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TM4C129CNCZAD: Crystal selection for custom TM4C129x board

Part Number: TM4C129CNCZAD
Other Parts Discussed in Thread: CC1310

We have a 24 MHz crystal that we use with the CC1310, and we would like to use it with the TM4C129x processor we have selected in order to keep our BOM easier to maintain.  After reading through the Clocks section of the datasheet (Section 29.9.5), I still have two main questions:

1. Will the Epson TSX-3225 24.0000MF15X-AC6 (with a load capacitance of 9pF) work for this chip if I use 10pF load capacitors?

2. Will using a 24 MHz crystal cause any weird clock issues with the UART, CAN, or USB peripherals using MOSC as their clock source?

I will admit, this is my first custom board design with the Tiva series chips, and I am transitioning from a different architecture to the Texas Instruments ARM architecture.  However, I did use the math laid out in Section 29.9.5 before posting here.

Thanks in advance.

  • Hi,

    The datasheet mentioned how the load capacitors (C1 and C2) to be chosen. If they meet the crystal manufacturer's requirement (you mentioned 9pF) then I think it is fine. You can also reference the table 24 where some part numbers of crystals that have been simulated and confirmed to operate.

    Are you using the Ethernet function? The Ethernet will require 25MHz OSC. The 24MHz will not work. Otherwise, I don't see an issue with UART, CAN or USB.
  • I am not using the Ethernet function.  In fact, the TM4C129C doesn't even have Ethernet built in.  Thanks for your quick response, I'm glad to hear that UART, CAN, and USB won't be affected.