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LMH1297EVM: MODE_SEL functionality for default functionality (Not SPI or SMBus Mode)

D P
Prodigy 10 points
Part Number: LMH1297EVM
Other Parts Discussed in Thread: LMH1297

Tool/software:

The LMH1297EVM User's Guide mentions on page 5:

5.1 Modes of Operation
The LMH1297EVM can be used in one of three modes:

1. Pin Mode (Default) – Provides general access to the LMH1297 signal integrity and I/O control settings
with IC pin-level logic.
2. SPI Mode – Provides full access to the LMH1297 signal integrity and control settings with MISO,
MOSI, SCK, and SSN pins.
3. SMBus Mode – Provides full access to the LMH1297 signal integrity and control settings with SDA,
SCL, and GND pins. ADDR0 and ADDR1 pins are used for SMBus address strap.

The LMH1297 datasheet then has the following table for the MODE_SEL pin on page 25:

This chart only specifies how to set SPI Mode or SMBus Mode.

It is not clear how to activate the Pin Mode.

So my question is, how do you activate the default Pin Mode?

  • 0
    TI__Intellectual 2875 points

    Hi, 
    I apologize for the confusion. LMH1297EVM supports pin mode at power up by reading the 4-level voltage inputs at each pin by using jumper configuration. If you want to change settings that are not available on the pin, you would have to put the EVM in SPI or SMBus mode to access the register. However, even in these modes, the EVM will still read the 4-level voltage inputs at power-up and write relevant values to the registers. 

    Please let me know if you have any other questions. 

    Best,

    J

  • 0 in reply to J
    Prodigy 10 points

    Thank you.