kdebug_xmega.c

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#include <hw/hw_cpufreq.h>  /* for CPU_FREQ */
#include "hw/hw_ser.h"      /* Required for bus macros overrides */

#include "cfg/cfg_debug.h"  /* for debugging configuration settings */
#include <cfg/macros.h>     /* for BV(), DIV_ROUND */

#include <cpu/types.h>
#include <cpu/attr.h>

#include <avr/io.h>

/* Set KDBG_USART, KDBG_USART_PORT and KDBG_USART_TX_PIN_bm
 * according to the CONFIG_KDEBUG_PORT setting
 * The Xmega A and D families support at least 2 UARTS
 */
#if CONFIG_KDEBUG_PORT == 0
    #define KDBG_USART              USARTC0
    #define KDBG_USART_PORT         PORTC
    #define KDBG_USART_TX_PIN_bm    PIN3_bm
#elif CONFIG_KDEBUG_PORT == 1
    #define KDBG_USART              USARTD0
    #define KDBG_USART_PORT         PORTD
    #define KDBG_USART_TX_PIN_bm    PIN3_bm
#endif
/* Allow the configuration of the extra 3 UARTS for the
 * Xmega A family
 */
#ifdef CPU_AVR_XMEGA_A
    #if CONFIG_KDEBUG_PORT == 2
        #define KDBG_USART              USARTC1
        #define KDBG_USART_PORT         PORTC
        #define KDBG_USART_TX_PIN_bm    PIN7_bm
    #elif CONFIG_KDEBUG_PORT == 3
        #define KDBG_USART              USARTD1
        #define KDBG_USART_PORT         PORTD
        #define KDBG_USART_TX_PIN_bm    PIN7_bm
    #elif CONFIG_KDEBUG_PORT == 4
        #define KDBG_USART              USARTE0
        #define KDBG_USART_PORT         PORTE
        #define KDBG_USART_TX_PIN_bm    PIN3_bm
    #endif
#endif
/* Check if all required KDBG_ macros are defined
 */
#ifndef KDBG_USART
    #if CPU_AVR_XMEGA_D
        #error CONFIG_KDEBUG_PORT should be either 0 or 1
    #elif CPU_AVR_XMEGA_A
        #error CONFIG_KDEBUG_PORT should be either 0, 1, 2, 3 or 4
    #endif
#endif

/*
 * Scalefactor to use for computing the baudrate
 * this scalefactor should be an integer value between -7
 * and 7
 */
#ifndef KDBG_USART_SCALE_FACTOR
    #define KDBG_USART_SCALE_FACTOR (-7)
#else
    #if KDBG_USART_SCALE_FACTOR > 7 || KDBG_USART_SCALE_FACTOR < -7
        #error KDBG_USART_SCALE_FACTOR should be an integer between -7 and 7
    #endif
#endif

/*
 * \name KDBG macros
 *
 * Used to set or alter the KDB_USART operation,
 * enable the usart or send a byte.
 * Some of these methods are called/included from kdbg_hw_init()
 * others are called/included from the cpu independ kdebug implementation
 * These macros are heavily imspired by the examples provided by atmel
 *
 * \{
 */
#define KDBG_SET_FORMAT(_charSize, _parityMode, _twoStopBits)         \
    (KDBG_USART).CTRLC = (uint8_t) _charSize | _parityMode |                      \
                      (_twoStopBits ? USART_SBMODE_bm : 0)

#define KDBG_SET_BAUDRATE(_bselValue, _bScaleFactor)                  \
    (KDBG_USART).BAUDCTRLA =(uint8_t)_bselValue;                                           \
    (KDBG_USART).BAUDCTRLB =(_bScaleFactor << USART_BSCALE0_bp)|(_bselValue >> 8)

#define KDBG_TX_ENABLE()    ((KDBG_USART).CTRLB |= USART_TXEN_bm)

#define KDBG_SET_MODE(_usartMode)                                      \
    ((KDBG_USART).CTRLC = ((KDBG_USART).CTRLC & (~USART_CMODE_gm)) | _usartMode)

