--- /dev/null
+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction. Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License. This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2000 Bernardo Innocenti <bernie@codewiz.org>
+ *
+ * -->
+ *
+ * \brief ARM UART and SPI I/O driver
+ *
+ *
+ * \version $Id: ser_amr.c 18280 2007-10-11 15:14:20Z asterix $
+ * \author Daniele Basile <asterix@develer.com>
+ */
+
+#include <io/at91sam7s.h>
+
+//#include "ser_at91.h"
+#include <drv/ser.h>
+#include <drv/ser_p.h>
+
+#include <hw/hw_ser.h> /* Required for bus macros overrides */
+#include <hw/hw_cpu.h> /* CLOCK_FREQ */
+
+#include <appconfig.h>
+#include <mware/fifobuf.h>
+
+#include <cfg/debug.h>
+#include <drv/timer.h>
+
+
+//TODO
+#if !CONFIG_SER_HWHANDSHAKE
+ /**
+ * \name Hardware handshake (RTS/CTS).
+ * \{
+ */
+ #define RTS_ON do {} while (0)
+ #define RTS_OFF do {} while (0)
+ #define IS_CTS_ON true
+ #define EIMSKF_CTS 0 /**< Dummy value, must be overridden */
+ /*\}*/
+#endif
+
+#if CPU_AVR_ATMEGA1281
+ #define BIT_RXCIE0 RXCIE0
+ #define BIT_RXEN0 RXEN0
+ #define BIT_TXEN0 TXEN0
+ #define BIT_UDRIE0 UDRIE0
+
+ #define BIT_RXCIE1 RXCIE1
+ #define BIT_RXEN1 RXEN1
+ #define BIT_TXEN1 TXEN1
+ #define BIT_UDRIE1 UDRIE1
+#else
+ #define BIT_RXCIE0 RXCIE
+ #define BIT_RXEN0 RXEN
+ #define BIT_TXEN0 TXEN
+ #define BIT_UDRIE0 UDRIE
+
+ #define BIT_RXCIE1 RXCIE
+ #define BIT_RXEN1 RXEN
+ #define BIT_TXEN1 TXEN
+ #define BIT_UDRIE1 UDRIE
+#endif
+
+
+/**
+ * \name Overridable serial bus hooks
+ *
+ * These can be redefined in hw.h to implement
+ * special bus policies such as half-duplex, 485, etc.
+ *
+ *
+ * \code
+ * TXBEGIN TXCHAR TXEND TXOFF
+ * | __________|__________ | |
+ * | | | | | | | | |
+ * v v v v v v v v v
+ * ______ __ __ __ __ __ __ ________________
+ * \/ \/ \/ \/ \/ \/ \/
+ * ______/\__/\__/\__/\__/\__/\__/
+ *
+ * \endcode
+ *
+ * \{
+ */
+#ifndef SER_UART0_BUS_TXINIT
+ /**
+ * Default TXINIT macro - invoked in uart0_init()
+ *
+ * - Enable both the receiver and the transmitter
+ * - Enable only the RX complete interrupt
+ */
+ #define SER_UART0_BUS_TXINIT do { \
+ UCSR0B = BV(BIT_RXCIE0) | BV(BIT_RXEN0) | BV(BIT_TXEN0); \
+ } while (0)
+#endif
+
+#ifndef SER_UART0_BUS_TXBEGIN
+ /**
+ * Invoked before starting a transmission
+ *
+ * - Enable both the receiver and the transmitter
+ * - Enable both the RX complete and UDR empty interrupts
+ */
+ #define SER_UART0_BUS_TXBEGIN do { \
+ UCSR0B = BV(BIT_RXCIE0) | BV(BIT_UDRIE0) | BV(BIT_RXEN0) | BV(BIT_TXEN0); \
+ } while (0)
+#endif
+
+#ifndef SER_UART0_BUS_TXCHAR
+ /**
+ * Invoked to send one character.
