From 6db318828dda2c3bb8858c996e97c42355f055dc Mon Sep 17 00:00:00 2001
From: Jason Smith <jason.inet@gmail.com>
Date: Sun, 3 Nov 2019 23:22:11 -0800
Subject: [PATCH] Add function to set SoftwareSerial int priority

---
 libraries/SoftwareSerial/src/SoftwareSerial.cpp | 10 ++++++++++
 libraries/SoftwareSerial/src/SoftwareSerial.h   |  4 ++++
 2 files changed, 14 insertions(+)

diff --git a/libraries/SoftwareSerial/src/SoftwareSerial.cpp b/libraries/SoftwareSerial/src/SoftwareSerial.cpp
index 9ba9dbb731..104f9150aa 100644
--- a/libraries/SoftwareSerial/src/SoftwareSerial.cpp
+++ b/libraries/SoftwareSerial/src/SoftwareSerial.cpp
@@ -35,6 +35,7 @@
 // Includes
 //
 #include "SoftwareSerial.h"
+#include <timer.h>
 
 #define OVERSAMPLE 3 // in RX, Timer will generate interruption OVERSAMPLE time during a bit. Thus OVERSAMPLE ticks in a bit. (interrupt not synchonized with edge).
 
@@ -96,6 +97,8 @@
 // Statics
 //
 HardwareTimer SoftwareSerial::timer(TIMER_SERIAL);
+const IRQn_Type SoftwareSerial::timer_interrupt_number = static_cast<IRQn_Type>(getTimerUpIrq(TIMER_SERIAL));
+uint32_t SoftwareSerial::timer_interrupt_priority = NVIC_EncodePriority(NVIC_GetPriorityGrouping(), TIM_IRQ_PRIO, TIM_IRQ_SUBPRIO);
 SoftwareSerial *SoftwareSerial::active_listener = nullptr;
 SoftwareSerial *volatile SoftwareSerial::active_out = nullptr;
 SoftwareSerial *volatile SoftwareSerial::active_in = nullptr;
@@ -107,6 +110,12 @@ uint32_t SoftwareSerial::rx_buffer = 0;
 int32_t SoftwareSerial::rx_bit_cnt = -1; // rx_bit_cnt = -1 :  waiting for start bit
 uint32_t SoftwareSerial::cur_speed = 0;
 
+void SoftwareSerial::setInterruptPriority(uint32_t preemptPriority, uint32_t subPriority)
+{
+  timer_interrupt_priority = NVIC_EncodePriority(NVIC_GetPriorityGrouping(), preemptPriority, subPriority);
+  NVIC_SetPriority(timer_interrupt_number, timer_interrupt_priority);
+}
+
 //
 // Private methods
 //
@@ -134,6 +143,7 @@ void SoftwareSerial::setSpeed(uint32_t speed)
       timer.setCount(0);
       timer.attachInterrupt(&handleInterrupt);
       timer.resume();
+      NVIC_SetPriority(timer_interrupt_number, timer_interrupt_priority);
     } else {
       timer.detachInterrupt();
     }
diff --git a/libraries/SoftwareSerial/src/SoftwareSerial.h b/libraries/SoftwareSerial/src/SoftwareSerial.h
index 7ec0aee188..45b0c03c9f 100644
--- a/libraries/SoftwareSerial/src/SoftwareSerial.h
+++ b/libraries/SoftwareSerial/src/SoftwareSerial.h
@@ -66,6 +66,8 @@ class SoftwareSerial : public Stream {
     // static data
     static bool initialised;
     static HardwareTimer timer;
+    static const IRQn_Type timer_interrupt_number;
+    static uint32_t timer_interrupt_priority;
     static SoftwareSerial *active_listener;
     static SoftwareSerial *volatile active_out;
     static SoftwareSerial *volatile active_in;
@@ -118,6 +120,8 @@ class SoftwareSerial : public Stream {
       return true;
     }
 
+    static void setInterruptPriority(uint32_t preemptPriority, uint32_t subPriority);
+
     using Print::write;
 };