TM4C1294NCPDT: Comparison to TM4C1292NCPDT

Joseph Hancock38

Part Number: TM4C1294NCPDT
Other Parts Discussed in Thread: TM4C1292NCPDT

Hi,

I have been using the TM4C1294NCPDT for a while and need to populate a new board. I've been unable to find stock anywhere of the component and so I'm looking for a substitute. It looks like the TM4C1292NCPDT is a practically identical part so I'm hoping to use it as a drop in replacement. My initial review is showing the only major differences occur in pins 51-59 and I have those connected up as directed in the TM4C1294NCPDT data sheet. However, I am not using any of those pins excluding the VDD and ground connections.

If anybody can provide some advice, I'd much appreciate it.

Thanks,

Joe

over 6 years ago

0 Joseph Hancock38 over 6 years ago

Intellectual 615 points

I neglected to mention in my original post that the boards have already been fabricated. Thanks!

0 Ralph Jacobi over 6 years ago in reply to Joseph Hancock38

TI__Guru*** 131520 points

Hello Joseph,

There is a storage of stock due to high demand for the devices. Depending on your time frame you may just be able to wait for it. Are you not using Ethernet on just that board but are on other boards using the same design? Just curious as to the reasoning for using the Ethernet enabled device when you seemingly don't need Ethernet.

As far as the two devices are concerned, the primary issue would be to properly handle the VDD pin that is now present, and correctly configuring the new GPIO's. Aside from that I don't see anything else that raises a concern.

0 Joseph Hancock38 over 6 years ago in reply to Ralph Jacobi

Intellectual 615 points

Hi Ralph,

Thank you for your response. The part selection was made to mirror the launchpad that we had on hand. Can you expand on the proper handling of the VDD pin? Will we need to cut the trace or can we simply reconfigure the pin to high-z with a pullup when we go to program?

Thanks,
Joe

0 Ralph Jacobi over 6 years ago in reply to Joseph Hancock38

TI__Guru*** 131520 points

Hi Joseph,

In general there should be filter caps on the VDD pins, so the ideal method if you only have a few boards to make would be to cut the trace and route a wire to one of the other VDD capacitors such as the equivalent for you as what is shown on Page 35 here: http://www.ti.com/lit/ug/spmu365c/spmu365c.pdf

0 Joseph Hancock38 over 6 years ago in reply to Ralph Jacobi

Intellectual 615 points

Hi Ralph,

I think there is a slight confusion. I have this board designed for the 1294 and want to substitute in the 1292 in place of the 1294. I do have a small number of boards but would like to avoid cutting the existing traces if it is not necessary. In my current design, pins 51 and 52 ARE connected to 3v3, 53 and 54 have 10k resistors to ground, 55 and 58 are directly tied to ground, and 59 has a 4.87k to ground.

Thanks,
Joe

0 Charles Tsai over 6 years ago in reply to Joseph Hancock38

TI__Guru**** 170706 points

Hi Joseph,
Ralph is out of office.

I think you are fine here with a 1292 drop in. By default the GPIO pins (pin 51-59 in TM4C1292) are tri-stated.

0 Joseph Hancock38 over 6 years ago in reply to Charles Tsai

Intellectual 615 points

Great! That's exactly what I wanted to know. Thank you both!

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TM4C1294NCPDT: Comparison to TM4C1292NCPDT