Chip Select always high in SPI interface

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hrg
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Chip Select always high in SPI interface

Hi Dialog Team ,

Finally we planned to use SPI flash to use instead of OTP. As you mentioned in my another question http://support.dialog-semiconductor.com/spi-eeprom-interface we got adesto AT25XE011 SPI Flash. We interfaced and checked with Pheriperal example project. Da14580 couldnt able to read or write the flash.On further analysis we noticed that when the code is dumped (before execution) Port0_3 (Chipselect) is 2.9 volts ,when the code is executing ,during the call of spi_cs_low(); the cs pin is not goin to zero there is some voltage of 0.9 volts .
Though the DA14580 is operating in 1.5volt , SPIflash at 1.7 volt ,there is some higher voltage of 2.9 volts across the CS pin (P0_3).I guess it is from mother board ! We are following the pheripheral examples UB-005 & the jumper settings seems to be fine . But still CS pin is not going LOW(zero) ! Could you please replicate or explain why such leakage is happening!

Thankyou

FH_Dialog
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Hi Hrg 

Hi Hrg 

Can you please do simple experiment that remove jumper for CS pin and measure the voltage at pin to see if voltage is correct in 580 side? that will help to see leakage from mother board or not. 

 

hrg
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Hi FH_Dialog

Hi FH_Dialog

The voltage measured on the Port0_3 without connecting to CS of SPIflash is 2.9 volts and when the code is executing it goes to 0.97 volts .Though SPI flash operates at 1.8 volt & DA14580 is configured to work on boost mode with 1.5 volts , the P0_3 measures 2.9 volts ! !

JE_Dialog
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Hello hrg, when you are

Hello hrg, when you are measing the voltages - are you measuring with a scope of multimeter ? if the pins are toggling/communicating, then DMM will read an average : using a scope to see what is happenign on the SPI or logic analyser is preferable. Also, even though you are using BOOST mode, remember you have also internal boost converter .

BR JE_DIalog

hrg
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Thankyou JE_Dialog . So you

Thankyou JE_Dialog . So you mean that a stand alone DA chip with boost configuration may have such range of voltage if we use any GPIO as CS pin ?

JE_Dialog
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Hello hrg, the voltage will

Hello hrg, the voltage will be 3V  (boost output) if it was static high, 0V if static low : then if you are measing with a DMM, you will see an average - that value depending upon how the meter is measuring... therefore, i'd recommend to put a scope on it to see teh true activity.

BR JE_Dialog

hrg
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Thankyou JE_dialog .

Thankyou JE_dialog .