Custom Allwinner V3s boards


#21

“Autorefresh” is used in normal mode. In low-power mode used “self refresh”.
It’s SDRAM feature, not V3s. However, need to patch kernel.


#22

I would suggest TI650231 as good PMIC candidate


#23

You talk about suspending to RAM, but my Linux uses nearly all of my RAM.
With Running SSH Server: 9Mb are left
without running SSH Server: 13Mb are left
How much RAM your Lichee PI needs?


#24

BGA packaged => ruled out


#25

Yes, but does the DDR2 SDRAM built into the V3s support autorefresh? And what support is required on the CPU for “suspend to RAM” mode: u-boot, kernel or both?


#26

With suspend to RAM, the CPU saves its own internal states (CPU, MMU and peripheral registers) to DDR SDRAM (which is not that big), put the DDR SDRAM into autorefresh mode (~20mA / package), then shuts down itself. It must then be awaken by an external source (like the AXP203 PMIC or external MCU), then either the u-boot bootloader and/or the kernel checks for resume information into DDR SDRAM, get back all registers if OK, then restarts where it left.

This is much faster than rebooting the Linux kernel from scratch.


#27

Hi @petit_miner - I’m investigating the possibility of a custom board as well. I’m looking at the voltage regulator options.

I’ll probably use a switcher for the 3.3v - but for the 3v / 1.2v / 1.8v I was thinking of using LDOs. Have you observed the current-consumption from the 3/1.2/1.8v busses - do you know if these are high current sections?

Also, did you have a chance to test the camera interface with a standard RPi camera? I like how you’ve designed it for compatibility with RPi.

thanks!


#28

Seems like 1.2v is for the CPU, and 1.8 is for the DRAM - these could pull a reasonable amount of current, I imagine.

Thinking of the PAM2306 for these sections, a LDO for 3.0v, and a bigger switcher for 3.3v.

However, if I can fit my 3.3v bus within 1A, I could just use two PAM2306’s for all voltages.


#29

Hey guys, where do you buy AllWinner V3s processor? I was looking at DigiKey, Mouser, Farnell and couldn’t find it anywhere.


#30

You will have to buy them at Aliexpress.
You can’t get them anywhere else.


#31

My final V3S Allwinner Board
all things is ok just resolution must modify for my custom board


#32

Wonderful work,

Is it possible to buy one ?
It could be empty board, not assembled, but assembled is preferable.

Mostly interested in MIPI camera testing and looks like you have connection for it .


#33

yes i tested Lcd and touch screen for this board
i add one I2C to GPIO expanded chip for increase number of GPIOs
I just have one problem with this board and direction of axis X+ and X- in lcd module is reverse and i canot modify touch screen module in image
this spec of board:
1-support lcd 40 and 50 pin standard with resistive and capacitive touch socket (12 and 6 pin standard)
2-support camera interface with raspberry pi pin2pin compatibility
3-audio and mic and speaker out interface
4-spi NAND and NOR flash
5-usb OTG and SD Crad and Ethernet 10/100 interface
6- 4 key user and LED user interface
7- header for SDIO wifi
8- powered from MICRO usb OTG +5


#34

look over here for your touch input problem:

simply edit the devicetree and recompile it and you are done :wink:

Where do you buy your displays?


#35

Nice boards you have designed. :slight_smile:

We are working on a V3s design, but the V3s datasheet doesn’t give an example for the Ethernet PHY connections. I would really appreciate it if someone could help me out here. I tried asking Allwinner, but I haven’t received any info from them (yet?). I also need value for the RTX resistor, in addition to the connections for the PHY (does it require termination resistors, does the transformer center pin need to be tied to +3.3 V etc.)

Thanks!


#36

Have a look at my schematics: I used the HR911105A Magjack.
I use a 6k resistor to ground for RTX (Pin 94).
Use many decoupling caps in different sizes 10µF 1µF and 100nF especially for the PHY. If your Ethernet link isn’t stable and shuts down randomly you have a problem with your decoupling caps.


#37

Thanks for the help. We can now finish our design. :slight_smile:


#38

One more question about the V3s: The datasheet mentions “BSP pin” which, when low, forces the CPU to boot from USB. We can’t find this pin - does it exist under a different name perhaps?

Just doing some final checks… :slight_smile: Thanks!


#39

I don’t know which pin that should be. You can have a look at the lichee pi zero Board and Base schematics which are available at Github.
The boot process is mentioned here.
So the V3s doesn’t need to be configured externally to determine the boot order.
EDIT: but there is a ID pin to determine if the V3s should work as USB host or USB device. This can be any GPIO. You can configure this in U-boot and the kernel.
EDIT2: Can you tell us what you are planning to do with the V3s? I’m very interested or is this “confidential”? :smile:


#40

We would seriously consider a custom V3s board for our application, but the critical thing is getting any kind of camera working on the CSI bus. I even have the suit with the camera module.

Any suggestions on getting this working? Does it require a binary device driver blob?