Our customer has question below.
Customer evaluating own board using CPU: i.MX6Quad, PMIC: MMPF0100F0ANESR2.
But when power supply problems occur that boot from the boot device (eMMC used) specified by the BOOT_CFG pin of the CPU .
By the way, it will start up by manually controlling the reset signal POR_B (H → L → H)is no problem, we believe there is no mistake in the setting of the BOOT_CFG pin itself.
For the cause investigation, the power supply start sequence of SABRE - SDB and customer board was compared.
As a problem, on the customer board, it turned out that POR_B output by PMIC was controlled to H (reset release) before VDDARM_CAP was output.
※ In the SABRE-SDB, this order is reverse.
This is contrary to the following description of the reference manual IMX6DQRM, P.5084, so I think that a problem has occurred.
60.5.1 External POR using SRC_POR_B
If the external SRC_POR_B signal is used to control the processor POR, SRC_POR_B must remain low (asserted) until the VDD_ARM_CAP and VDD_SOC_CAP supplies are stable.
1, Does SABRE - SDB use the default "F 0 "OTP setting?
Customer used F0 OTP settings.
2,Is SABRE-SDB doing OTP rewriting / customization from the default "F0"?
3,On the SABRE-SDB, when "F0" OTP is being rewritten, which address
What kind of values are rewriting?
4,When OTP is not rewritten, what will be assumed as the reason for the difference in the timing of the power supply
startup sequence between the SABRE-SDB and customer board?
5,I tried AN4546 (MMPF0100 OTP Programming Instructions) method to change the PMIC timing, but I could read
registers other than OTP, but I can not access the OTP region register.
Address 0x80 Is OTP FUSE READ EN required to write 0x01 before reading OTP?
6,When the output voltage of MCIMX 6Q-SDB was measured with an oscilloscope here
In the default sequence of PMIC F 0
9th VGEN 1
10th VGEN 2
11th VGEN 3
12 th VGEN 5,
In actual measurement
VGEN 1 and VGEN 2, VGEN 3 and VGEN 5 are running at the same timing, respectively.
Is it a custom OTP rather than the default sequence of F0?