ADS61B23: ADS61B23 SERIAL INTERFACE

Hi Zlatko

Zlatko Pikal said:

When utilizing the ADC serial interface, what is the maximum period that reset can be asserted to logic ‘1’ before the ADC reverts to parallel configuration mode ?

There is only a minimum period as specified in Figure 6 of the document below to ensure correct state of the serial interface mode. 

Could you please make sure that your SCLK, SDATA, and SEN are in known 0 or AVDD value to ensure if you extend the reset condition, that the serial interface mode configuration will be as close to the parallel configuration mode?

Zlatko Pikal said:

When utilizing the serial interface configuration mode, with respect to config word 00, is there a wait time required if bit[4] is asserted (reset) before configuring the next word ?

Same condition on T3 as Figure 6 can be applied. 

Thanks for the quick reply.

Let me formulate question differently.

We do not want to use parallel interface at all.

We want to control all registers via software.

So first question is can we lock PDN and RST pins low and issue register initialization via SPI port. (bit D4 in register 0)

Basically from data sheet it is not perfectly clear if RST pin has to be toggled high to initialize registers and SPI bus controller or we can just lock PDN and RST low and still be able to use SPI port and initialize registers by using D4 in register 0.

Is operation of ADC SPI port somehow tied to RST pin being toggled high low at least once?.

Cheers

Zlatko

Hello Pikal,

Thank you. I understand that you only wanted to use SPI serial interface to program the ADC.

Yes, you can connect both PDN and RST to ground and issue <RST> via SPI port. This is one of the option mentioned below. 

Great.

Just one more clarification regarding SPI bus.

Do we have to initialize internal registers only once on a power up (using RESET pin or bit D4 in register 0) or we have to keep initializing them on every SPI write to any register?

Serial interface timing diagram on page 13 shows only one SPI write cycle.

There are 8 registers that we need to program.

So can we just initialize the internal register once or we have to do it for every SPI write cycle (every register)?

Thanks

Zlatko Pikal