SPIMaster_LDD Slave Select Always Enabled

[ttahut]

Hello, I have the SynchroMaster component using the SPIMaster_LDD configured in my project with the Slave Select enabled for the component.  I do see SPI data being transmitted when I send data using SyncCAN_SendBlock().  The problem is, the Slave Select line is always low (enabled state)- even when I am not transmitting data.  Do I have to enable/disable this pin on my own even though I have set the SPIMaster component to take control of it?  If so, how do I toggle this bit?

I running this through CodeWarrior on the FRDM-KL25Z board.

Thanks for any help.

Tom

[marek_neuzil]

Hello,

the SS pin toggling depend on the settings of CPHA bit (see the functional description of the SPI in the KL25P80M48SF0RM reference manual). When the CPHA bit is set to 0 the Chip select toggling is enabled and the SPI slave select work according to your requirement. You can see the settings of SPIMaster_LDD component on the following screenshot and the result (signals) on digital osciloscope snapshot (first channel - Chip select pin, second channel clock pin).

I have also attached the application that I have created in CW MCU 10.6.3.

Best Regards,

Marek Neuzil

[Alice_Yang]

Hi Tom,

The simple method  is configuration the "select pin " as GPIO, when transmit data, configuration it to low ,when not to transmit , high.

Use  the "BitIO" component,  use the "ClrVal" and "SetVal" set the pin to 0 and 1 .

Have a great day,
Alice

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[ttahut]

Alice- Yes that works.  But I guess I don't understand the reason the Slave Select setting is in the component if I have to toggle it on my own anyways.

In fact I got rid of the SynchroMaster because it is too slow and went straight to the SPIMaster_LDD component.  The Slave Select is in SPIMaster_LDD as well but the BitIO works as you would expect.

Thanks for your help.

[Alice_Yang]

Hi Tom,

About the "chip select toggling " on KL2x family , there is a bug , so I recommend you configuration the pin to GPIO.

The detail introduce you can refer to here :   SPI Chip select toggles between bytes , please see the talking of   xiangjun.rong  .

BR

Alice