From f359f46ffcb4af633d3b43a108e010058ae121e8 Mon Sep 17 00:00:00 2001
From: BlackMark <me@blackmark.me>
Date: Sat, 28 May 2022 16:03:59 +0200
Subject: [PATCH] Disable interrupts while transmitting data

---
 software.hpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/software.hpp b/software.hpp
index e1019f6..fb8a3e5 100644
--- a/software.hpp
+++ b/software.hpp
@@ -4,6 +4,8 @@
 
 #include <stdint.h>
 
+#include <avr/interrupt.h>
+
 #include "../io/io.hpp"
 #include "../util/type.hpp"
 #include "../util/util.hpp"
@@ -45,6 +47,8 @@ class Software {
 
 	static word_t transfer(const word_t data)
 	{
+		const auto oldInterruptState = disableInterrupts();
+
 		auto dataIn = word_t{};
 
 		util::for_constexpr(
@@ -74,6 +78,8 @@ class Software {
 		    },
 		    util::make_index_sequence<Cfg::BITS>{});
 
+		enableInterrupts(oldInterruptState);
+
 		return dataIn;
 	}
 
@@ -89,6 +95,18 @@ class Software {
 	static io::Pin<Cfg::SS_PIN> sm_ss;
 
 	static constexpr auto DELAY_US = calcClockDelay();
+
+	static inline uint8_t disableInterrupts()
+	{
+		const auto oldInterruptState = SREG;
+		cli();
+		return oldInterruptState;
+	}
+
+	static inline void enableInterrupts(const uint8_t oldInterruptState)
+	{
+		SREG = oldInterruptState;
+	}
 };
 
 } // namespace spi