From 3c7a2d5bad1f06fe5e7b33906b967b3617fd50c5 Mon Sep 17 00:00:00 2001
From: Rudolph Riedel <drone42@t-online.de>
Date: Mon, 28 Dec 2020 13:51:55 +0100
Subject: [PATCH] Added a isBusy() method to SPI calls to allow non-blocking
 polling of the DMA transfer status.

---
 libraries/SPI/SPI.cpp | 6 ++++++
 libraries/SPI/SPI.h   | 1 +
 2 files changed, 7 insertions(+)

diff --git a/libraries/SPI/SPI.cpp b/libraries/SPI/SPI.cpp
index 2b6b8321d..b315b93bd 100644
--- a/libraries/SPI/SPI.cpp
+++ b/libraries/SPI/SPI.cpp
@@ -458,6 +458,12 @@ void SPIClass::waitForTransfer(void) {
   while(dma_busy);
 }
 
+/* returns the current DMA transfer status to allow non-blocking polling */
+bool SPIClass::isBusy(void) {
+  return dma_busy;
+}
+
+
 // End DMA-based SPI transfer() code ---------------------------------------
 
 void SPIClass::attachInterrupt() {
diff --git a/libraries/SPI/SPI.h b/libraries/SPI/SPI.h
index ca1e993ac..7c719f695 100644
--- a/libraries/SPI/SPI.h
+++ b/libraries/SPI/SPI.h
@@ -120,6 +120,7 @@ class SPIClass {
   void transfer(const void* txbuf, void* rxbuf, size_t count,
          bool block = true);
   void waitForTransfer(void);
+  bool isBusy(void);
 
   // Transaction Functions
   void usingInterrupt(int interruptNumber);