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287 lines
6.5 KiB
287 lines
6.5 KiB
/** @file pio.h
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@author M. P. Hayes, UCECE
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@date 11 Jan 2006
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@brief PIO hardware abstraction for AVR microcontroller.
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@note Macros and inline functions are used to avoid function
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call overhead and to allow compile-time constant folding.
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@defgroup pio PIO driver
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This module implements a driver for general purpose I/O ports.
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Its purpose is to provide a microcontroller independent
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abstraction of a PIO pin. Here's an example:
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@code
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#include "pio.h"
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#define LED_PIO PIO_DEFINE (PORT_B, 5)
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void main (void)
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{
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system_init ();
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pio_config_set (LED_PIO, PIO_OUTPUT_LOW);
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pio_output_high (LED_PIO);
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while (1);
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}
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@endcode
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In this example, when port B5 is configured as an output it is set
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low.
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*/
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#ifndef PIO_H
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#define PIO_H
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#include "system.h"
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#include "avrtest.h"
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/** Define port names, note not all the ports are available on some AVRs. */
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enum {PORT_A, PORT_B, PORT_C, PORT_D, PORT_E, PORT_F, PORT_G};
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typedef volatile uint8_t *pio_port_t;
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typedef uint8_t pio_mask_t;
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typedef uint16_t pio_t;
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/** Define PIO pin types. The two flavours of PIO_OUTPUT are to
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ensure the port is configured without glitching due to the time
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taken before calling pio_output_set. */
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typedef enum pio_config_enum
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{
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PIO_INPUT = 1, /** Configure as input pin. */
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PIO_PULLUP, /** Configure as input pin with pullup. */
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PIO_OUTPUT_LOW, /** Configure as output, initially low. */
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PIO_OUTPUT_HIGH, /** Configure as output, initially high. */
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} pio_config_t;
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/** DDR PORT Comment
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0 0 High impedance input
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0 1 Weak pullup input
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1 0 Output low
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1 1 Output high
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*/
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/** Define a PIO as a unique 16 bit number encoding the low part of
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the PORT address in the low byte and the bit mask in the high
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byte. PORTB is used for the pattern since PORTA is not always
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defined for some AVRs. */
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#define PIO_DEFINE(PORT, PORTBIT) ((((PORT) - PORT_B) * 3) | (BIT(PORTBIT) << 8))
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/** Private macro to lookup bitmask. */
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#define PIO_BITMASK_(PIO) ((PIO) >> 8)
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/** Private macro to lookup port register. */
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#define PIO_PORT_(PIO) (&PORTB + ((PIO) & 0xff))
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/** Private macro to map a pio to its corresponding data direction
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register (DDR). NB, the DDR and PORT registers must be separated
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by the same number of bytes in all cases. PORTB is used for the
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pattern since PORTA is not always defined for some AVRs. */
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#define PIO_DDR_(PIO) (*(PIO_PORT_ (PIO) + (&DDRB - &PORTB)))
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/** Private macro to map a pio to its input register (PIN). NB, the
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PIN and PORT registers must be separated by the same number of
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bytes in all cases. PORTB is used for the pattern since PORTA is
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not always defined for some AVRs. */
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#define PIO_PIN_(pio) (*(PIO_PORT_ (pio) + (&PINB - &PORTB)))
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/** Private macro to access a pio data register. */
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#define PIO_DATA_(pio) (*PIO_PORT_ (pio))
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#ifdef DEBUG
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/** Configure pio.
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@param pio PIO to configure
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@param config PIO configuration type
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@return non-zero for success. */
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bool pio_config_set (pio_t pio, pio_config_t config);
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/** Return pio configuration
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@param pio
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@return config */
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pio_config_t pio_config_get (pio_t pio);
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/** Set pio high.
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@param pio */
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void pio_output_high (pio_t pio);
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/** Set pio low.
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@param pio */
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void pio_output_low (pio_t pio);
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/** Toggle pio.
