Hi TI
A customer is inquiring about the difference between Datasheet and EVM Schematic for VSS_RTC processing.
Can I understand that VSS on Datasheet and GND_OSC1 on EVM circuit diagram are the same? Or ask if EVM designed it without following the guide. I think GND_OSC1 is the nearest PCB digital ground VSS...
TI, please explain. ^^
Thanks
Regards,
Jack
Hello Jack,
Thank you for the query.
Can I understand that VSS on Datasheet and GND_OSC1 on EVM circuit diagram are the same? Or ask if EVM designed it without following the guide. I think GND_OSC1 is the nearest PCB digital ground VSS...
The grounds that you are referencing seems correct. VSS_OSC and VSS_RTC are required to be connected to system ground.
Please refer below section of the AM335x Schematic Checklist
2.5 Clocking
• If you do not need RTC-only mode and the RTC timer feature, you do not need to include a 32 KHz crystal. The 32 KHz reference can come from the high frequency clock. Leave the RTC_XTALIN/RTC_XTALOUT pins as NC.
• Per Advisory 1.0.30 in the device Silicon Errata, VSS_OSC and VSS_RTC should be connected to system ground.
• It is preferable to always have bias and dampening resistors that can help tune the crystal later. For more details, see the Clock Specifications section of the device-specific data sheet.
Please refer below BBB schematics for implementation
Whenever there is a discrepancy between the Datasheet and EVM, it is recommended to follow the datasheet.
Regards,
Sreenivasa
