Which pins to use for SD card acces? (SD/SPI vs HSPI/JTAG/SD vs VSPI/SPI-Mode)

novalight
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Re: Which pins to use for SD card acces? (SD/SPI vs HSPI/JTAG/SD vs VSPI/SPI-Mode)

Postby novalight » Thu Jan 05, 2017 2:39 pm

Since the schematics of devKitJ V2 have been released we were about to take this as a reference. These schematics rise two questions for me: (find schematic screenshots attached)
- R_IO13 seams to be fitted with a pullup (R156) and a pulldown (R50) at the same time that does not make any sense for me
- R_IO12 pullup (R157) is NC, is this related to the Flash Voltage issue? How does this affect SD-functionality, could we also use the ESP32 internal pullup here?

What are the experiences with devKitJ V2 so far? (Especially regarding SD and JTAG)

EDIT: Added Schematic screenshots:
jtag.PNG
jtag.PNG (70.41 KiB) Viewed 523 times
sd.PNG
sd.PNG (106.83 KiB) Viewed 523 times

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rudi ;-)
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Re: Which pins to use for SD card acces? (SD/SPI vs HSPI/JTAG/SD vs VSPI/SPI-Mode)

Postby rudi ;-) » Mon Jan 09, 2017 9:37 am

happy new year!

example: https://github.com/espressif/esp-idf/tr ... d#hardware
(This example doesn't utilize card detect (CD) and write protect (WP) signals from SD card slot.)

best wishes
rudi ;-)
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rudi ;-)
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Re: Which pins to use for SD card acces? (SD/SPI vs HSPI/JTAG/SD vs VSPI/SPI-Mode)

Postby rudi ;-) » Mon Jan 09, 2017 4:48 pm

a Note if you use wRover Kit for testing this example
( tested with 16 GB SDHC ( primary partion 128 MB for the first test )

best wishes
rudi ;-)
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novalight
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Re: Which pins to use for SD card acces? (SD/SPI vs HSPI/JTAG/SD vs VSPI/SPI-Mode)

Postby novalight » Mon Jan 09, 2017 5:49 pm

Great to hear its working for you Rudi!

Did you do anything about IO13 and IO12?
If you have not modified anything could you confirm that IO12 is floating (in terms of no pullup) or did enable software pullups here?
For IO13 could you confirm it's beeing pulled between GND and 3V3?

Also one note on the side: If we enable internal pullups/down in our software and a random Reset/Brownout/Watchdog-Reset etc. occurs: can this lead to dangerous behavior (e.g. booting in download mode, locking up because of wrong VDD_SDIO)? How could one handle this?

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