1. Please check whether the PMODE lines are set to PMODE[2:0] = 0Z1 for SPI Boot option.
2. Can you please check the guidelines for selection of SPI in this KBA: Selection of SPI Flash Compatible with FX3/CX3/FX3S/FX2G2/SD3/SD2 and the Recommended Cypress SPI Flash Parts - KBA221833
3. What do you mean by enumeration on some boards here? are they coming up as USB Boot loader device or any other?
4. Please check the hardware guidelines for SPI Flash in the AN70707 (http://www.cypress.com/file/139936/download ).
thanks for that....
What I mean by that is some boards are able to enumerate the device, program it, boot from it and the device works normally.
On other boards, the device is not enumerated /found. I can usually program the RAM.
Pmode looks like this:
OK to float PMODE1?
The only thing I can find in the examples is on ours SCLK is pulled up with 4.7K on yours pulled down with 100K. Going to try this as it makes sense its a timing error. Anything else in the mean time?
1.State of PMODE1 pin ok.
2. There should be no pull-up or pull-down on MISO signal.
3.What do you mean by the I2C buss has pull-ups that are turned on only after the program loads?
Continue to have difficulty on some boards. The device is not found/enumerated with Cypress tool.
The part's datasheet conforms to your requirements.
The tool does not identify parts already programmed so I forced HOLD down until after init.
Usually, it still does not find it and if it does it will not program it.
I have eliminated R410 and R406 on a nonfunctional board to no avail.
Suppose its a timing error and can "fix" it by replacing the flash chip with another sometimes - but seems like a waste.
**The I2C bus is actively terminated by another device in the system. It does not come up till initialized.
For extra credit, I terminated it with 4.7K to no effect.
Thanks for your help in identifying what seems to be a timing issue with our design.
Do you have access to an Oscilloscope? As measuring what the signals are doing on good boards vs bad boards at least will point you to the right area.