My mistake, or a possible confusion in adau1701 Datasheet?
Hello people, I have been reading again through the adau1701's datasheet. On the page 12, in the section, which describes how the WP pin works, it is written that this pin is an open collector one (in self-boot mode) and that it must be pulled high via a resistor and connected to the WP pin on a memory IC, so that when the DSP performs writing it could pull that pin low. It is also written that the Slef-Boot operation will NOT be performed, unless the WP pin is pulled high. At the same time, on the page 49, which depicts a typical self-boot schematic, the two WP pins are just directly connected without any pull-up resistor. An error? Or I do not understand something?
One more thing: ADAU1442 datasheet, page 88 and 91, the top right corner of the IC, pin 76, the "ground" symbol is missing. It presents on the same spot on pages 89 and 90, but on the pages 88 and 91 it is missing... A typo??
Audio Signal Processors
adau1442
SigmaDSP Audio Processors
adau1701
Hi Skfir,
If you look at the eval board schematic for the 1701 it shows a select switch which ties the WP high or Low for programming or operation. When I was originally going to use the 1701 for my project i used a good portion of the EVAL-ADAUMINIZ schematic so i would recommend you take a look
As for the 144x i would guess its a typo as its present on the other 2 diagrams below
Hi Gr4eme!
Yes, the evalboard schematic has a switch, but here I am talking about the chip-itself datasheet.
Sure, I have just drawn the first adau1701 schematic of mine and the eval-board schematic really helped.
Hi Skfir,
I think the WP line needs a pull-up, so this might be an error in the figure.
By the way, you only need to do anything special with the WP pin unless you plan on implementing the write back functionality into your circuit. I think if you just want to self-boot and have no need for writeback, you can just pull up the WP pin on the ADAU1701 side and pull the WP pin on the EEPROM low so it is programmable. (Of course it would be nice to put the EEPROM's WP pin high after factory programming to prevent it from being overwritten)
Regarding the ADAU1442 datasheet, yes, you are correct. The ground symbol is missing from figures 63 and 66. I'll request that to be updated.
Hi BrettG!
Thanks for your reply. Since I am not an engineer, I was not certain about those figures, so I am very glad that was correct, despite my more than limited knowledge on the matter. What is about the WB configuration, I have done as you said, since I plan to use potentiometers and hope to make the firmware without anything requiring this function, I tied WP pin on the memory module to the ground and on the DSP to the VDD.
What is about the factory programming, I am just building the first non-breadboard prototype, so as we Russians say in such cases - it is as far until the factory programming, as it is for a crab to walk to China. But hope this moment will come once. Thank you again Brett!
You're welcome! Let us know if you need further help with your design.
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