K2E temp sensor

Hello Brad,

I do not find description for Temperature Alert Configuration Register in any of the document. I will check with the factory team and update you.

I assume like Keystone 1 devices, there is no pinned out temperature sensor nor is the temperature available via internal registers in keystone 2 devices too. However i would confirm this with the team and update.

Regards,
Senthil

Hi Brad,

I'm pushing this issue with the bootrom team. This may be an error in the data manual but give me a day to get the correct information.

Bill

Updates on this?

Hi Brad,
In reviewing this issue with the bootrom team, we found that the table is completely wrong. It's actually the table for the KeyStone I devices. I'm working on an update to the table for KeyStone II devices which I should have in the next day.
Regards,
Bill

The main thing I'm trying to understand is whether we have anything that measures junction temperature inside the device. Ideally I could just get a temperature reading, though even if I need to set a comparator threshold that would still be useful.

Bill,

Is there an update with regard to this question? Do we have TMS devices now that have this sensor trimmed and enabled? Does it allow you to actually read a temperature value, or is it only a comparator? If it's a comparator, is the trip point programmable? Any documentation or details would be appreciated. Thanks!

Brad

Bill, Brad,

Do you know if there is any additional information available in regards to this question?

Thanks,

Nuri

All-

We're using Keystone I (C6678) not Keystone II, but I'm adding to this thread because it's the only e2e post I can find that makes specific mention of  the "Temperature Alert Configuration Register".

In the c6678 datasheet this register is shown in the DDR3 Configuration Table.  Is it possible to use this register ?  We suspect that two of our DDR3 devices are overheating because they are on the bottom side of our board, which is adjacent to another board in the chassis with a tall heat sink hot spot that happens to be immediately next to these devices.

Thanks.

-Jeff
Signalogic

Hi Jeff,
The temperature sensors were added to the KeyStone 2 devices and are not present in the C6678. The register you referenced is part of the DDR3 boot parameter table for the RomBootloader. This is a generic table with a number of entries that are not used by the C6678. I can't find any reference to the temperature alert configuration register in the DDR3 users guide.
Regards. Bill

Bill-

Ok thanks for this info.  Can you think of anything at all -- DDR3 command we might issue, infrequent re-calibration procedure, etc -- that we might do to get an indication that DDR3 mem is running too hot ?  Basically something that has changed over 10+ hours of run time.

Thanks.

-Jeff
Signalogic

Jeff,

I can't think of any commands that would tell you whether the DDR is running hot. You could put a thermocouple on the part and capture the temperature across time.

Most DDR memory do require a higher refresh rate at higher temperatures. Since changing the refresh rate requires reconfiguration of the DDR, most of our customers who know they will be working in a higher temperature will use the higher refresh rate during their initial configuration. How are you handling that?

Regards,

Bill

Bill-

Thanks for your fast reply.  Ok on the DDR3 commands.

Yes we are going to try the 2x refresh rate, and we're working closely with Advantech on this (it's an 8901 board).  Is there any performance drawback to this ?

-Jeff
Signalogic

Hi Jeff,
It will eat into your throughput. I don't know what the percentage is but your DDR vender may be able to tell you that.
Regards,
Bill

We doubled the refresh rate at another customer last year. If I recall correctly, it was about a 5% degradation to the max throughput. Nothing too major. Should be an easy one to test!

Hello Bill,

I will access the temperature sensor on K2E too.

I have read the Document http://www.ti.com/lit/an/sprabx9c/sprabx9c.pdf

I can access the smart-reflex registers (0x02330000-0x02333FFF) on u-boot with the memory tools (md mw).
When linux is loading I can't access the smart reflex registers.
When I write to this registers I get always zero back.

The power domain is on:
devmem2 0x02350A34
Read at address 0x02350A34 (0xb6f13a34): 0x00001103

The pass pll is on:
devmem2 0x0262035C
Read at address 0x02350A34 (0xb6f13a34): 0x00001103

What is wrong?
How can I access the smart reflex registers from linux?

Hi Sebastian,

Just to clarify, you can access the registers using the memory tools or a JTAG connection but you are having trouble accessing the registers using linux, is that correct?

Regards,

Bill

yes, I can't access the register from linux.

Sebastian,

Please check MPU11 settings and check to see if access to that region has been enabled in the MPUs. If you have emulator, you can also use the GEL attached to see if you can read the registers through DSP or the DSP when Linux is booted up.

sensor.gel

Regards,
Rahul

Sebastian,

The possible explanation for not being able to access from Linux is because the same region was mapped already by kernel, and MMU requires the access to have the same mapping flag. Kernel may have it set as device, but devmem2 would be different.

I noticed that not only the SmartReflex0 is not accessible, but also the PSC at 0x02350000. The SmartReflex PID register read shows 0x00000000. That is different from what I get in u-boot. So I don't think Linux can access this area.

Rex

Hi Rex,

I have access  to the SmartReflex PID Register:

devmem2 0x2350000

Read at address  0x02350000 (0xb6f2e000): 0x44827200

u-boot output:

md 0x2350000 1
02350000: 44827200                               .r.D