Clarification needed for MK70 DDR control register 21 specification Hello all, I am running into an issue with a MK70FX512VMJ12 controlling the DDR on a legacy board. We are using MQX. The issue comes from the following line in the bootloader: ddr->CR21 = 0x00060232; I assume that line sets the DDR_CR21 register (as described on the section 34.4.22 of the K70 reference manual) to 0x00060236. The reference manual states that the register field is split into 2 fields. 31–16 MR1DAT0 Data to program into memory mode register 1 for chip select .
15–0 MR0DAT0 Data to program into memory mode register 0 for chip select . Most DDR manufacturers call those registers Mode Register (MR or MRS) and Extended Mode Register (EMR1, EMR2, EMR3). Should I assume that data from field 15-0 will be written by the state machine to the DDR's MR (Mode Register) and data from field 31-16 to EMR? I suspect, and need confirmation from support engineers, that the state machine issues the necessary control signals irrespective of the values set in the DDR_CR21. That is because considering the data I write on bits 31-16 of the DDR_CR21 (0x0006) which assigns 000 to the 3 MSB bits, for proper operation those should be set to 001 as required by DDR specifications. Note from DDR specs: "The extended mode register is written by asserting LOW on CS#, RAS#, CAS#, WE#, BA1 and HIGH on BA0, while controlling the states of address pins A0 ~ A12." The settings needed for BA2, BA1, and BA0 are '001', while the values I write to DDR_CR21 is '000'. Does the DDR SDRAM controller overwrites those values set in DDR_CR21 to the correct ones? Thank you, dodocolby Re: Clarification needed for MK70 DDR control register 21 specification Hello @dodocolby ,
Thanks for using our community. I have noticed your question. I need some time to research before getting back to you. If there are any updates during this period, please feel free to share them anytime.
BR
Celeste Re: Clarification needed for MK70 DDR control register 21 specification Hello @dodocolby ,
Could you please let me know the mask set of your chip?
As far as I know, mask set 3N96B part has Errata e10521.
Also, what version of MQX are you using? I understand that MQX 4.x has an issue concerning the SIM_MCR DDRDQSDIS reset state, this bit needs to be cleared.
Although MQX is no longer supported, I noticed that in previous cases they all used
ddr->CR21 = 0x00040232; instead of the value you mentioned: 0x00060232.
For example, K70 DDR2 read failure with increasing temperature - NXP Community
K70 DDR2 temperature affect read data - NXP Community
That’s why I’m asking the questions above.
BR
Celeste
Re: Clarification needed for MK70 DDR control register 21 specification Hello, I am using MQX 4.2 and 5N96B. We implemented "K70 DDR2 read failure with increasing temperature - NXP Community K70 DDR2 temperature affect read data - NXP Community", and it seems the device is not sensitive to temperature anymore. Thank you Re: Clarification needed for MK70 DDR control register 21 specification Hello @dodocolby ,
Yes, the reason I referenced those two links is because I noticed the code they mentioned uses ddr->CR21 = 0x00040232 instead of 60232 . I just wanted to confirm that point, as I don’t have access to the MQX code on my side, it’s no longer supported. In addition, I’ve already reached out to the internal team to help address your question further. I’ll let you know as soon as I hear back from them. Thanks for your understanding.
BR
Celeste Re: Clarification needed for MK70 DDR control register 21 specification Hello @dodocolby ,
Sorry for the long wait. I haven’t received any updates from our internal team yet, likely due to the Christmas holidays. Please note that our response time may be longer than usual because of the holiday periods across the EMEA and AMEC time zones. I will also be on leave starting tomorrow until January 5th. If this matter is urgent, you may consider creating a new case and mentioning this link. Other colleagues will be able to locate my internal contact through this case, and there’s a chance you might receive an update before January 5th. If it’s not urgent, I will continue to follow up once I return. We truly appreciate your understanding and patience. Have a pleasant day!
BR
Celeste Re: Clarification needed for MK70 DDR control register 21 specification Hello @dodocolby ,
Hope you are great. I am sorry for the late reply. Please see the reply from our internal team: "
Because the DDR controller can support many different memory sizes and configurations with different total numbers of address pins, the mode register data loaded into the MRnDATA fields should not include the bank address values. The controller will automatically drive the correct bank address value (along with the other control signals for the mode register write command). The register value only needs to include the address line portion. "
Hope it helps. Please let me know if you have other questions.
BR
Celeste Re: Clarification needed for MK70 DDR control register 21 specification Thank you for the confirmation.
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