LMX2592: lmx2592 chip to communicate with the Tinypico via SPI

Joselito Go

Part Number: LMX2592
Other Parts Discussed in Thread: LMX2594, LMX2572

Hi Experts,

Good day.

I need your expertise regarding the below concern from our customer.

Using the lmx2592 chip to communicate with the Tinypico via SPI, the data waveform for sending data by viewing the oscilloscope waveform Tinypico is correct, and the waveform obtained from the lmx2592 Muxout pin by sending a reading command is correct, but whenever the Muxout pin is connected to the Tinypico chip miso pin, the Muxout pin level is pulled down below 1.8v. What do we need to pay attention to when using lmx2592's SPI output pins?

Regards,

Josel

over 3 years ago

+1 Noel Fung over 3 years ago

TI__Guru** 107230 points

Hi Josel,

Did you set MUXOUT_HDRV = 1? This will increase the MUXout output current a bit.

0 Joselito Go over 2 years ago in reply to Noel Fung

TI__Expert 5900 points

Hi Noel,

Thank you for your response.

Our customer has an additional query.
We find the register in the new version of LMX2592's datasheet.
However, we can not find the register in LMX2594. Is there the same register in LMX2594? If not, how can we config the driveability in LMX2594?

Keep safe.

Regards,

Josel

+1 Noel Fung over 2 years ago in reply to Joselito Go

TI__Guru** 107230 points

Hi Josel,

In LMX2594, we have this bit set to 1 by default, MUXout output current is already set to its maximum.

0 Joselito Go over 2 years ago in reply to Noel Fung

TI__Expert 5900 points

Hi Noel,

Thank you for your response.

Can you tell whether the output mode of LMX2592 and LMX2572 is push-pull output or open-leak output? Do we need to add a pull-up register?

Keep safe.

Regards,

Josel

+1 Noel Fung over 2 years ago in reply to Joselito Go

TI__Guru** 107230 points

Hi Josel,

MUXOUT is push-pull output, no external pull-up is required.

0 Joselito Go over 2 years ago in reply to Noel Fung

TI__Expert 5900 points

Hi Noel,

Thank you again.

Seems that customers have a lot of queries regarding this.
I have to relay another query.

The customer found that sometimes the CLK and SDI could be pulled down by the LMX2592. Could you please tell us the output mode of the CLK and SDI? Can you give me a structure of the output in the form of SCH?

Have a good day.

Regards,

Josel

0 Noel Fung over 2 years ago in reply to Joselito Go

TI__Guru** 107230 points

Hi Josel,

CLK and SDI would not be pulled low by LMX2592, the SPI interface is a slave in LMX2592. SDI, SCK and CSB are all input pins.

Clock & timing

Clock & timing forum

LMX2592: lmx2592 chip to communicate with the Tinypico via SPI