+ */
+ #define SER_UART0_BUS_TXCHAR(c) do { \
+ UDR0 = (c); \
+ } while (0)
+#endif
+
+#ifndef SER_UART0_BUS_TXEND
+ /**
+ * Invoked as soon as the txfifo becomes empty
+ *
+ * - Keep both the receiver and the transmitter enabled
+ * - Keep the RX complete interrupt enabled
+ * - Disable the UDR empty interrupt
+ */
+ #define SER_UART0_BUS_TXEND do { \
+ UCSR0B = BV(BIT_RXCIE0) | BV(BIT_RXEN0) | BV(BIT_TXEN0); \
+ } while (0)
+#endif
+
+#ifndef SER_UART0_BUS_TXOFF
+ /**
+ * \def SER_UART0_BUS_TXOFF
+ *
+ * Invoked after the last character has been transmitted
+ *
+ * The default is no action.
+ */
+ #ifdef __doxygen__
+ #define SER_UART0_BUS_TXOFF
+ #endif
+#endif
+
+#ifndef SER_UART1_BUS_TXINIT
+ /** \sa SER_UART0_BUS_TXINIT */
+ #define SER_UART1_BUS_TXINIT do { \
+ UCSR1B = BV(BIT_RXCIE1) | BV(BIT_RXEN1) | BV(BIT_TXEN1); \
+ } while (0)
+#endif
+#ifndef SER_UART1_BUS_TXBEGIN
+ /** \sa SER_UART0_BUS_TXBEGIN */
+ #define SER_UART1_BUS_TXBEGIN do { \
+ UCSR1B = BV(BIT_RXCIE1) | BV(BIT_UDRIE1) | BV(BIT_RXEN1) | BV(BIT_TXEN1); \
+ } while (0)
+#endif
+#ifndef SER_UART1_BUS_TXCHAR
+ /** \sa SER_UART0_BUS_TXCHAR */
+ #define SER_UART1_BUS_TXCHAR(c) do { \
+ UDR1 = (c); \
+ } while (0)
+#endif
+#ifndef SER_UART1_BUS_TXEND
+ /** \sa SER_UART0_BUS_TXEND */
+ #define SER_UART1_BUS_TXEND do { \
+ UCSR1B = BV(BIT_RXCIE1) | BV(BIT_RXEN1) | BV(BIT_TXEN1); \
+ } while (0)
+#endif
+#ifndef SER_UART1_BUS_TXOFF
+ /**
+ * \def SER_UART1_BUS_TXOFF
+ *
+ * \see SER_UART0_BUS_TXOFF
+ */
+ #ifdef __doxygen__
+ #define SER_UART1_BUS_TXOFF
+ #endif
+#endif
+/*\}*/
+
+
+/**
+ * \name Overridable SPI hooks
+ *
+ * These can be redefined in hw.h to implement
+ * special bus policies such as slave select pin handling, etc.
+ *
+ * \{
+ */
+#ifndef SER_SPI_BUS_TXINIT
+ /**
+ * Default TXINIT macro - invoked in spi_init()
+ * The default is no action.
+ */
+ #define SER_SPI_BUS_TXINIT
+#endif
+
+#ifndef SER_SPI_BUS_TXCLOSE
+ /**
+ * Invoked after the last character has been transmitted.
+ * The default is no action.
+ */
+ #define SER_SPI_BUS_TXCLOSE
+#endif
+/*\}*/
+
+
+/* SPI port and pin configuration */
+#if CPU_AVR_ATMEGA64 || CPU_AVR_ATMEGA128 || CPU_AVR_ATMEGA103 || CPU_AVR_ATMEGA1281
+ #define SPI_PORT PORTB
+ #define SPI_DDR DDRB
+ #define SPI_SS_BIT PB0
+ #define SPI_SCK_BIT PB1
+ #define SPI_MOSI_BIT PB2
+ #define SPI_MISO_BIT PB3
+#elif CPU_AVR_ATMEGA8
+ #define SPI_PORT PORTB
+ #define SPI_DDR DDRB
+ #define SPI_SS_BIT PB2
+ #define SPI_SCK_BIT PB5
+ #define SPI_MOSI_BIT PB3
+ #define SPI_MISO_BIT PB4
+#else
+ #error Unknown architecture
+#endif
+
+/* USART register definitions */
+#if CPU_AVR_ATMEGA64 || CPU_AVR_ATMEGA128 || CPU_AVR_ATMEGA1281
+ #define AVR_HAS_UART1 1
+#elif CPU_AVR_ATMEGA8
+ #define AVR_HAS_UART1 0
+ #define UCSR0A UCSRA
+ #define UCSR0B UCSRB
+ #define UCSR0C UCSRC
+ #define UDR0 UDR
+ #define UBRR0L UBRRL
+ #define UBRR0H UBRRH
+ #define SIG_UART0_DATA SIG_UART_DATA
+ #define SIG_UART0_RECV SIG_UART_RECV
+ #define SIG_UART0_TRANS SIG_UART_TRANS
+#elif CPU_AVR_ATMEGA103
+ #define AVR_HAS_UART1 0
+ #define UCSR0B UCR
+ #define UDR0 UDR
+ #define UCSR0A USR
+ #define UBRR0L UBRR
+ #define SIG_UART0_DATA SIG_UART_DATA
+ #define SIG_UART0_RECV SIG_UART_RECV
+ #define SIG_UART0_TRANS SIG_UART_TRANS
+#else
+ #error Unknown architecture
+#endif
+
+
+/**
+ * \def CONFIG_SER_STROBE
+ *
+ * This is a debug facility that can be used to
+ * monitor SER interrupt activity on an external pin.
