From dacc017bb67adeeabfe07e065a8b3b6ec2a286a7 Mon Sep 17 00:00:00 2001
From: Robin Giese <robin@grumpycorp.com>
Date: Mon, 24 Aug 2020 09:32:20 -0700
Subject: [PATCH] Use blocking DMA for SPI transfer

---
 Adafruit_SPIDevice.cpp | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/Adafruit_SPIDevice.cpp b/Adafruit_SPIDevice.cpp
index 081c1c1..d5ecdc9 100644
--- a/Adafruit_SPIDevice.cpp
+++ b/Adafruit_SPIDevice.cpp
@@ -114,11 +114,7 @@ void Adafruit_SPIDevice::transfer(uint8_t *buffer, size_t len) {
     // hardware SPI is easy
 
 #ifdef SPARK
-    // Spark uses asynchronous DMA for multi-byte transfers; 
-    // just use the single-byte method for sync transfers.
-    for (size_t i = 0; i < len; i++) {
-      _spi->transfer(buffer[i]);
-    }
+    _spi->transfer(buffer, buffer, len, NULL);
 #else
     _spi->transfer(buffer, len);
 #endif