211 lines
9.7 KiB
C
211 lines
9.7 KiB
C
// #################################################################################################
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// # << NEORV32 - External Interrupt Controller (XIRQ) Demo Program >> #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License #
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// # #
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// # Copyright (c) 2023, Stephan Nolting. All rights reserved. #
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// # #
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// # Redistribution and use in source and binary forms, with or without modification, are #
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// # permitted provided that the following conditions are met: #
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// # #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of #
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// # conditions and the following disclaimer. #
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// # #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of #
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// # conditions and the following disclaimer in the documentation and/or other materials #
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// # provided with the distribution. #
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// # #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to #
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// # endorse or promote products derived from this software without specific prior written #
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// # permission. #
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// # #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS #
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// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, #
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// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED #
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// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED #
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// # OF THE POSSIBILITY OF SUCH DAMAGE. #
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// # ********************************************************************************************* #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32 (c) Stephan Nolting #
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// #################################################################################################
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/**********************************************************************//**
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* @file demo_xirq/main.c
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* @author Stephan Nolting
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* @brief External interrupt controller (XIRQ) demo program (using hardware-assisted prioritization).
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**************************************************************************/
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#include <neorv32.h>
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/**********************************************************************//**
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* @name User configuration
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**************************************************************************/
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/**@{*/
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/** UART BAUD rate */
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#define BAUD_RATE 19200
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/**@}*/
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// prototypes
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void xirq_handler_ch0(void);
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void xirq_handler_ch1(void);
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void xirq_handler_ch2(void);
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void xirq_handler_ch3(void);
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/**********************************************************************//**
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* Main function
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*
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* @note This program requires the XIRQ and the UART to be synthesized.
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*
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* @return 0 if execution was successful
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**************************************************************************/
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int main() {
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// initialize the neorv32 runtime environment
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// this will take care of handling all CPU traps (interrupts and exceptions)
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neorv32_rte_setup();
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// setup UART0 at default baud rate, no parity bits, no HW flow control
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neorv32_uart0_setup(BAUD_RATE, PARITY_NONE, FLOW_CONTROL_NONE);
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// check if XIRQ unit is implemented at all
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if (neorv32_xirq_available() == 0) {
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neorv32_uart0_printf("XIRQ not synthesized!\n");
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return 1;
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}
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// intro
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neorv32_uart0_printf("External interrupt controller (XIRQ) demo program\n\n");
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int err_cnt = 0;
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// initialize XIRQ controller
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// this will disable all XIRQ channels and will also clear any pending external interrupts
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// (details: this will register the XIRQ's second-level interrupt handler in the NEORV32 RTE)
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err_cnt = neorv32_xirq_setup();
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// check if setup went fine
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if (err_cnt) {
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neorv32_uart0_printf("Error during XIRQ setup!\n");
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return 1;
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}
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// install handler functions for XIRQ channel 0,1,2,3. note that these functions are "normal" functions!
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// (details: these are "third-level" interrupt handlers)
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// neorv32_xirq_install() also enables the specified XIRQ channel and clears any pending interrupts
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err_cnt = 0;
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err_cnt += neorv32_xirq_install(0, xirq_handler_ch0); // handler function for channel 0
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err_cnt += neorv32_xirq_install(1, xirq_handler_ch1); // handler function for channel 1
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err_cnt += neorv32_xirq_install(2, xirq_handler_ch2); // handler function for channel 2
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err_cnt += neorv32_xirq_install(3, xirq_handler_ch3); // handler function for channel 3
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// check if installation went fine
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if (err_cnt) {
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neorv32_uart0_printf("Error during XIRQ install!\n");
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return 1;
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}
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// allow XIRQ to trigger CPU interrupt
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neorv32_xirq_global_enable();
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// enable machine-mode interrupts
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neorv32_cpu_csr_set(CSR_MSTATUS, 1 << CSR_MSTATUS_MIE);
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// the code below assumes the XIRQ inputs are connected to the processor's GPIO output port
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// so we can trigger the IRQs from software; if you have connected the XIRQs to buttons you
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// can remove the code below (note the trigger configuration using the XIRQ generics!)
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{
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// trigger XIRQs 3:0 at once
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// assumes xirq_i(31:0) <= gpio.output(31:0)
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// due to the prioritization this will execute
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// -> xirq_handler_ch0
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// -> xirq_handler_ch1
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// -> xirq_handler_ch2
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// -> xirq_handler_ch3
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neorv32_gpio_port_set(0xF); // set output pins 3:0 -> trigger XIRQ 3:0
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neorv32_gpio_port_set(0x0);
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}
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// --- wait for interrupts ---
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// All incoming XIRQ interrupt requests are "prioritized" in this example. The XIRQ FIRQ handler
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// reads the ID of the interrupt with the highest priority from the XIRQ controller ("source" register) and calls the according
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// handler function (installed via neorv32_xirq_install();).
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// Non-prioritized handling of interrupts (or custom prioritization) can be implemented by manually reading the
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// XIRQ controller's "pending" register. Then it is up to the software to define which pending IRQ should be served first.
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while(1);
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// just as an example: to disable certain XIRQ interrupt channels, we can
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// un-install the according handler. this will also clear a pending interrupt for that channel
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neorv32_xirq_uninstall(0); // disable XIRQ channel 0 and remove associated handler
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neorv32_xirq_uninstall(1); // disable XIRQ channel 1 and remove associated handler
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neorv32_xirq_uninstall(2); // disable XIRQ channel 2 and remove associated handler
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neorv32_xirq_uninstall(3); // disable XIRQ channel 3 and remove associated handler
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// you can also manually clear pending interrupts
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neorv32_xirq_clear_pending(0); // clear pending interrupt of channel 0
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// manually enable and disable XIRQ channels
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neorv32_xirq_channel_enable(0); // enable channel 0
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neorv32_xirq_channel_disable(0); // disable channel 0
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// globally enable/disable XIRQ CPU interrupt
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// this will not affect the XIR configuration / pending interrupts
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neorv32_xirq_global_enable();
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neorv32_xirq_global_disable();
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return 0;
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}
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/**********************************************************************//**
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* XIRQ handler channel 0.
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*
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* @warning This function has to be of type "void xyz(void)" and must not use any interrupt attributes!
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**************************************************************************/
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void xirq_handler_ch0(void) {
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neorv32_uart0_printf("XIRQ interrupt from channel %i\n", 0);
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}
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/**********************************************************************//**
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* XIRQ handler channel 1.
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*
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* @warning This function has to be of type "void xyz(void)" and must not use any interrupt attributes!
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**************************************************************************/
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void xirq_handler_ch1(void) {
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neorv32_uart0_printf("XIRQ interrupt from channel %i\n", 1);
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}
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/**********************************************************************//**
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* XIRQ handler channel 2.
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*
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* @warning This function has to be of type "void xyz(void)" and must not use any interrupt attributes!
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**************************************************************************/
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void xirq_handler_ch2(void) {
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neorv32_uart0_printf("XIRQ interrupt from channel %i\n", 2);
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}
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/**********************************************************************//**
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* XIRQ handler channel 3.
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*
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* @warning This function has to be of type "void xyz(void)" and must not use any interrupt attributes!
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**************************************************************************/
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void xirq_handler_ch3(void) {
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neorv32_uart0_printf("XIRQ interrupt from channel %i\n", 3);
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}
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