Background : Some customer wants to know the DRAM's MR register value. But, For now, we do not have any documentation or binary to complete this. So, this article aim to show how to read this register.
Hardware environment : i.MX8ULP EVK board
Software environment : uboot-imx : lf_v2024.04
1. The related registers information are as following:
DENALI CTL 165 [READ MODEREG[24:8]]
Read the specified memory mode register from specified chip when start bit set. Bits (7:0) define the memory mode register and bits (15:8) define the chip select. Set bit (16) to 1 to trigger.
DENALI CTL 166 [PERIPHERAL MRR - DATA[31:0]]
Data and chip returned from memory mode register read requested by the READ MODEREG parameter. Bits (7:0) indicate the read data and bits (15:8) indicate the chip. READ-ONLY
2. Test result :
Type the below command:
mrr <chip_select MR_register>
Like the below picture, when type the mrr 0 c, it means the chip select is 1 and the MR register is MR12, then the value of MR12 register can be output , is 0x1c.
Note : When read the MR register, must make sure the register has read right. Because most of MR register only have write right. you can check about it on JDEC spec document.
If you want to get the test binary file, please contact to me, i will send it to you.
