Re: [avr-libc-dev] [RFC] Suggestion on how to rapidly implement supportfor atmega2560-2561

[Rolf Ebert]

Am Tue, 20 Sep 2005 18:59:35 +0200 schrieb Darcy Watkins  
<address@hidden>:

> Hi,
>
> OK I guess I'll need some feedback on the file.

This is just a minor remark from the Ada case.

We had good experience defining the bit numbers and corresponding masks.

#define ACD        7    // Analog Comparator Disable
#define ACD_MSK   (1<<ACD)
#define ACBG       6    // Analog Comparator Bandgap Select
#define ACBG_MSK  (1<<ACBG)
#define ACO        5    // Analog Compare Output
#define ACO_MSK   (1<<ACO)

etc.

This allows code like

   ACSR = ACI_MSK | ACIE_MSK | ACIS0_MSK;


After some time we even switched (in AVR-Ada) to define the mask with the  
bit's name and the bit number is still available with the name extended by  
_Bit.  I.e.

   --  Analog Compare Output
   ACO_Bit                  : constant Bit_Number := 5;
   ACO                      : constant Byte       := 16#20#;
   --  Analog Comparator Bandgap Select
   ACBG_Bit                 : constant Bit_Number := 6;
   ACBG                     : constant Byte       := 16#40#;
   --  Analog Comparator Disable
   ACD_Bit                  : constant Bit_Number := 7;
   ACD                      : constant Byte       := 16#80#;

Just my 0.02 Euro

   Rolf