FXPS7140P4 un-programmed default PSI5 communication

[JOE_1209]

Hi

Can I communicate with FXPS7140P4 sensor with default setting? or it has to be programmed through PSI5 first in order to receive sensor data from it? If I can communicate with default setting then what is the default mode? asynchronous, synchronous, 10bit/16bit data, parity or CRC ?

Regards,

J

[TomasVaverka · Accepted solution]

Hi Joe,

All registers are set to 0 for any PSI5 configuration. So register 25 is 00 (PSI5_CFG). If you have a PSI5 device (FXPS7140P4), then you have to use PSI5 to use/comm to the device. With this said, the COMMTYPE bit field is set to 1 in register 16. If you try to changes this, it will produce an error so caution must be taken if you want do any over writes to the UF2 region in that this should be masked.

Best regards,

Tomas

[JOE_1209]

Hi Thomas, 

We got a few samples here from local NXP, I cannot seem to understand the register 0x40. Whenever I set USER RANGE[1:0] bit to 0x01, and programed the chip with the rest of register setting indicated by programming manual. It resulted in MEMTEMP_ERR and U_OTP_ERR, which I cannot read sensor value. (would always read 0x1EB). However, if we set the USER RANGE[1:0] to 0x00 with the same setting of the other registers (again specified by programming manual and not modifying the 0x16 COMM bit), it would read pressure value just fine, and there is no MEMTEMP_ERR & U_OTP_ERR bits set. (the voltage setting and sync pulse width all conform to the sensor manual )

As our manual dose not elaborate on USER RANGE bit, we just want to confirm that the setting of 0x00 for register 0x40 can read the range as document specified 50kPA to 126 kPA for sensor FXPS7140P4.

Regards,

Joe

[TomasVaverka]

Hi Joe,

The pressure range cannot be changed in this device otherwise it will set the errors. The intension initially was to be able to change the range if a large opportunity presented itself and this can be evaluated on a case by case bases. With this said $40, range has been revised to "Reserved". This will be updated in a future release of the datasheet which I am guessing should be ready in the end of January 22. The datasheet will have the following for this register:

The pressure range should be 40 kPa to 140 kPa.

Best regards,

Tomas

[JOE_1209]

Hi @TomasVaverka :

Hope you are doing good.

Is the official datasheet for FXPS7140P4 released yet ? We are waiting for it.

You mentioned about the release date is around end of January 2022. 

Best Regards,

Joe

[TomasVaverka]

Hi Joe,

Yes, but it can be shared under NDA only. If you have not signed the NDA with NXP yet, please create a standard case for my colleagues who are in charge of the NDA process and can eventually help you with that.

Best regards,

Tomas

[JOE_1209]

Hi Thomas,

I got one more question for you. Can I set value 0x1A to register $25. Especially, the DATA_EXT bit, it allows us to read data range between -480 to +480 LSB according to the draft document(negative 16% to positive 16% for relative pressure). I have tried writing value 0x8A to register $25, it is working fine but again according to the draft document, it only allows us to read -102 to +307 LSB (which I can only read 3% of negative pressure change and 10% of positive pressure change ).

Regards,

Joe

[JOE_1209]

Hi Tomas,

Thank you for the detailed explanation and the pressure range again. With your word, I can rest assured that there is not thing bad happening during the programming. It was me changing the value in register $40 which resulted in OTP MEM fault. Although I have broken some samples here, you save me some samples that I was going to test. Thank you. I will look forward to the release of the document for this pressure sensor.

Best Regards,

Joe

[JOE_1209]

Hi Tomas,

Thanks for your reply

Regards,

Joe