Part Number: ADS7953
Tool/software:
Hi all
I'm working with an ADS7953 and trying to reliably read all 16 analog channels using SPI with DMA in Auto-2 mode.
While the datasheet explains the command structure well (specifically the Auto-2 start command and programming of the last channel), I’d like to get an official clarification regarding the required CS (chip select) behavior during Auto-2 operation.
In many microcontroller setups (e.g. STM32 using DMA), SPI frames are often sent as a continuous burst, means with CS held LOW for the entire duration. I initially assumed that this would be compatible with Auto-2, since the internal MUX advances automatically.
However, Figure 56 in the official ADS7953 datasheet shows clearly that CS is toggled (HIGH between each frame) during Auto-2 operation. Each 16-bit frame has a falling CS edge before and a rising edge after the transfer.
This leads me to the following questions:
1. In Auto-2 mode, is it required to toggle CS (chip select) between each 16-bit SPI frame to ensure correct channel sequencing?
2. What happens if I send 17 dummy words (e.g., 0x0000 ×17) via DMA in a single SPI burst, with CS held LOW throughout? Will the channel counter still increment reliably?
3. Are there any documented exceptions, errata, or notes for other ADS79xx family members that allow or disallow continuous CS-low operation in Auto-2 mode?
4. What would be your recommended approach for high-sample-rate ADC reading (e.g., 10 kHz full-frame update) in Auto-2 using DMA on an MCU that cannot easily toggle CS between words?
Thank you for any clarification or recommendations for robust SPI behavior in Auto-2 mode