+ *
+ * To use strobes, redefine the macros SER_STROBE_ON,
+ * SER_STROBE_OFF and SER_STROBE_INIT and set
+ * CONFIG_SER_STROBE to 1.
+ */
+#if !defined(CONFIG_SER_STROBE) || !CONFIG_SER_STROBE
+ #define SER_STROBE_ON do {/*nop*/} while(0)
+ #define SER_STROBE_OFF do {/*nop*/} while(0)
+ #define SER_STROBE_INIT do {/*nop*/} while(0)
+#endif
+
+
+/* From the high-level serial driver */
+extern struct Serial ser_handles[SER_CNT];
+
+/* TX and RX buffers */
+static unsigned char uart0_txbuffer[CONFIG_UART0_TXBUFSIZE];
+static unsigned char uart0_rxbuffer[CONFIG_UART0_RXBUFSIZE];
+#if AVR_HAS_UART1
+ static unsigned char uart1_txbuffer[CONFIG_UART1_TXBUFSIZE];
+ static unsigned char uart1_rxbuffer[CONFIG_UART1_RXBUFSIZE];
+#endif
+static unsigned char spi_txbuffer[CONFIG_SPI_TXBUFSIZE];
+static unsigned char spi_rxbuffer[CONFIG_SPI_RXBUFSIZE];
+
+
+/**
+ * Internal hardware state structure
+ *
+ * The \a sending variable is true while the transmission
+ * interrupt is retriggering itself.
+ *
+ * For the USARTs the \a sending flag is useful for taking specific
+ * actions before sending a burst of data, at the start of a trasmission
+ * but not before every char sent.
+ *
+ * For the SPI, this flag is necessary because the SPI sends and receives
+ * bytes at the same time and the SPI IRQ is unique for send/receive.
+ * The only way to start transmission is to write data in SPDR (this
+ * is done by spi_starttx()). We do this *only* if a transfer is
+ * not already started.
+ */
+struct AvrSerial
+{
+ struct SerialHardware hw;
+ volatile bool sending;
+};
+
+
+/*
+ * These are to trick GCC into *not* using absolute addressing mode
+ * when accessing ser_handles, which is very expensive.
+ *
+ * Accessing through these pointers generates much shorter
+ * (and hopefully faster) code.
+ */
+struct Serial *ser_uart0 = &ser_handles[SER_UART0];
+#if AVR_HAS_UART1
+struct Serial *ser_uart1 = &ser_handles[SER_UART1];
+#endif
+struct Serial *ser_spi = &ser_handles[SER_SPI];
+
+
+
+/*
+ * Callbacks
+ */
+static void uart0_init(
+ UNUSED_ARG(struct SerialHardware *, _hw),
+ UNUSED_ARG(struct Serial *, ser))
+{
+ SER_UART0_BUS_TXINIT;
+ RTS_ON;
+ SER_STROBE_INIT;
+}
+
+static void uart0_cleanup(UNUSED_ARG(struct SerialHardware *, _hw))
+{
+ UCSR0B = 0;
+}
+
+static void uart0_enabletxirq(struct SerialHardware *_hw)
+{
+ struct AvrSerial *hw = (struct AvrSerial *)_hw;
+
+ /*
+ * WARNING: racy code here! The tx interrupt sets hw->sending to false
+ * when it runs with an empty fifo. The order of statements in the
+ * if-block matters.
