topic Re: Schematic & Reference manual mismatch in Layerscape

Schematic & Reference manual mismatch

TrinathK — Tue, 02 Nov 2021 12:44:29 GMT

Hi all,

In LS1046A reference manual, it is mentioned that, QSPI_A_DATA[3] pin should be pulled low when IFC_GRP_A_EXT is selected as 001 (i.e., when pin is used as QSPI_A_DATA[3]). But in the schematics provided, it is not pulled low. Please check and confirm if pull down is required or not.

Attached images (text is highlighted) for your reference.

Thanks in advance.

Re: Schematic & Reference manual mismatch

r8070z — Wed, 03 Nov 2021 09:36:03 GMT

“001 {QSPI_A_DATA[3], Reserved, Reserved} NOTE: Must be pulled low when IFC_GRP_A_EXT is selected as 001“ means that when IFC_GRP_A_EXT is selected as 001 there are 2 reserved pins which must be pulled low.

Attached schematics looks like LS1046ARDB which was designed using preliminary documentation Due to that it shows these 2 pins as QSPI_A_DQS and QSPI_B_DQS. We should follow to the manual recommendation.

Re: Schematic & Reference manual mismatch

TrinathK — Wed, 03 Nov 2021 11:18:58 GMT

Hi Serguei,

Thanks for the reply.

So you are saying, pull down is applicable only for reserved pins and not for QSPI_A_DATA[3]. But the NOTE mentioned in the reference manual, looks like it is applicable for all the pins mentioned (i.e., QSPI_A_DATA[3], Reserved, Reserved). Please confirm if pull down is required for QSPI_A_DATA[3] or not.

Thanks in advance.

Re: Schematic & Reference manual mismatch

r8070z — Fri, 05 Nov 2021 07:30:58 GMT

Please see also Table 25. QSPI pin termination checklist in the QorIQ LS1046A Design Checklist , Rev. 2, 06/2020. Pull down for QSPI_A_DATA[3] is not required.