54LM20A sQSPI behavior is different with 54L15

[Jayant Tang]

Hello DevZone,

I have wrote a standard Zephyr display driver for one customer, I used sQSPI and Zephyr MSPI API.

I finished the development, but the QSPI (1-1-4 mode) plot on 54LM20 is different from that on 54L15. The code is same.

display requirement:


nrf54L15 v1.0.0

nrf54lm20 v0.3.4:


You can see that when transmitting the cmd and address, the voltage of D1, D2, D3 is different.
I'm not sure which one is correct.

Here is my code: github.com/.../display_a6ng.c
My NCS version is v3.2.2

Best regards,
Jayant

[PaKa]

Did you test again with a new nRF54LM20 DK? 0.5.4 for instance?

[Kenneth]

As Pål writes, you need engineering B (v0.5.4 DK), ref:
"Added experimental support for nRF54LM20A Engineering B."
https://docs.nordicsemi.com/bundle/ncs-latest/page/nrf/releases_and_maturity/releases/release-notes-3.2.1.html#highlights 

Kenneth

[Kenneth]

Do let me know if you see any issues on the v0.5.4 DK with engineering B.

Kenneth

[Jayant Tang]

Hello,

I got the 54LM20DK v0.7.0, the result is same as 54LM20DK v0.3.4.

The NCS version is v3.2.4.

Now this doesn't affect the normal qspi communication. It is just different with 54l15.

I'm not sure if there is any specification about this. Just let you know.

[Kenneth]

Thank you for the update, I am in contact with the team now.

Kenneth

[Kenneth]

Hello again,

Can you confirm that you have bias-pull-ups enabled on the pins in question for the nRF54LM20A?

Ref for instance:

	sqspi_default: sqspi_default {
		group1 {
			psels = <NRF_PSEL(SDP_MSPI_SCK, 2, 1)>,
				<NRF_PSEL(SDP_MSPI_CS0, 2, 5)>,
				<NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
		};
		group2 {
			psels = <NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>,
				<NRF_PSEL(SDP_MSPI_DQ2, 2, 3)>,
				<NRF_PSEL(SDP_MSPI_DQ3, 2, 0)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
			bias-pull-up;
		};
	};

Kenneth

[Jayant Tang]

Both 54L15 and 54LM20 contains `bias-pull-up` in group2:

54L15:

&pinctrl {
	sqspi_default: sqspi_default {
		group1 {
			psels = <NRF_PSEL(SDP_MSPI_SCK, 2, 1)>,
				<NRF_PSEL(SDP_MSPI_CS0, 2, 5)>,
				<NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
		};
		group2 {
			psels = <NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>,
				<NRF_PSEL(SDP_MSPI_DQ2, 2, 3)>,
				<NRF_PSEL(SDP_MSPI_DQ3, 2, 0)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
			bias-pull-up;
		};
	};

	sqspi_sleep: sqspi_sleep {
		group1 {
			low-power-enable;
			psels = <NRF_PSEL(SDP_MSPI_SCK, 2, 1)>,
				<NRF_PSEL(SDP_MSPI_CS0, 2, 5)>,
				<NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>,
				<NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>,
				<NRF_PSEL(SDP_MSPI_DQ2, 2, 3)>,
				<NRF_PSEL(SDP_MSPI_DQ3, 2, 0)>;
		};
	};
};

54LM20:

&pinctrl {
	sqspi_default: sqspi_default {
		group1 {
			psels = <NRF_PSEL(SDP_MSPI_SCK, 2, 1)>,
				<NRF_PSEL(SDP_MSPI_CS0, 2, 5)>,
				<NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
		};
		group2 {
			psels = <NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>,
				<NRF_PSEL(SDP_MSPI_DQ2, 2, 3)>,
				<NRF_PSEL(SDP_MSPI_DQ3, 2, 0)>;
			nordic,drive-mode = <NRF_DRIVE_E0E1>;
			bias-pull-up;
		};
	};

	sqspi_sleep: sqspi_sleep {
		group1 {
			low-power-enable;
			psels = <NRF_PSEL(SDP_MSPI_SCK, 2, 1)>,
				<NRF_PSEL(SDP_MSPI_CS0, 2, 5)>,
				<NRF_PSEL(SDP_MSPI_DQ0, 2, 2)>,
				<NRF_PSEL(SDP_MSPI_DQ1, 2, 4)>,
				<NRF_PSEL(SDP_MSPI_DQ2, 2, 3)>,
				<NRF_PSEL(SDP_MSPI_DQ3, 2, 0)>;
		};
	};