FNIRSI-1013D "100MHz" tablet oscilloscope

[sub77]

Hi

Thank you for your work and development of this project.
 Unfortunately, when I installing rtc, I broke the capacitor.
Please, if there is information about its characteristics (capacity) for its replacement, I will be grateful. Thanks in advance

[Russell2024UK]

Hi Sub77 oh wow its so easy to break small SMD items .. I have taken mine 1013D apart which i fitted the RTC - (Its all ways best to remove the item then measure with test equipment however to risky so did not this time  ) Removed one wire measured in circuit as per pictures .. Measured across the white capacitor Hope it helps 

[pcprogrammer]

Hi

Thank you for your work and development of this project.
 Unfortunately, when I installing rtc, I broke the capacitor.
Please, if there is information about its characteristics (capacity) for its replacement, I will be grateful. Thanks in advance

It might just work without the capacitor. Normally one would not even add a capacitor between I2C SCL and SDA, but they did it to overcome some problems they have with the bit banged I2C.

Try it without and if it works with the original firmware, don't bother putting another one in. If it does not try it with the 2.2nF Russell2024UK measured.

[Sleo]

Removed one wire measured in circuit as per pictures .. Measured across the white capacitor Hope it helps 

No, no, it's not correct to measure soldered capacitors. This capacitor is made of white ceramic NP0; its capacitance should be relatively small, no more than 1000 pF. To measure it, you need to unsolder it.
I did it, the capacitance is 20 pF, dielectric NP0, size 0603, voltage is not important (usually 50 V). Measured with Mastech MS5308.

[Sleo]

Has anyone used a 4GB card? I tried to check what types of file systems the oscilloscope works with, but the alternative firmware does not start at all with a 4GB card, no matter FAT16 or FAT32. FNIRSI firmware works fine with this card - saves pictures and waves. Perhaps the problem is in the speed of the card, it is quite old. The card has been checked for bad sectors etc., everything is fine.

[pcprogrammer]

Has anyone used a 4GB card? I tried to understand what types of file systems the oscilloscope works with, but the alternative firmware does not start at all with a 4GB card, no matter FAT16 or FAT32. FNIRSI firmware works fine with this card - saves pictures and waves. Perhaps the problem is in the speed of the card, it is quite old. The card has been checked for bad sectors etc., everything is fine.

The speed thing most likely is the issue here. I have tried it also with a 4GB card that I have. Works with a card reader on the PC, the original firmware but not with the new firmware. The same happens on the 1014D. See here https://www.eevblog.com/forum/projects/reverse-engineering-the-fnirsi-1014d/msg5508868/#msg5508868

A couple of days back I used that same SD card in a Milk-V Duo board and the startup took about two and a half minute. With another 32GB card it started in about 10 seconds.

The problem with the new firmware probably has to do with it not recognizing the speed information of the card properly. It just switches over to high speed mode and then the card fails. Have not looked into it any further.

Edit: The firmware only works with a FAT based file system. It is based on open source code found here http://elm-chan.org/fsw/ff/

[Sleo]

Edit: The firmware only works with a FAT based file system. It is based on open source code found here http://elm-chan.org/fsw/ff/

I know. Just trying to replicate Russell2024UK's situation with a card that my loader detects as FAT16-LBA.