+ */
+ if (!hw->sending)
+ {
+ hw->sending = true;
+ SER_UART0_BUS_TXBEGIN;
+ }
+}
+
+static void uart0_setbaudrate(UNUSED_ARG(struct SerialHardware *, _hw), unsigned long rate)
+{
+ /* Compute baud-rate period */
+ uint16_t period = (((CLOCK_FREQ / 16UL) + (rate / 2)) / rate) - 1;
+
+#if !CPU_AVR_ATMEGA103
+ UBRR0H = (period) >> 8;
+#endif
+ UBRR0L = (period);
+
+ //DB(kprintf("uart0_setbaudrate(rate=%lu): period=%d\n", rate, period);)
+}
+
+static void uart0_setparity(UNUSED_ARG(struct SerialHardware *, _hw), int parity)
+{
+#if !CPU_AVR_ATMEGA103
+ UCSR0C = (UCSR0C & ~(BV(UPM01) | BV(UPM00))) | ((parity) << UPM00);
+#endif
+}
+
+#if AVR_HAS_UART1
+
+static void uart1_init(
+ UNUSED_ARG(struct SerialHardware *, _hw),
+ UNUSED_ARG(struct Serial *, ser))
+{
+ SER_UART1_BUS_TXINIT;
+ RTS_ON;
+ SER_STROBE_INIT;
+}
+
+static void uart1_cleanup(UNUSED_ARG(struct SerialHardware *, _hw))
+{
+ UCSR1B = 0;
+}
+
+static void uart1_enabletxirq(struct SerialHardware *_hw)
+{
+ struct AvrSerial *hw = (struct AvrSerial *)_hw;
+
+ /*
+ * WARNING: racy code here! The tx interrupt
+ * sets hw->sending to false when it runs with
+ * an empty fifo. The order of the statements
+ * in the if-block matters.
+ */
+ if (!hw->sending)
+ {
+ hw->sending = true;
+ SER_UART1_BUS_TXBEGIN;
+ }
+}
+
+static void uart1_setbaudrate(UNUSED_ARG(struct SerialHardware *, _hw), unsigned long rate)
+{
+ /* Compute baud-rate period */
+ uint16_t period = (((CLOCK_FREQ / 16UL) + (rate / 2)) / rate) - 1;
+
+ UBRR1H = (period) >> 8;
+ UBRR1L = (period);
+
+ //DB(kprintf("uart1_setbaudrate(rate=%ld): period=%d\n", rate, period);)
+}
+
+static void uart1_setparity(UNUSED_ARG(struct SerialHardware *, _hw), int parity)
+{
+ UCSR1C = (UCSR1C & ~(BV(UPM11) | BV(UPM10))) | ((parity) << UPM10);
+}
+
+#endif // AVR_HAS_UART1
+
+static void spi_init(UNUSED_ARG(struct SerialHardware *, _hw), UNUSED_ARG(struct Serial *, ser))
+{
+ /*
+ * Set MOSI and SCK ports out, MISO in.
+ *
+ * The ATmega64/128 datasheet explicitly states that the input/output
+ * state of the SPI pins is not significant, as when the SPI is
+ * active the I/O port are overrided.
+ * This is *blatantly FALSE*.
+ *
+ * Moreover, the MISO pin on the board_kc *must* be in high impedance
+ * state even when the SPI is off, because the line is wired together
+ * with the KBus serial RX, and the transmitter of the slave boards
+ * would be unable to drive the line.
+ */
+ ATOMIC(SPI_DDR |= (BV(SPI_MOSI_BIT) | BV(SPI_SCK_BIT)));
+
+ /*
+ * If the SPI master mode is activated and the SS pin is in input and tied low,
+ * the SPI hardware will automatically switch to slave mode!
+ * For proper communication this pins should therefore be:
+ * - as output
+ * - as input but tied high forever!
+ * This driver set the pin as output.
