Archive for September, 2013

DDR Settings in Sabre Lite for i.MX6

September 16th, 2013

We were examining the memory configuration of the freescale i,MX6 Sabre lite board and found that some values of the configuration makes it work and other don't.

The main difference was due to locations 0x80c and 0x810 of the MXC_DCD_ITEM in the file board/freescale/mx6q_sabrelite_flash_header.S . The value that makes it work is

0x80c 0x001F001F
0x810 0x001F001F

And this one makes the board fail to boot.

0x80c 0x00440044
0x810 0x00440044

We figured out that the follwing lines ( at around line number 300) may make the optimal values for this board.

#MXC_DCD_ITEM(40, MMDC_P0_BASE_ADDR + 0x80c, 0x001F001F)
#MXC_DCD_ITEM(41, MMDC_P0_BASE_ADDR + 0x810, 0x001F001F)
#MXC_DCD_ITEM(42, MMDC_P1_BASE_ADDR + 0x80c, 0x001F001F)
#MXC_DCD_ITEM(43, MMDC_P1_BASE_ADDR + 0x810, 0x001F001F)

#MXC_DCD_ITEM(42, MMDC_P1_BASE_ADDR + 0x80c, 0x00440044)
#MXC_DCD_ITEM(43, MMDC_P1_BASE_ADDR + 0x810, 0x00440044)

MXC_DCD_ITEM(40, MMDC_P0_BASE_ADDR + 0x80c, 0x0023001B)
MXC_DCD_ITEM(41, MMDC_P0_BASE_ADDR + 0x810, 0x001F0025)
MXC_DCD_ITEM(42, MMDC_P1_BASE_ADDR + 0x80c, 0x0026001E)
MXC_DCD_ITEM(43, MMDC_P1_BASE_ADDR + 0x810, 0x00200027)

Most optimal values after taking into account trace delay of individual Byte lanes

We also notice the differences in the location 0x818 ( observed value 0x00022227). This difference is in Sabrelite and SabreSD. We will investigate and report more later.


Booting i.MX6 directly from SD Card

September 16th, 2013

The Sabrelite board from Boundary Devices come with the capability to boot from the NOR Flash. But the Freescale's i.MX6 has the capability to boot directly from the SD Card. Please note that this required changes in the hardware design.

In this post we will show yo how to burn your SD Card card to make uboot boot from the SD Card.

Run the following commands to install U-Boot.

dd if=u-boot.bin of=u-boot-no-padding.bin bs=1024 skip=1
dd if=u-boot-no-padding.bin of=/dev/sdx bs=1K seek=1

Make sure you replace /dev/sdx with the correct path for your SD Card. In my case it is /dev/sdb and the commands look like

dd if=u-boot.bin of=u-boot-no-padding.bin bs=1024 skip=1
dd if=u-boot-no-padding.bin of=/dev/sdb bs=1K seek=1

To be more precise I had to use sudo

dd if=u-boot.bin of=u-boot-no-padding.bin bs=1024 skip=1
sudo dd if=u-boot-no-padding.bin of=/dev/sdb bs=1K seek=1


SnapEDA - to provide open source hardware resources ?

September 15th, 2013

The problem with starting a new hardware design is the lack of resources - unlike the software where a huge number of open source software exist to jumpstart your software biz.  SnapEDA    attempts to change it by trying to provide all resources including open platform with support for footprints, schematics and a conglomeration of designers who can collaborate to bring out a new hardware design.

Natasha Baker, the brain behind SnapEDA, has an impressive background, having worked at Analog Devices and National Instruments. Her experience at Thomson Reuters gets her marketing advantage, otherwise not available to a mainstream star tup aspirants. No wonder, even when her website it in beta stage, she found mention in the techcrunch.

Baker was present at Disrupt’s Startup Alley this year, where she demonstrated her platform. Natassha says that SnapEDA is essentially a Github for hardware.  The community based around sharing CAD design for components footprint and symbols in circuit boards and electronics, including tools that allow schematics to be downloaded in a variety of formats compatible with all leading CAD programs, including, for example Allegro, Altium, PADS Power PCB, Cadstar and others.   A community validation tools  allow users to point out the problems with schematics or the footprint or to verify that they work correctly.

Besides the Schematics Symbols and Footprints SnapEDA also show data sheet, specs and the pricing and parts availability. Do you remember findchips

SnapEDA  plans to offer  CAD files that are convertible to every format - something that has not been done earlier.

There are reasons why SnapEDA may take off. But it needs to focus on reliable availability of the parts database. It will have to spend its own time to provide a good amount of database before the crowd sourced design files start to take off.