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ADAS3023: How to release a latch after power up?

Question asked by Tinu on Jun 5, 2014
Latest reply on Oct 2, 2014 by maithil

Hello!

I’m running the EVAL-ADAS3023EDZ board without the EVAL-CED1Z. My target is to run the board with a STM32F107 microcontroller connected to P3.

I reconfigured the jumpers described in document UG515. Also P21 I reconfigured, written in a discussion on this forum (there is nothing written in UG515). Checking the signals directly on the ADAS3023 I recognized Pin5 and Pin40 are not connected to AGND. The datasheet differs from the circuit on the board (UG515). The pins are on 1.25V coming from the AUX circuit on the board.

Where ADAS3023 Pin5 and Pin40 should be connected (important for my own design!)?

 

To show the issue I reduced the experiment to the interconnection below.

I connected the following lines to the board P3 and test points (power):

Power supply: +15V, -15V, GND

Microcontroller: GND, RESET, PD, BUSY/SDO2 (= interrupt)

Pulsegenerator: GND, CONV (repetition rate = 100Hz)

CS = high (pull up on board)

DIN, SDO, SCK = low (pull down on board)

 

Pictures green = CONV, yellow = BUSY/SDO2, blue = RESET, red = PD

- When I power up my experiment and enable the CONV signal, every thing is fine. The ADAS3023 responses to every CONV pulse on the BUSY line (AfterPowerUp.jpg).

- When I send a PD/RESET sequence (PdResetSequence.jpg) while the CONV signal is disabled, normal operation is taken after sequence and enabling the CONV signal (AfterPowerUp.jpg)

- When I send a PD/RESET sequence (PdResetSequence.jpg) while the CONV signal is enabled, ADAS3023 stops responding on the BUSY line (Issue.jpg) due to corrupted conversion an CFG register (written in the datasheet)

 

A PD/RESET sequence with CONV enabled or disabled does not release the issue.

Also a single RESET pulse with CONV enabled or disabled does not the job.

The only solution I found (I spend a week to solve this issue) is a power cycle on the ADAS3023 to release the latch. But this will rise the complexity for me own design enormous!

Is there another solution to solve the problem?

 

Thanks for your help!

 

Regards

Martin

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