[GitHub] [incubator-nuttx] Ouss4 edited a comment on pull request #2674: nrf52_i2c: add support for I2C_M_NOSTOP and I2C_M_NOSTART flags

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Ouss4 edited a comment on pull request #2674:
URL: https://github.com/apache/incubator-nuttx/pull/2674#issuecomment-759608732


   > > > I see NOSTART used in various drivers, does that not expect a message without a (repeated) start?
   > > 
   > > 
   > > It doesn't expect a repeated start. NOSTART just means that the next chunk is a continuation of the old data.
   > 
   > Right, that is what I meant. I was referring to Brennan's comment regarding that none of the drivers used this feature, but I see they actually do so they would all use the memcpy() implementation.
   
   Ah ok.  Regarding the NOSTOP flag, yes, that's what makes the driver send a repeated start.  However, if my recolation is right some drivers (stm32 I believe) do send a repeated start without the NOSTOP flag.  The PIC32MZ driver needs NOSTOP to send a rpeated start.
   That said not all drivers use a repeated start, most of them do a stop (completely relinquish the bus) then a start again.
   An example of drivers using NOSTOP: https://github.com/apache/incubator-nuttx/blob/master/drivers/timers/mcp794xx.c#L298


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