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@param pio */
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void pio_output_toggle (pio_t pio);
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/** Read input state from pio.
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@param pio
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@return input state of pio */
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bool pio_input_get (pio_t pio);
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/** Read input state from pio.
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@param pio
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@return input state of pio */
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bool pio_input_get (pio_t pio);
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/** Get output state of pio.
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@param pio
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@return output state of pio */
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bool pio_output_get (pio_t pio);
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/** Set pio to desired state.
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@param pio
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@param state value to write pio */
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void pio_output_set (pio_t pio, bool state);
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#else
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/** Configure pio.
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@param pio PIO to configure
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@param config PIO configuration type
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@return non-zero for success. */
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static inline
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bool pio_config_set (pio_t pio, pio_config_t config)
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{
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switch (config)
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{
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case PIO_OUTPUT_LOW:
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PIO_DATA_ (pio) &= ~PIO_BITMASK_ (pio);
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PIO_DDR_ (pio) |= PIO_BITMASK_ (pio);
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return 1;
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case PIO_OUTPUT_HIGH:
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PIO_DATA_ (pio) |= PIO_BITMASK_ (pio);
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PIO_DDR_ (pio) |= PIO_BITMASK_ (pio);
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return 1;
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case PIO_INPUT:
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PIO_DDR_ (pio) &= ~PIO_BITMASK_ (pio);
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PIO_DATA_ (pio) &= ~PIO_BITMASK_ (pio);
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return 1;
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case PIO_PULLUP:
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PIO_DDR_ (pio) &= ~PIO_BITMASK_ (pio);
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PIO_DATA_ (pio) |= PIO_BITMASK_ (pio);
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return 1;
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default:
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return 0;
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}
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}
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/** Return pio configuration
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@param pio
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@return config */
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static inline
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pio_config_t pio_config_get (pio_t pio)
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{
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bool ddr;
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bool port;
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ddr = PIO_DDR_ (pio) & PIO_BITMASK_ (pio);
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port = PIO_DATA_ (pio) & PIO_BITMASK_ (pio);
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if (ddr)
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{
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if (port)
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return PIO_OUTPUT_HIGH;
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else
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return PIO_OUTPUT_LOW;
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}
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if (port)
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return PIO_PULLUP;
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return PIO_INPUT;
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}
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/** Set pio high.
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@param pio */
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static inline
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void pio_output_high (pio_t pio)
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{
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PIO_DATA_ (pio) |= PIO_BITMASK_ (pio);
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}
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/** Set pio low.
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@param pio */
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static inline
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void pio_output_low (pio_t pio)
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{
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PIO_DATA_ (pio) &= ~PIO_BITMASK_ (pio);
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}
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/** Toggle pio.
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@param pio */
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static inline
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void pio_output_toggle (pio_t pio)
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{
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PIO_DATA_ (pio) ^= PIO_BITMASK_ (pio);
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}
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/** Read input state from pio.
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@param pio
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@return input state of pio */
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static inline
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bool pio_input_get (pio_t pio)
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{
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return (PIO_PIN_ (pio) & PIO_BITMASK_ (pio)) != 0;
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}
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/** Get output state of pio.
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@param pio
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@return output state of pio */
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static inline
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bool pio_output_get (pio_t pio)
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{
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return (PIO_DATA_ (pio) & PIO_BITMASK_ (pio)) != 0;
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}
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/** Set pio to desired state.
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@param pio
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@param state value to write pio */
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static inline
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void pio_output_set (pio_t pio, bool state)
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{
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state ? pio_output_high (pio) : pio_output_low (pio);
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}
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/** Set input state for pio (this is only for use by the test scaffold).
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@param pio
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@param state value for pio input */
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static inline
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void pio_input_set (pio_t pio, bool state)
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{
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if (state)
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PIO_PIN_ (pio) |= PIO_BITMASK_ (pio);
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else
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PIO_PIN_ (pio) &= ~PIO_BITMASK_ (pio);
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}
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#endif
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#endif
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