Can SPI SS pin be used as PWM output by slave?

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creet intrim
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Posted by creet intrim: Tue. Feb 23, 2021 - 10:27 AM
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Working on designing an ESC for BLDC motor and I need 6PWM. I am using ATMEGA328p-AU. I need to program the M328p after its in the PCB so I need to leave some pin outs for SPI. But some PWM and SPI pins are same. I applied a switch/buffer between MISO and MOSI. But to enable the SPI mode, I would always need the SS pin as input while also need it in PWM. What can I do?

 

If possible can I change SS pin? 

Tags:

AVR Microcontrollers, megaAVR and tinyAVR, #SPI, # Atmega328P
Last Edited: Tue. Feb 23, 2021 - 10:32 AM
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ki0bk
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Posted by ki0bk: Tue. Feb 23, 2021 - 01:40 PM
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Welcome to AVRFreaks!

 

The SS pin is not required by the SPI in master mode, although it does need to be made an output to prevent it from switching the SPI from master to slave mode.

So you can use it for any other purpose as an output pin, also you can use any other free pin as your SS output to other external SPI devices.

Hope that helps.

Jim

 

 

(Possum Lodge oath) Quando omni flunkus, moritati.

"I thought growing old would take longer"

 

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kabasan
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Posted by kabasan: Tue. Feb 23, 2021 - 01:42 PM
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Do you have a strong reason to use mega328p?

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awneil
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Posted by awneil: Tue. Feb 23, 2021 - 01:45 PM (Reply to #2)
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ki0bk wrote:
The SS pin is not required by the SPI in master mode,

It's not entirely clear to me, but isn't the OP talking about slave mode ?

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