A port of TNKernel for PIC32
TNKernel-PIC32 is a port of TNKernel 2.7, based on the Cortex-M3 version. For a full description of the kernel API, please see the TNKernel project documentation.
##Context switch The context switch is implemented using the core software 0 interrupt. It should be configured to use the lowest priority in the system:
// set up the software interrupt 0 with a priority of 1, subpriority 0
INTSetVectorPriority(INT_CORE_SOFTWARE_0_VECTOR, INT_PRIORITY_LEVEL_1);
INTSetVectorSubPriority(INT_CORE_SOFTWARE_0_VECTOR, INT_SUB_PRIORITY_LEVEL_0);
INTEnable(INT_CS0, INT_ENABLED);
The interrupt priority level used by the context switch interrupt should not be configured to use shadow register sets.
##Interrupts TNKernel-PIC32 supports nested interrupts. The kernel provides assembly-language macros for calling C-language interrupt service routines, which can use either MIPS32 or MIPS16e mode. Both software and shadow register interrupt context saving is supported:
#include "tn_port_asm.h"
#define _CORE_TIMER_VECTOR 0
#define _TIMER1_VECTOR 4
#define _INT_UART_1_VECTOR 24
# Core timer interrupt handler using software interrupt context saving
tn_soft_isr CoreTimerHandler _CORE_TIMER_VECTOR
# High-priority UART interrupt handler using shadow register set
tn_srs_isr UartHandler _INT_UART_1_VECTOR
##Interrupt stack
TNKernel-PIC32 uses a separate stack for interrupt handlers. Switching stack pointers is done automatically in the ISR handler wrapper macros. The default size of the interrupt stack in words is set in tn_port.h:
#ifndef TN_INT_STACK_SIZE
# define TN_INT_STACK_SIZE 128
#endif
The kernel is released under the BSD license as follows:
TNKernel real-time kernel
Copyright © 2004, 2013 Yuri Tiomkin
PIC32 version modifications copyright © 2013 Anders Montonen
All rights reserved.
Permission to use, copy, modify, and distribute this software in source
and binary forms and its documentation for any purpose and without fee
is hereby granted, provided that the above copyright notice appear
in all copies and that both that copyright notice and this permission
notice appear in supporting documentation.
THIS SOFTWARE IS PROVIDED BY THE YURI TIOMKIN AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL YURI TIOMKIN OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
SUCH DAMAGE.