Teensy 4.1 qspi

Luc

New member
I have a 4 channel high speed ADC device (TI ADS8584S ) that I am currently using in SPI mode on a teensy3.6 that I am migrating to a teensy 4.1. I would love to use it in qspi mode and get some more data throughput.

Either I am not understanding the docs, or there is no qspi other than the memory interface on the teensy 4.1. right? wrong? ( if wrong, any breadcrumbs to where I find config info in the hardware pdf)

If there is only qspi on the expansion memory pads, can I somehow use that as a qspi connection to my adc? Somehow lie to the qspi controller to configure my device, then grab data on the ready interrupt (wired to other some other pin) or poll the heck out of the 'data ready' register in qspi mapped registers? Is there automation in the qspi controller that could take any of this off my hands?

Thoughts or breadcrumbs would be very much appreciated.


Luc
 
Either I am not understanding the docs, or there is no qspi other than the memory interface on the teensy 4.1. right? wrong?

On Teensy 4.1, the only QSPI access is the bottom side pads meant for adding memory chips.


can I somehow use that as a qspi connection to my adc?

I'm not familiar with this ADC chip. But I found its datasheet here:

https://www.ti.com/product/ADS8584S

Quickly skimming the datasheet, I see only 1, 8 and 16 bit modes, especially with the timing diagrams on page 15. I don't see any 4 bit mode meant for QSPI. Did I miss something about 4 bit interface?

Another challenge with QSPI is the high clock speed. It's normally 50 MHz or more. The timing info on page 11 looks like 33 MHz max for the 8 and 16 bit modes.
 
Chips like these communicate with an SPI like interface, but they may also have multiple output pins for increasing the throughput. These extra outputs do not act in the same manner as QSPI so it's incompatible anyways, I've read somewhere that they are mainly intended for use with FPGAs. However with a Teensy 4.x it's possible to use the FlexIO interface to read the output pins simultaneously as intended for getting the increased throughput. I haven't done it myself yet but I plan on doing the same thing with a couple of ADCs I plan on using since I need the extra throughput.
 
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