i.MX ProcessorsのトピックRe: EPD PMIC not recognized

EPD PMIC not recognized

joelronning — Wed, 28 Sep 2016 23:20:17 GMT

I have a i,MX 6SoloLite Eval Kit. I am booting off the MX6SLKEVK-E-INK SD card to Android. I was not able to procure an IMXEBOOKDC3-3 Eval Kit for EINK as they are obsolete. I did obtain the schematic and I have routed and built my own evaluation board which has a connector for the 6" EPD that I have obtained directly through eInk. It is my understanding that my 6" EPD is compatible with the E060SCM drivers referenced in the Linux documentation. I am working two paths 1) Linux - which will be what our final product will run on and 2) the Android demo provided with the Eval Kit. I would like to get the Android demo to work as this a known working system as shipped from the factory. I have a Linux image burned that boots and runs, I am having some issues figuring out how to specify the environment for the EPD on Linux. I will come back to my Linux issues after I get the demo working under Android - or I am told that the Android demo can't be configured as I require.

The first issue at hand appears to be that I used the TI TPS65180 PMIC on my board as I discovered the Maxim 17135 is obsolete. I have verified my EPD adapter board's PMIC operation by pulling the PMIC enable signals to enabling the voltages independent of the i.MX6 evaluation board. The TI PMIC is functioning properly ad providing the correct voltages to the correct pins on the display connector. Unfortunately, I get an error message at the end of the Android boot that indicates a PMIC failure - it appears that the driver may be reading the device ID? The PMIC does not get enabled and I do not see any activity on the EPD clock signals. The PMIC voltages are also not active - I am assuming that the PMIC is not being enabled. It is difficult to measure the enables directly with the i.MX6 eval board piggy-backed onto my EPD adapter board.

Is there a way to get the driver to ignore the PMIC or a way to specify the TI ?

Is the Android version set up similarly to the Linux version? I have located where I need to use setenv to the E060 and I have located a file in the BSD EPD_E060SCM.fw and have copied this to this to the boot SD card. However, I am not sure where to copy this to. After copying it to the SD card, Linux still defaulted to the LCD display driver, i.e. it did not recognize the E060 configuration that I am trying to reach. And advice here would be useful - I have downloaded some of the BSD. This is quite confusing so I am positive that things will get more clear as I become more familiar with.

Thanks, in advance, Joel.

Re: EPD PMIC not recognized

igorpadykov — Sat, 01 Oct 2016 00:08:53 GMT

Hi Joel

for connection of new epd panels one can look at attached

Chapter 5 ltib Linux Manual and Chapter 10 latest version,

sect.10.3.4.2 Using a Custom Waveform File. I am not aware

of epd ti pmic driver for latest kernels , seems one will have to develop it.

Unfortunately all epd tools and additional documentation are under NDA, so

may be recommended to apply to Professional Services

www.nxp.com/prosupport

or elevate this with local fae.

Best regards
igor
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Re: EPD PMIC not recognized

joelronning — Sat, 01 Oct 2016 01:18:32 GMT

Hi igor,

Thanks for reading and advice. I am aware of the sections of documentation that you have pointed out and the fact that the EPD is "top secret". We even met with 7 or 8 people at eInk at their China facility and they couldn't share anything about the EPD they sold us :) One of my issues is I need to get up to speed on Linux, Yocto, everything necessary to modify what I need to make the PMIC work.

The issue is not with timing or the EPD. Our EPD is supported by existing timing files. Rather it is that I designed in a different PMIC than the default Maxim IC. We need to address the PMIC registration. Should be in the device tree - I have not been able to locate the device tree source, only binary. I am working on getting to the bottom of this. There is a function get_regulator that services the PMIC in the device driver. I am also working on getting a system such that I can modify and rebuild whatever is necessary. My PMIC has built-in sequencing and is connected to the same enable output pins on the eval board - if I can fool get_regulator to think it has the Maxium PMIC and move forward, I think everything will be good. There are also environment variables at the U-boot level that pass into the driver. They are documented as "just type this and the wizard will make it work - no clear documentation on the parameters. The documentation that comes with a Stones CD is more complete than the CD flyer included with the sololite eval board.

I located a thread on this support site from someone that wrote or modified the driver for the TI chip. I am not sure I have to go this route or if there is an available option in the driver that supports the TI PMIC.

Have a great weekend!