From 6315455dc2b20c357a906ca653054f50de134e41 Mon Sep 17 00:00:00 2001
From: ccook21 <cbcook@princeton.edu>
Date: Thu, 31 Dec 2020 10:06:47 -0700
Subject: [PATCH 1/2] fix SPI setting management

---
 TLC5947.cpp | 9 +++++++--
 TLC5947.h   | 4 ++++
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/TLC5947.cpp b/TLC5947.cpp
index ffb383d..f5e8e62 100644
--- a/TLC5947.cpp
+++ b/TLC5947.cpp
@@ -45,6 +45,8 @@ void TLC5947::init(int8_t num_latches, int8_t num_tlc_one_row, uint8_t use_2D,
   _spi_mosi = spi_mosi;
   _blank = blank;
 
+  mSettings = SPISettings(spi_baud_rate, MSBFIRST, SPI_MODE0);
+
   _use_2D = use_2D;
 
   // Initialize SPI library
@@ -71,6 +73,9 @@ void TLC5947::setSpiBaudRate(uint32_t new_baud_rate)
 {
   // Store old baud rate
   spi_baud_rate = new_baud_rate;
+
+  // update mSettings
+  mSettings = SPISettings(spi_baud_rate, MSBFIRST, SPI_MODE0);
 }
 
 uint32_t TLC5947::getSpiBaudRate()
@@ -201,7 +206,7 @@ void TLC5947::updateLeds_1D(){
   uint8_t buffer[3];
   uint16_t pwm[2];
   // ASSUMING that _grayscale_data is declared as [][LEDS_PER_CHIP][COLOR_CHANNEL_COUNT]
-  SPI.beginTransaction(SPISettings(spi_baud_rate, MSBFIRST, TLC5947_SPI_MODE));
+  SPI.beginTransaction(mSettings);
   for (int latch_index = _num_latches-1; latch_index>=0; latch_index--)
   {
     for (int chip = _num_latches * _num_tlc_one_row - (_num_latches - latch_index);
@@ -265,7 +270,7 @@ void TLC5947::updateLeds_2D(){
   // ASSUMING that _grayscale_data is declared as [][LEDS_PER_CHIP][COLOR_CHANNEL_COUNT]
   for (int latch_index = _num_latches-1; latch_index>=0; latch_index--)
   {
-    SPI.beginTransaction(SPISettings(spi_baud_rate, MSBFIRST, TLC5947_SPI_MODE));
+    SPI.beginTransaction(mSettings);
     for (int chip = _num_latches * _num_tlc_one_row - (_num_latches - latch_index);
               chip >= 0;
               chip-=_num_latches)
diff --git a/TLC5947.h b/TLC5947.h
index fb3096d..8b8fa05 100644
--- a/TLC5947.h
+++ b/TLC5947.h
@@ -35,6 +35,8 @@
 
 //#include <Arduino.h>
 #include <stdint.h>
+#include <SPI.h>
+
 // LED Current OUTPUT
 static const float LED_CURRENT_AMPS = 0.020;
 
@@ -107,6 +109,8 @@ uint8_t rgb_order_default[3] = {0, 1, 2};
   uint8_t _buffer;
   int8_t _buffer_count = 7;
   uint32_t spi_baud_rate = 1000000;
+
+  SPISettings mSettings;
 };
 
 #endif

From 95beb7c283c9d02b560227ece08af42f756cc451 Mon Sep 17 00:00:00 2001
From: Mark Harfouche <mark.harfouche@gmail.com>
Date: Fri, 2 Apr 2021 13:10:53 -0400
Subject: [PATCH 2/2] Ensure that pattern is erased when the LEDs are blanked

---
 TLC5947.cpp | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/TLC5947.cpp b/TLC5947.cpp
index f5e8e62..4ac3319 100644
--- a/TLC5947.cpp
+++ b/TLC5947.cpp
@@ -188,10 +188,6 @@ int TLC5947::enforceMaxCurrent(uint32_t * output_counts_ptr){
 void TLC5947::updateLeds(){
   uint32_t total_output_counts = 0;
   int current_too_high = enforceMaxCurrent(&total_output_counts);
-  if (total_output_counts == 0) {
-    digitalWrite(_blank, HIGH);
-    return;
-  }
   if (current_too_high != 0){
     return;
   }
@@ -201,6 +197,13 @@ void TLC5947::updateLeds(){
   } else {
     updateLeds_1D();
   }
+
+  if (total_output_counts == 0) {
+    // Setting the blank to high sets the chips into a low power state avoiding
+    // them getting hot.
+    digitalWrite(_blank, HIGH);
+    return;
+  }
 }
 void TLC5947::updateLeds_1D(){
   uint8_t buffer[3];