device I had been testing for over two months suddenly started giving FR_DISK_ERR (I'm using Elm Chan's FAT-FS) [Link]. When I tried debugging, the command (CMD0) which must be clocked in to set the SD card into SPI mode (as described in the SD…
clamentjohn
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2
votes
1 answer

Using ESP32 as a wifi/bluetooth modem?

I'm would like to make a connection between a ESP32 and a Allwinner A20 CPU in which the ESP32 would provide the Wifi/Bluetooth connectivity for the rest of the system. They both mention i2c, spi and SDIO in their datasheets. Which one of those…
TheMeaningfulEngineer
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2
votes
2 answers

Use SDIO pheripheral for quad SPI flash memory

I am currently doing a project using the STM32F103 micro-controller. The project requires external flash memory to store images and data for later showing on LCD. The problem I have is that I want to see if I can use the SDIO peripheral on the…
James Attard
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1
vote
0 answers

SD Card CLK stops working properly on STM32F4 with SDIO connections

I have an SD Card socket connected to STM32F4 with the connections as follows: The firmware uses the following codes to initialize the SDIO: /* SDIO init function */ static void MX_SDIO_SD_Init(void) { hsd.Instance = SDIO; …
Patratacus
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1
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0 answers

How do I communicate with the Wifi module on an stm32mp157f-dk2 board in bare metal?

I'm trying to establish communication with the WiFi module on an stm32mp157f-dk2 board. I must be doing something wrong because I always get a timeout from SDMMC2. I attempt to send 2 commands, the first is an SDIO reset and the second is taken from…
Hammdist
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1
vote
1 answer

Sequential writing from different hosts to one SD/SDIO

I was wondering if it is possible to access one SD card via two or more hosts via some sort of hub and write to it data sequentially (i.e host1 writes a bulk then hostN writes another bulk)
Ma250
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1
vote
2 answers

Purpose of resistors on SDIO lines and antenna matching circuit?

What is the purpose of R40....R45 and pull-up resistors R46....R50 on SDIO lines as shown below? Is it really necessary to have L51, C52 & C53 matching circuit for antenna?
Lalit
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1
vote
1 answer

Wi-fi chipset with SDIO interface in SPI bus mode

I want to connect a Wifi-chipset, which offers an SDIO interfaces to a microcontroller that only supports SPI. As far as I understand from the specifications, every SD card can be connected to a host microcontroller on its respective SPI ports and…
oh.dae.su
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