+ */
+ #warning SPI SS pin set as output for proper operation, check schematics for possible conflicts.
+ ATOMIC(SPI_DDR |= BV(SPI_SS_BIT));
+
+ ATOMIC(SPI_DDR &= ~BV(SPI_MISO_BIT));
+ /* Enable SPI, IRQ on, Master */
+ SPCR = BV(SPE) | BV(SPIE) | BV(MSTR);
+
+ /* Set data order */
+ #if CONFIG_SPI_DATA_ORDER == SER_LSB_FIRST
+ SPCR |= BV(DORD);
+ #endif
+
+ /* Set SPI clock rate */
+ #if CONFIG_SPI_CLOCK_DIV == 128
+ SPCR |= (BV(SPR1) | BV(SPR0));
+ #elif (CONFIG_SPI_CLOCK_DIV == 64 || CONFIG_SPI_CLOCK_DIV == 32)
+ SPCR |= BV(SPR1);
+ #elif (CONFIG_SPI_CLOCK_DIV == 16 || CONFIG_SPI_CLOCK_DIV == 8)
+ SPCR |= BV(SPR0);
+ #elif (CONFIG_SPI_CLOCK_DIV == 4 || CONFIG_SPI_CLOCK_DIV == 2)
+ // SPR0 & SDPR1 both at 0
+ #else
+ #error Unsupported SPI clock division factor.
+ #endif
+
+ /* Set SPI2X bit (spi double frequency) */
+ #if (CONFIG_SPI_CLOCK_DIV == 128 || CONFIG_SPI_CLOCK_DIV == 64 \
+ || CONFIG_SPI_CLOCK_DIV == 16 || CONFIG_SPI_CLOCK_DIV == 4)
+ SPSR &= ~BV(SPI2X);
+ #elif (CONFIG_SPI_CLOCK_DIV == 32 || CONFIG_SPI_CLOCK_DIV == 8 || CONFIG_SPI_CLOCK_DIV == 2)
+ SPSR |= BV(SPI2X);
+ #else
+ #error Unsupported SPI clock division factor.
+ #endif
+
+ /* Set clock polarity */
+ #if CONFIG_SPI_CLOCK_POL == 1
+ SPCR |= BV(CPOL);
+ #endif
+
+ /* Set clock phase */
+ #if CONFIG_SPI_CLOCK_PHASE == 1
+ SPCR |= BV(CPHA);
+ #endif
+ SER_SPI_BUS_TXINIT;
+
+ SER_STROBE_INIT;
+}
+
+static void spi_cleanup(UNUSED_ARG(struct SerialHardware *, _hw))
+{
+ SPCR = 0;
+
+ SER_SPI_BUS_TXCLOSE;
+
+ /* Set all pins as inputs */
+ ATOMIC(SPI_DDR &= ~(BV(SPI_MISO_BIT) | BV(SPI_MOSI_BIT) | BV(SPI_SCK_BIT) | BV(SPI_SS_BIT)));
+}
+
+static void spi_starttx(struct SerialHardware *_hw)
+{
+ struct AvrSerial *hw = (struct AvrSerial *)_hw;
+
+ cpuflags_t flags;
+ IRQ_SAVE_DISABLE(flags);
+
+ /* Send data only if the SPI is not already transmitting */
+ if (!hw->sending && !fifo_isempty(&ser_spi->txfifo))
+ {
+ hw->sending = true;
+ SPDR = fifo_pop(&ser_spi->txfifo);
+ }
+
+ IRQ_RESTORE(flags);
+}
+
+static void spi_setbaudrate(
+ UNUSED_ARG(struct SerialHardware *, _hw),
+ UNUSED_ARG(unsigned long, rate))
+{
+ // nop
+}
+
+static void spi_setparity(UNUSED_ARG(struct SerialHardware *, _hw), UNUSED_ARG(int, parity))
+{
+ // nop
+}
+
+static bool tx_sending(struct SerialHardware* _hw)
+{
+ struct AvrSerial *hw = (struct AvrSerial *)_hw;
+ return hw->sending;
+}
+
+
+
+// FIXME: move into compiler.h? Ditch?
