From dd639c4a029b3b31559bb4243a066e2005bdbc18 Mon Sep 17 00:00:00 2001
From: mmone <github@mmone.de>
Date: Mon, 14 May 2018 13:18:03 +0200
Subject: [PATCH] Fix wrong range of duty cycle (#1353)

The esp-idf expects duty values for the the sigma delta modulator in the range of -128 to 127
The arduino framework is supposed to use the range 0-255 thus the offset caclulation was wrong.
---
 cores/esp32/esp32-hal-sigmadelta.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cores/esp32/esp32-hal-sigmadelta.c b/cores/esp32/esp32-hal-sigmadelta.c
index 78d8c40f..4c26adaa 100644
--- a/cores/esp32/esp32-hal-sigmadelta.c
+++ b/cores/esp32/esp32-hal-sigmadelta.c
@@ -60,7 +60,7 @@ void sigmaDeltaWrite(uint8_t channel, uint8_t duty) //chan 0-7 duty 8 bit
     if(channel > 7) {
         return;
     }
-    duty += 128;
+    duty -= 128;
     SD_MUTEX_LOCK();
     SIGMADELTA.channel[channel].duty = duty;
     SD_MUTEX_UNLOCK();
@@ -72,7 +72,7 @@ uint8_t sigmaDeltaRead(uint8_t channel) //chan 0-7
         return 0;
     }
     SD_MUTEX_LOCK();
-    uint8_t duty = SIGMADELTA.channel[channel].duty - 128;
+    uint8_t duty = SIGMADELTA.channel[channel].duty + 128;
     SD_MUTEX_UNLOCK();
     return duty;
 }