For instance the pin:
MX6UL_PAD_GPIO1_IO05__USDHC1_VSELECT
If one is using GPIO_IO05 as the VSelect pin, what voltage is it using?
For instance in the description of IOMUXC_SW_PAD_CTL_PAD_GPIO1_IO05, it gives differing R0 values depending on voltage, but does not mention which pin is the source of the voltage. Does the voltage source depend on whether the pin is used as a GPIO, or a VSELECT on an SD card?
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Here is my experience.
The power main of i.MX6ULL can be found in i.MX6ULL datasheet.
For example:
NXP Semiconductors
Data Sheet: Technical Data
Document Number: IMX6ULLIEC
Rev. 1.2, 11/2017
You question about the pad/pin GPIO_IO05 power domain can be found following the NVCC_GPIO.
I usually use pins tool/ config tool to help me.
The tool can show lots of information, you do not have to search the document.
pins tool/config tool
suggest you give the real power voltage like below. If has power domain conflict, the tool will give you warning.
Here is my experience.
The power main of i.MX6ULL can be found in i.MX6ULL datasheet.
For example:
NXP Semiconductors
Data Sheet: Technical Data
Document Number: IMX6ULLIEC
Rev. 1.2, 11/2017
You question about the pad/pin GPIO_IO05 power domain can be found following the NVCC_GPIO.
I usually use pins tool/ config tool to help me.
The tool can show lots of information, you do not have to search the document.
pins tool/config tool
suggest you give the real power voltage like below. If has power domain conflict, the tool will give you warning.
Yes.
You still can use pads/pins for one here is usdhc1 in different power domain.
You need to write download dts like following.
pinctrl-0 = <&pinctrl_data &pinctrl_vselect>;
There is an example for using pins in difference power domain.
All those depend on the hardware design.
Sometimes you are free to select alternate pins.
However, the pin chosen determines the power domain. Changing the purpose of the pin through the mux cannot change the domain is my understanding.
In the case of VSELECT, it must be known to the hardware and cannot be any GPIO. For USDHC1, VSELECT is one of only three pins:
GPIO1_IO5: NVCC_GPIO
ENET1_RX_EN: NVCC_ENET
CSI_DATA07: NVCC_CSI
For USDHC2, VSELECT is one of only two pins:
ENET1_TX_DATA0: NVCC_ENET
GPIO1_IO08: NVCC_GPIO
Yes, it is.
Just one little issue on your reply.
You have two USDHC1-s.
My question still remains. What is the output voltage of pad GPIO1_IO05?
Does it depend on the mux setting? For instance, if it is set in the mux to USDHC1_VSELECT, is the output voltage of the pad determined by the voltage of NVCC_SD1? In general, how do I know for a give pad what its voltage will be? Is it influenced by the MUX setting of the pin or not?
Or is a give pad not influenced by the mux setting, and the same pad is always assigned to the same power domain.
Hi @JohnKlug,
Sorry, for the misunderstanding your reply helps me to clarify my answer.
In my example, if we use the pad as a GPIO1_IO05 the source will be NVCC_GPIO (3.3v for the EVK schematic), in the other case the source will be the source configured by the module. For your configuration as USDHC1_VSELECT the source will be NVCC_SD and based on our EVK this source could be 1.8v or 3.3v.
Best regards, Brian.
Is there any specific documentation that calls out each function pin individually and its power supply domain?
If you were to use SD1 for eMMC instead, would data pins 4-7 also be connected to NVCC_SD power domain? The documentation mentions data 0-3, but does not mention 4-7.
In the documentation it states that the I/O pins for the SDIO are controlled by NVCC_SD.
Normally I think off the I/O pins as being Clock, Command, and data, but you are saying that any pin tied to the SDIO interface is powered by NVCC_SD?
So the mux setting for the pad is important in determining which voltage is used by a particular pin of the CPU.
In the case of the MCIMX6ULL-EVK reference design, with SD1_VSELECT at 0V, the output of NVCC_SD will be 3V. With the output of SD1_VSELECT at high state, NVCC_SD will be 1.8V, so that means that SD1_VSELECT will swing from 0 to 1.8V.
Hi @JohnKlug,
Based on the Reference Manual for the iMX6ULL the VSELECT pin is an output signal used to change the voltage of the external power supplier.
Regarding, the voltage this pad is using, depends on your design and the device tree, for example in our EVK design for iMX6ULL have two sources that can be connected to this pad and is a designer decision.
As we can see in for NVCC_SD you can use 1.8v or 3.3v.
In addition to that, in the datasheet you can review the voltage ranges for both NVCC_GPIO and NVCC_SD.
About your second question the voltage source for this example will be NVCC_SD1 and you can decide whether use 1.8v or 3.3v.
I hope this information will be helpful.
Have a great day!
The NVCC_SD should be the usdhc data IO pins. Not for VSELECT pin.
The VSELECT pin be configured by
CSI_DATA07, ENET_RX_EN, GPIO1_IO05
and its power domains are NVCC_CSI, NVCC_ENET and NVCC_GPIO
Because I want put all of those pads/pins information together , so the pins tool/config tool found conflict and give strong red error.