#define KDBG_WAIT_READY()   do{ loop_until_bit_is_set((KDBG_USART).STATUS, USART_DREIF_bp); } while(0)
#define KDBG_WAIT_TXDONE()  do { loop_until_bit_is_set((KDBG_USART).STATUS, USART_TXCIF_bp); } while(0)
#define KDBG_WRITE_CHAR(c)  do { (KDBG_USART).DATA = (c); } while(0)

#define KDBG_SET_TX_INTERRUPTLEVEL(_txdIntLevel)                      \
    (KDBG_USART).CTRLA = ((KDBG_USART).CTRLA & ~USART_TXCINTLVL_gm) | _txdIntLevel

#define KDBG_SET_DRE_INTERRUPTLEVEL(_dreIntLevel)                      \
    (KDBG_USART).CTRLA = ((KDBG_USART).CTRLA & ~USART_DREINTLVL_gm) | _dreIntLevel

/*\}*/

/*
 * To restore the USART state, to registers need to be restored
 * These registers (CTRLA and CTRLB) can be saved to the
 * kdbg_avr_xmaga_irqsave structure
 */
struct kdbg_avr_xmega_irqsave
{
    uint8_t ctrlb;
    uint8_t ctrla;
};
typedef struct kdbg_avr_xmega_irqsave kdbg_irqsave_t;

/*
 * param is the kdbg_irqsave_t structure
 *
 * * Stores the current state of the USART.CTRLA and
 * the USART.CTRLB registers
 * * Disables Transmit Complete and Date Register Empty interrupts
 * * Enabled the transmitter
 */
#define KDBG_MASK_IRQ(old)    do { \
    (old).ctrlb = KDBG_USART.CTRLB; \
    (old).ctrla = KDBG_USART.CTRLA; \
    KDBG_SET_TX_INTERRUPTLEVEL(USART_TXCINTLVL_OFF_gc); \
    KDBG_SET_DRE_INTERRUPTLEVEL(USART_DREINTLVL_OFF_gc); \
    KDBG_TX_ENABLE(); \
} while(0)

/*
 * param is the kdbg_irqsave_t structure
 *
 * * waits until all data has been transmitted
 * * restores the USART.CTRLA and USART.CTRLB registers
 */
#define KDBG_RESTORE_IRQ(old) do { \
    KDBG_WAIT_TXDONE(); \
    KDBG_USART.CTRLB = (old).ctrlb; \
    KDBG_USART.CTRLA = (old).ctrla; \
} while(0)


/*
 * method included from the cpu independent kdebug.c file.
 * it initializes KDBG_USART by:
 * * Setting the KDBG_USART_TX_PIN_bm as an outputpin
 * * Setting KDBG_USART to use 8 bits, No parity, 1 stopbit
 * * Setting the baudrate to 115200
 * * Enabeling the transmitter
 */
INLINE void kdbg_hw_init(void)
{
        //set transmit pin as output
        KDBG_USART_PORT.OUT = KDBG_USART_PORT.OUT & ~KDBG_USART_TX_PIN_bm;
        KDBG_USART_PORT.DIRSET = KDBG_USART_TX_PIN_bm;
        //set 8 bits, no parity, 1 stop bit
        KDBG_SET_FORMAT(USART_CHSIZE_8BIT_gc, USART_PMODE_DISABLED_gc, false);
        //compute and set the baud rate
        /* Compute baud-rate period, this requires a valid USART_SCALE_FACTOR */
        #if KDBG_USART_SCALE_FACTOR < 0
            uint16_t bsel = DIV_ROUND((1 << (-(KDBG_USART_SCALE_FACTOR))) * (CPU_FREQ - (16 * CONFIG_KDEBUG_BAUDRATE)), 16 * CONFIG_KDEBUG_BAUDRATE);
        #else
            uint16_t bsel = DIV_ROUND(CPU_FREQ, (1 << (KDBG_USART_SCALE_FACTOR)) * 16 * CONFIG_KDEBUG_BAUDRATE) - 1;
        #endif
        KDBG_SET_BAUDRATE(bsel, KDBG_USART_SCALE_FACTOR);
        //enable the Transmitter
        KDBG_TX_ENABLE();
}