SPI and I2C conflict when using flash for 20736

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Anonymous
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In our design,It using SPI to connect serial flash and I2C to connect a sensor IC.When download,it will fail,but if remove sensor,download will be ok.

I think the reason is SPI and I2C conflict.

How are we resovle this issue?

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1 Solution
Anonymous
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Hello Gavin,

We recently determined the conflict with the I2C expander the and the SPIFFY1 bus.

We are switching to EEPROM instead SFLASH - This has fixed the issue.

We will be updating the schematic shortly.

Sorry for the inconvenience.

Thanks

JT

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MichaelF_56
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SIP module or SoC?

Which SPI interface are you trying to use?

SPIFFY 2 is the only one that's available since SPIFFY1 shares pins with I2C. SPIFFY 2 is a lower speed interface, so I'm not sure it is ideally suited to connect to serial flash

All of this is described in the WICED™ Smart Hardware Interfaces doc.

I2C and SPIFFY2 are two seperate interfaces, so they can be used together.

Also, if you are using the SIP module, then I2C is used internally by the EEPROM that's included with the module. How are you disabling that internal EEPROM to use the serial flash externally on the low speed SPI bus?

Have you gotten this to work on the TAG3 board using the step by step instructions provided here: TAG3 Serial Flash Configuration

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Anonymous
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We don't use 20736s.

We use 20736 SPIFFY1 for serial flash,and I2C for sensor IC.For strengthen I2C driver,We use a I2C expander (LTC4313IMS8) between 20736 and sensor IC (like Wall-Mount use).

If so,SPIFFY will conflict with I2C.If remove I2C expander,it will OK.

But why is this issue.Is BRCM reference "Wall-Mount" have this issue?

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I was browsing the HW interface app note and noted the below statement on Pg14, under "Restrictions" of SPI usage. Could this be a limitation?

"4. If the application requires use of the I2C interface (for NV storage or to interface with other peripherals),

SPIFFY1 cannot be used."

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Anonymous
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I have confirmed with BRCM before our project.They said SPIFFY1 and I2C can be used together if NV storage not visit frequently.

If SPIFFY1 and I2C can't work together,why BRCM release "Wall- Mount" reference schematic?

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Anonymous
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Hello Gavin,

We recently determined the conflict with the I2C expander the and the SPIFFY1 bus.

We are switching to EEPROM instead SFLASH - This has fixed the issue.

We will be updating the schematic shortly.

Sorry for the inconvenience.

Thanks

JT

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