+#if COMPILER_C99
+ #define C99INIT(name,val) .name = val
+#elif defined(__GNUC__)
+ #define C99INIT(name,val) name: val
+#else
+ #warning No designated initializers, double check your code
+ #define C99INIT(name,val) (val)
+#endif
+
+/*
+ * High-level interface data structures
+ */
+static const struct SerialHardwareVT UART0_VT =
+{
+ C99INIT(init, uart0_init),
+ C99INIT(cleanup, uart0_cleanup),
+ C99INIT(setBaudrate, uart0_setbaudrate),
+ C99INIT(setParity, uart0_setparity),
+ C99INIT(txStart, uart0_enabletxirq),
+ C99INIT(txSending, tx_sending),
+};
+
+#if AVR_HAS_UART1
+static const struct SerialHardwareVT UART1_VT =
+{
+ C99INIT(init, uart1_init),
+ C99INIT(cleanup, uart1_cleanup),
+ C99INIT(setBaudrate, uart1_setbaudrate),
+ C99INIT(setParity, uart1_setparity),
+ C99INIT(txStart, uart1_enabletxirq),
+ C99INIT(txSending, tx_sending),
+};
+#endif // AVR_HAS_UART1
+
+static const struct SerialHardwareVT SPI_VT =
+{
+ C99INIT(init, spi_init),
+ C99INIT(cleanup, spi_cleanup),
+ C99INIT(setBaudrate, spi_setbaudrate),
+ C99INIT(setParity, spi_setparity),
+ C99INIT(txStart, spi_starttx),
+ C99INIT(txSending, tx_sending),
+};
+
+static struct AvrSerial UARTDescs[SER_CNT] =
+{
+ {
+ C99INIT(hw, /**/) {
+ C99INIT(table, &UART0_VT),
+ C99INIT(txbuffer, uart0_txbuffer),
+ C99INIT(rxbuffer, uart0_rxbuffer),
+ C99INIT(txbuffer_size, sizeof(uart0_txbuffer)),
+ C99INIT(rxbuffer_size, sizeof(uart0_rxbuffer)),
+ },
+ C99INIT(sending, false),
+ },
+#if AVR_HAS_UART1
+ {
+ C99INIT(hw, /**/) {
+ C99INIT(table, &UART1_VT),
+ C99INIT(txbuffer, uart1_txbuffer),
+ C99INIT(rxbuffer, uart1_rxbuffer),
+ C99INIT(txbuffer_size, sizeof(uart1_txbuffer)),
+ C99INIT(rxbuffer_size, sizeof(uart1_rxbuffer)),
+ },
+ C99INIT(sending, false),
+ },
+#endif
+ {
+ C99INIT(hw, /**/) {
+ C99INIT(table, &SPI_VT),
+ C99INIT(txbuffer, spi_txbuffer),
+ C99INIT(rxbuffer, spi_rxbuffer),
+ C99INIT(txbuffer_size, sizeof(spi_txbuffer)),
+ C99INIT(rxbuffer_size, sizeof(spi_rxbuffer)),
+ },
+ C99INIT(sending, false),
+ }
+};
+
+struct SerialHardware *ser_hw_getdesc(int unit)
+{
+ ASSERT(unit < SER_CNT);
+ return &UARTDescs[unit].hw;
+}
+
+
+/*
+ * Interrupt handlers
+ */
+
+#if CONFIG_SER_HWHANDSHAKE
+
+/// This interrupt is triggered when the CTS line goes high
+SIGNAL(SIG_CTS)
+{
+ // Re-enable UDR empty interrupt and TX, then disable CTS interrupt
+ UCSR0B = BV(RXCIE) | BV(UDRIE) | BV(RXEN) | BV(TXEN);
+ EIMSK &= ~EIMSKF_CTS;
+}
+
+#endif // CONFIG_SER_HWHANDSHAKE
+
+
+/**
+ * Serial 0 TX interrupt handler
+ */
+SIGNAL(USART0_UDRE_vect)
+{
+ SER_STROBE_ON;
+
+ struct FIFOBuffer * const txfifo = &ser_uart0->txfifo;
+
+ if (fifo_isempty(txfifo))
+ {
+ SER_UART0_BUS_TXEND;
+#ifndef SER_UART0_BUS_TXOFF
+ UARTDescs[SER_UART0].sending = false;
+#endif
+ }
+#if CPU_AVR_ATMEGA64 || CPU_AVR_ATMEGA128 || CPU_AVR_ATMEGA103
+ else if (!IS_CTS_ON)
+ {
+ // Disable rx interrupt and tx, enable CTS interrupt
+ // UNTESTED
+ UCSR0B = BV(RXCIE) | BV(RXEN) | BV(TXEN);
+ EIFR |= EIMSKF_CTS;
+ EIMSK |= EIMSKF_CTS;
+ }
+#endif
+ else
+ {
+ char c = fifo_pop(txfifo);
+ SER_UART0_BUS_TXCHAR(c);
+ }
+
+ SER_STROBE_OFF;
+}
+
+#ifdef SER_UART0_BUS_TXOFF
+/**
+ * Serial port 0 TX complete interrupt handler.
