Replace sd card by emmc

Hardware
1

Does anyone try to replace the sd card in pixhawk by emmc?

we had try to connect the CMD, CK, D0~D4 to emmc BGA pin, and also include VSS, VDDF, VDDI, but failed to startup.

Then we try a small pcb board convert emmc to sd, we connect the sd card to computer, copy file to sd, everything is ok, but when we connect CMD, CK, D0~D4 from pixhawk to sd, it failed again.

At last, we connect the pixhawk to tf card directly, it could startup, no problem.

So I suppose it maybe some wrong from emmc to SD, maybe something different in STM32 or the driver of APM, Does anyone have experience to do that?

2

I am sure that the Pixhawk ( STM32F427 )hardware supports MMC. The Pixhawk uses the PX4/Nuttx OS and drivers for SDIO so it is probably best to consult their documentation to see how to enable MMC.
It looks like there is a Nuttx/Px4 driver for it


So it is just a question of enabling it maybe?

3

I just suppose that the SD card and emmc is the same in driver, which both through the SDIO.
Is that mean some different between SD and emmc?

4

Since the format can be detected, it may be that, if the format is found to be MMC it is rejected

https://github.com/PX4/NuttX/blob/master/nuttx/drivers/mmcsd/mmcsd_internal.h#L67

That is a guess. It is probably best to ask on the PX4 forum and/ or raise an issue on Github/ArduPilot

5

Hello jin,
How to solve it ?
What kind of card you use?