Detailed Description

These definitions can be used in user application code. They may act on various types of arguments. Arguments are checked and explicit error messages are emitted.

Lower case definitions produce C code.
Upper case definitions do not produce C code.

Modules
	HWA Classes

Macros
#define	hw(...)

#define	HW_ADDRESS(...)

#define	hw_asm(...)

#define	HW_BITS(...)

#define	HW_DECLARE(...)

#define	HW_IMPLEMENT(...) HW_F(HW_IMPLEMENT,__VA_ARGS__)

#define	HW_POSITION(...)

#define	hw_stat_t(object)

#define	hw_uint_t(n)

#define	hwa(...)

Macro Definition Documentation

◆ hw

#define hw ( ... )

hw( action, object [,...] ) executes an action immediately on an object.

An explicit error message is produced if the object does not exist or if it does not support the action.
Additional arguments may follow the name of the object.

hw( configure, (porta,0), direction, output );

hw( write, counter0, 0 );

Examples: hwa/st/stm32/examples/05-2-uart/main.c.

◆ HW_ADDRESS

#define HW_ADDRESS ( ... )

Returns the address of an object or -1 if the object does not exist.

For I/O objects, the address is computed from their definition.

#if HW_ADDRESS(counter0) == -1
# error counter0 does not exist
#endif

◆ hw_asm

#define hw_asm ( ... )

Insert inline assembler code.

hw_asm("reti"); // Insert the RETI instruction

Examples: hwa/atmel/avr/examples/04-1-fade-adc/main.c.

◆ HW_BITS

#define HW_BITS ( ... )

Number of bits of an object, 0 if the object has no bits or does not exist (no error is emitted).

#if HW_BITS(counter0) != 16
# error You must chose a 16-bit counter
#endif

Examples: hwa/atmel/avr/examples/10-1-acmp/main.c.

◆ HW_DECLARE

#define HW_DECLARE ( ... )

Declares the functions that implement an object.

External objects usually rely on functions to implement their HWA actions. These functions are declared by HW_DECLARE() and implemened by HW_IMPLEMENT().

#define PCF          HW_PCF8574( interface, twi0, address, 0x27 )
 
HW_DECLARE(PCF);

An optionnal parameter 'weak' can be given so that the definitions can be overriden:

HW_DECLARE(PCF,weak);

Examples: hwa/atmel/avr/examples/99-03-HD44780-PCF8574/main.c.

◆ HW_IMPLEMENT

#define HW_IMPLEMENT ( ... ) HW_F(HW_IMPLEMENT,__VA_ARGS__)

Defines the functions that implement an object.

External objects usually rely on functions to implement their HWA actions. These functions are declared by HW_DECLARE() and defined by HW_IMPLEMENT().

#define PCF          HW_PCF8574( interface, twi0, address, 0x27 )
 
HW_IMPLEMENT(PCF);

Examples: hwa/atmel/avr/examples/99-03-HD44780-PCF8574/main.c.

◆ hw_stat_t

#define hw_stat_t ( object )

Declares the appropriate structure that holds the status of an object.

hw_stat_t(spi0) st = hw(stat,spi0);
if ( st.collision )
  ++n_collisions;

◆ hw_uint_t

#define hw_uint_t ( n )

Declares an unsigned integer.

hw_uint_t(8) expands to uint8_t;
hw_uint_t(16) expands to uint16_t.

This is useful when you need to store a value whose size depends on an object:

hw_uint_t(HW_BITS(counter0)) count = hw( read, counter0 );

Examples: hwa/atmel/avr/examples/03-5-fade-counter-compare-output/main.c.

◆ hwa

#define hwa ( ... )

hwa( action, object [,...] ) stores an action for an object into a HWA context.

An explicit error message is produced if the object does not exist or if it does not support the action.
Additional arguments may follow the name of the object.
The context must have been created, only once in the same translation unit, with hwa(begin) or hwa(begin, reset).
hwa(commit) triggers the production of the machine code.
hwa(nocommit) does not produce code but is useful to put the context in a known state.

//  Configure PA0, PA2, PA4, PA5, PA6, PA7 as outputs
//  accessing the DDRA register only once.
//
hwa( begin, reset );
hwa( configure, (porta,0), direction, output );
hwa( configure, ((porta,2)), direction, output );    // Dual parentheses is OK
hwa( configure, (port0,4,4), direction, output );
hwa( commit );

Examples: hwa/st/stm32/examples/05-2-uart/main.c.