+ *
+ * This IRQ is usually disabled. The UDR-empty interrupt
+ * enables it when there's no more data to transmit.
+ * We need to wait until the last character has been
+ * transmitted before switching the 485 transceiver to
+ * receive mode.
+ *
+ * The txfifo might have been refilled by putchar() while
+ * we were waiting for the transmission complete interrupt.
+ * In this case, we must restart the UDR empty interrupt,
+ * otherwise we'd stop the serial port with some data
+ * still pending in the buffer.
+ */
+SIGNAL(SIG_UART0_TRANS)
+{
+ SER_STROBE_ON;
+
+ struct FIFOBuffer * const txfifo = &ser_uart0->txfifo;
+ if (fifo_isempty(txfifo))
+ {
+ SER_UART0_BUS_TXOFF;
+ UARTDescs[SER_UART0].sending = false;
+ }
+ else
+ UCSR0B = BV(RXCIE) | BV(UDRIE) | BV(RXEN) | BV(TXEN);
+
+ SER_STROBE_OFF;
+}
+#endif /* SER_UART0_BUS_TXOFF */
+
+
+#if AVR_HAS_UART1
+
+/**
+ * Serial 1 TX interrupt handler
+ */
+SIGNAL(USART1_UDRE_vect)
+{
+ SER_STROBE_ON;
+
+ struct FIFOBuffer * const txfifo = &ser_uart1->txfifo;
+
+ if (fifo_isempty(txfifo))
+ {
+ SER_UART1_BUS_TXEND;
+#ifndef SER_UART1_BUS_TXOFF
+ UARTDescs[SER_UART1].sending = false;
+#endif
+ }
+#if CPU_AVR_ATMEGA64 || CPU_AVR_ATMEGA128 || CPU_AVR_ATMEGA103
+ else if (!IS_CTS_ON)
+ {
+ // Disable rx interrupt and tx, enable CTS interrupt
+ // UNTESTED
+ UCSR1B = BV(RXCIE) | BV(RXEN) | BV(TXEN);
+ EIFR |= EIMSKF_CTS;
+ EIMSK |= EIMSKF_CTS;
+ }
+#endif
+ else
+ {
+ char c = fifo_pop(txfifo);
+ SER_UART1_BUS_TXCHAR(c);
+ }
+
+ SER_STROBE_OFF;
+}
+
+#ifdef SER_UART1_BUS_TXOFF
+/**
+ * Serial port 1 TX complete interrupt handler.
+ *
+ * \sa port 0 TX complete handler.
+ */
+SIGNAL(SIG_UART1_TRANS)
+{
+ SER_STROBE_ON;
+
+ struct FIFOBuffer * const txfifo = &ser_uart1->txfifo;
+ if (fifo_isempty(txfifo))
+ {
+ SER_UART1_BUS_TXOFF;
+ UARTDescs[SER_UART1].sending = false;
+ }
+ else
+ UCSR1B = BV(RXCIE) | BV(UDRIE) | BV(RXEN) | BV(TXEN);
+
+ SER_STROBE_OFF;
+}
+#endif /* SER_UART1_BUS_TXOFF */
+
+#endif // AVR_HAS_UART1
+
+
+/**
+ * Serial 0 RX complete interrupt handler.
+ *
+ * This handler is interruptible.
