ESP32 4Bit SD-Mode Init problem

[stefan.erni]

Hi Ben

Here a program to test the SD-Card:
Press a key to start (GPIO19 on my board)
The program write 10'000 line in a .csv file
Its write a string of 128Byte for each line (21 times a fix number 10000,)
If writing is finish it's write the time in line 10'001 in mSec and it send the time to USB

2025-06-10_12-05-58.PNG (5 KiB) Viewed 25 times

Test_post_sd_0525.fcfx

(33.22 KiB) Downloaded 3 times

I tested with different setting for the card
the setting from the clock to 1Mhz, 20Mhz, 80Mhz is no difference
the setting 1Bit or 4Bit mode=> 1Bit=2935mSec 4Bit=2551mSec

My wish is that the writing of 128Byte always takes the same time or that there is not such a big difference to write the string

test shows the time to write for 128Byte, you van see every 4te string is much longer ( with a 1mSec delay on)
here the 4te string

2025-06-10_11-28-39.PNG (126.49 KiB) Viewed 25 times

and sometimes it's much longer...

2025-06-10_11-29-44.PNG (196.96 KiB) Viewed 25 times