TMP123: TMP123AIDBVR

Sahil Bhatnagar

Part Number: TMP123
Other Parts Discussed in Thread: LM70,

Hi ,

I am using TMP123AIDBVR temperature sensor and trying to interface it with the spi in our custom zynqmp board .

1. We need to know the device tree changes to register the temperature sensor with spi device

2. Can we have any source code to communicate with the temperature

We are using petalinux to create a device entry for the sensor and enabled the lm70 driver also but still stuck in it.

Kindly help us out.

Regards

Sahil

over 4 years ago

0 Ren Schackmann over 4 years ago

TI__Mastermind 43835 points

Hi Sahil,

I see that the linux kernel driver lm70 claims to support TMP123. TI had no hand in the creation of this driver, and we are not able to support it.

If you could show me an oscilloscope or logic analyzer capture of your SPI bus activity, I could comment on any problems I see there.

thanks,

ren

0 Sahil Bhatnagar over 4 years ago

Prodigy 10 points

Hi Ren,

Can we have a custom driver t solve this issue.

Also due to WFH scenerio we are remotely using the board so currently i dont have a oscilloscope capture.

Is there any other way to test it.

Regards

Sahil

0 Ren Schackmann over 4 years ago in reply to Sahil Bhatnagar

TI__Mastermind 43835 points

Hi Sahil,

You could try to activate the SPI by other means and see if you get any result. Even for that, I think you will need at least a USB logic analyzer connected to verify the activity.

ren

0 Sahil Bhatnagar over 4 years ago in reply to Ren Schackmann

Prodigy 10 points

Hi Ren,

Please find the below oscilloscope waveform captured.

we have enabled the spidev to register the temperature sensor system_user.dtsi log is below :

&spi0 {
is-decoded-cs = <0>;
num-cs = <1>;
status = "okay";
spidev@0x00 {
compatible = "spidev";
spi-max-frequency = <1000000>;
reg = <0>;
};
};

&spi1 {
is-decoded-cs = <0>;
num-cs = <1>;
status = "okay";
spidev@0x00 {
compatible = "spidev";
spi-max-frequency = <1000000>;
reg = <0>;
};
};

Then we used the spi-test application:

https://raw.githubusercontent.com/raspberrypi/linux/rpi-3.10.y/Documentation/spi/spidev_test.c

command line :

spi-test -D /dev/spidev1.0 -C where C is for chipselect.

oscilloscope capture when running spi-test application:

0 Ren Schackmann over 4 years ago in reply to Sahil Bhatnagar

TI__Mastermind 43835 points

Hi Sahil,

250ms time division is too slow. If your clock is actually 1MHz, you are looking for an event that occurs in 16us. Turn down your scope's time division to 20us or less. You will also want to increase the trigger level from 0V up to 1V or so.

thanks,

ren

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TMP123: TMP123AIDBVR