+ * Interrupt are reenabled as soon as recv complete interrupt is
+ * disabled. Using INTERRUPT() is troublesome when the serial
+ * is heavily loaded, because an interrupt could be retriggered
+ * when executing the handler prologue before RXCIE is disabled.
+ *
+ * \note The code that re-enables interrupts is commented out
+ * because in some nasty cases the interrupt is retriggered.
+ * This is probably due to the RXC flag being set before
+ * RXCIE is cleared. Unfortunately the RXC flag is read-only
+ * and can't be cleared by code.
+ */
+SIGNAL(USART0_RX_vect)
+{
+ SER_STROBE_ON;
+
+ /* Disable Recv complete IRQ */
+ //UCSR0B &= ~BV(RXCIE);
+ //IRQ_ENABLE;
+
+ /* Should be read before UDR */
+ ser_uart0->status |= UCSR0A & (SERRF_RXSROVERRUN | SERRF_FRAMEERROR);
+
+ /* To clear the RXC flag we must _always_ read the UDR even when we're
+ * not going to accept the incoming data, otherwise a new interrupt
+ * will occur once the handler terminates.
+ */
+ char c = UDR0;
+ struct FIFOBuffer * const rxfifo = &ser_uart0->rxfifo;
+
+ if (fifo_isfull(rxfifo))
+ ser_uart0->status |= SERRF_RXFIFOOVERRUN;
+ else
+ {
+ fifo_push(rxfifo, c);
+#if CONFIG_SER_HWHANDSHAKE
+ if (fifo_isfull(rxfifo))
+ RTS_OFF;
+#endif
+ }
+
+ /* Reenable receive complete int */
+ //IRQ_DISABLE;
+ //UCSR0B |= BV(RXCIE);
+
+ SER_STROBE_OFF;
+}
+
+
+#if AVR_HAS_UART1
+
+/**
+ * Serial 1 RX complete interrupt handler.
+ *
+ * This handler is interruptible.
+ * Interrupt are reenabled as soon as recv complete interrupt is
+ * disabled. Using INTERRUPT() is troublesome when the serial
+ * is heavily loaded, because an interrupt could be retriggered
+ * when executing the handler prologue before RXCIE is disabled.
+ *
+ * \see SIGNAL(USART1_RX_vect)
+ */
+SIGNAL(USART1_RX_vect)
+{
+ SER_STROBE_ON;
+
+ /* Disable Recv complete IRQ */
+ //UCSR1B &= ~BV(RXCIE);
+ //IRQ_ENABLE;
+
+ /* Should be read before UDR */
+ ser_uart1->status |= UCSR1A & (SERRF_RXSROVERRUN | SERRF_FRAMEERROR);
+
+ /* To avoid an IRQ storm, we must _always_ read the UDR even when we're
+ * not going to accept the incoming data
+ */
+ char c = UDR1;
+ struct FIFOBuffer * const rxfifo = &ser_uart1->rxfifo;
+ //ASSERT_VALID_FIFO(rxfifo);
+
+ if (UNLIKELY(fifo_isfull(rxfifo)))
+ ser_uart1->status |= SERRF_RXFIFOOVERRUN;
+ else
+ {
+ fifo_push(rxfifo, c);
+#if CONFIG_SER_HWHANDSHAKE
+ if (fifo_isfull(rxfifo))
+ RTS_OFF;
+#endif
+ }
+ /* Re-enable receive complete int */
+ //IRQ_DISABLE;
+ //UCSR1B |= BV(RXCIE);
+
+ SER_STROBE_OFF;
+}
+
+#endif // AVR_HAS_UART1
+
+
+/**
+ * SPI interrupt handler
+ */
+SIGNAL(SIG_SPI)
+{
+ SER_STROBE_ON;
+
+ /* Read incoming byte. */
+ if (!fifo_isfull(&ser_spi->rxfifo))
+ fifo_push(&ser_spi->rxfifo, SPDR);
+ /*
+ * FIXME
+ else
+ ser_spi->status |= SERRF_RXFIFOOVERRUN;
+ */
+
+ /* Send */
+ if (!fifo_isempty(&ser_spi->txfifo))
+ SPDR = fifo_pop(&ser_spi->txfifo);
+ else
+ UARTDescs[SER_SPI].sending = false;
+
+ SER_STROBE_OFF;
+}