Can't Detect IRQ Pin Goin' High Level - ST25RU3993

[Tiago Santos]

Posted on April 19, 2018 at 21:01

Hi,

Just started to test a prototype based in the old FENTO Reader Hardware using the AS3993, now AKA ST25RU3993.

I am able to read/write registers using the SPI pins, but I cannot generate an interruption.

I have been trying to execute the interruption using two methods. First Method:

1 -Write 0x20 to Register 0x35 (Enable FIFO Interrupt)

2 - Write 0x03 to Register 0x3D (Set 48 Bytes for Transmission)

3 - Send the Comand 0x90 (Transmission with CRC)

4 - Write 4 bytes to address 0x3F, 6 times (Supplying less bytes to generate an interrupt)

Pin IRQ stays LOW.

Second one:

1 -Write 0x00 to Register 0x35 (Disable All Interrupts in this Register)

2 - Write 0x40 to Register 0x36 (Enable End of Comand Interruption)

3 - Send the Comand 0x87 (Start AD Conversion)

Pin IRQ stays LOW.

This tests are the same ones used by ST and AMS in their sample codes.

I am sure the MCU pin is working correctly and detecting the rising edge in the correct pin. Tested. I am also sure that the IRQ pin is conected to the correct pin in the MCU.

Has anyone some insights of what could be a possible cause for this problem?

[Tiago Santos]

Posted on April 20, 2018 at 16:08

As a test, I tried to read the first four positions of the FIFO, after I wrote 0x01, 0x02, 0x03 and 0x04 to them.

They return the value 0.

I am sure that the routines to read and write an array in the 3939 are correct, because I use them to validate my SPI communication. In the datasheet, page 17, it is said:

'If the register address does not exist all 0 data are sent to MISO'

The FIFO address is 0x3F. When I try to write I send the byte 0x3F - 0 0 1 1 1 1 1 1. 0 0 to write and 1 1 1 1

 1 1 1 as FIFO address.

To read I use, 0x7F - 0 1 1 1 1 1 1 1. 0 1 to read, and 1 1 1 1 1 1 as address.

[Tiago Santos · Accepted solution]

Posted on May 02, 2018 at 14:24

Hi,

Could not be able to detect the problem. Thus, I started to build my application using the FEMTO module (by AMS).

I want to validate my code first, then I'll go back to my hardware.

Well, so far I could verify the initialization, SPI, and interruptions of de ST25RU3993, using the module. I am now having a problem with the Query command. Gonna make a new question for that.