Review feedback including NO_BRIGHTNESS_COMMAND macro

29 files changed, 161 insertions, 69 deletions

diff --git a/locale/ID.po b/locale/ID.po
index 5e555a025..b211d5379 100644
--- a/locale/ID.po
+++ b/locale/ID.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -312,6 +312,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr "Kedua pin harus mendukung hardware interrut"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -443,8 +447,11 @@ msgstr "Clock unit sedang digunakan"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/circuitpython.pot b/locale/circuitpython.pot
index 67271258a..d91e2b3ac 100644
--- a/locale/circuitpython.pot
+++ b/locale/circuitpython.pot
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -308,6 +308,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -433,8 +437,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/de_DE.po b/locale/de_DE.po
index b0ebf9bcb..748833147 100644
--- a/locale/de_DE.po
+++ b/locale/de_DE.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: Pascal Deneaux\n"
 "Language-Team: Sebastian Plamauer, Pascal Deneaux\n"
@@ -312,6 +312,10 @@ msgstr "Bit depth muss ein Vielfaches von 8 sein."
 msgid "Both pins must support hardware interrupts"
 msgstr "Beide pins müssen Hardware Interrupts unterstützen"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Die Helligkeit muss zwischen 0 und 255 liegen"
@@ -437,8 +441,11 @@ msgstr "Clock unit wird benutzt"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Der Befehl muss ein int zwischen 0 und 255 sein"
 
diff --git a/locale/en_US.po b/locale/en_US.po
index 91fd15ac8..38074de98 100644
--- a/locale/en_US.po
+++ b/locale/en_US.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -308,6 +308,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -433,8 +437,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/en_x_pirate.po b/locale/en_x_pirate.po
index 5f0ab319f..9bee12d2a 100644
--- a/locale/en_x_pirate.po
+++ b/locale/en_x_pirate.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-07-27 11:55-0700\n"
 "Last-Translator: \n"
 "Language-Team: @sommersoft, @MrCertainly\n"
@@ -312,6 +312,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr ""
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr ""
@@ -437,8 +441,11 @@ msgstr ""
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr ""
 
diff --git a/locale/es.po b/locale/es.po
index ff44238df..33cdfe348 100644
--- a/locale/es.po
+++ b/locale/es.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-08-24 22:56-0500\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -316,6 +316,10 @@ msgstr "Bits depth debe ser múltiplo de 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Ambos pines deben soportar interrupciones por hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "El brillo debe estar entro 0 y 255"
@@ -441,8 +445,11 @@ msgstr "Clock unit está siendo utilizado"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Entrada de columna debe ser digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Command debe estar entre 0 y 255."
 
diff --git a/locale/fil.po b/locale/fil.po
index 4693cde64..4f05812f7 100644
--- a/locale/fil.po
+++ b/locale/fil.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-12-20 22:15-0800\n"
 "Last-Translator: Timothy <me@timothygarcia.ca>\n"
 "Language-Team: fil\n"
@@ -314,6 +314,10 @@ msgstr "Bit depth ay dapat multiple ng 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Ang parehong mga pin ay dapat na sumusuporta sa hardware interrupts"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Ang liwanag ay dapat sa gitna ng 0 o 255"
@@ -441,8 +445,11 @@ msgstr "Clock unit ginagamit"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "Sa gitna ng 0 o 255 dapat ang bytes."
diff --git a/locale/fr.po b/locale/fr.po
index db2b659dd..a948630ee 100644
--- a/locale/fr.po
+++ b/locale/fr.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: 0.1\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-04-14 20:05+0100\n"
 "Last-Translator: Pierrick Couturier <arofarn@arofarn.info>\n"
 "Language-Team: fr\n"
@@ -319,6 +319,10 @@ msgstr "La profondeur de bit doit être un multiple de 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Les deux entrées doivent supporter les interruptions matérielles"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "La luminosité doit être entre 0 et 255"
@@ -447,8 +451,11 @@ msgstr "Horloge en cours d'utilisation"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "L'entrée 'Column' doit être un digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "La commande doit être un entier entre 0 et 255"
diff --git a/locale/it_IT.po b/locale/it_IT.po
index 0e717f15b..40a685f75 100644
--- a/locale/it_IT.po
+++ b/locale/it_IT.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-10-02 16:27+0200\n"
 "Last-Translator: Enrico Paganin <enrico.paganin@mail.com>\n"
 "Language-Team: \n"
@@ -314,6 +314,10 @@ msgstr "La profondità di bit deve essere multipla di 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Entrambi i pin devono supportare gli interrupt hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "La luminosità deve essere compreso tra 0 e 255"
@@ -442,8 +446,11 @@ msgstr "Unità di clock in uso"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "I byte devono essere compresi tra 0 e 255"
diff --git a/locale/pl.po b/locale/pl.po
index 2bc1a7557..896785126 100644
--- a/locale/pl.po
+++ b/locale/pl.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: \n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-03-19 18:37-0700\n"
 "Last-Translator: Radomir Dopieralski <circuitpython@sheep.art.pl>\n"
 "Language-Team: pl\n"
@@ -311,6 +311,10 @@ msgstr "Głębia musi być wielokrotnością 8."
 msgid "Both pins must support hardware interrupts"
 msgstr "Obie nóżki muszą wspierać przerwania sprzętowe"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Jasność musi być pomiędzy 0 a 255"
@@ -436,8 +440,11 @@ msgstr "Jednostka zegara w użyciu"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Kolumny muszą być typu digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Komenda musi być int pomiędzy 0 a 255"
 
diff --git a/locale/pt_BR.po b/locale/pt_BR.po
index 7af2e3d60..7e052bfb7 100644
--- a/locale/pt_BR.po
+++ b/locale/pt_BR.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2018-10-02 21:14-0000\n"
 "Last-Translator: \n"
 "Language-Team: \n"
@@ -311,6 +311,10 @@ msgstr ""
 msgid "Both pins must support hardware interrupts"
 msgstr "Ambos os pinos devem suportar interrupções de hardware"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "O brilho deve estar entre 0 e 255"
@@ -438,8 +442,11 @@ msgstr "Unidade de Clock em uso"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr ""
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 #, fuzzy
 msgid "Command must be an int between 0 and 255"
 msgstr "Os bytes devem estar entre 0 e 255."
diff --git a/locale/zh_Latn_pinyin.po b/locale/zh_Latn_pinyin.po
index 7f6e80236..258a4d3df 100644
--- a/locale/zh_Latn_pinyin.po
+++ b/locale/zh_Latn_pinyin.po
@@ -7,7 +7,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: circuitpython-cn\n"
 "Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2019-07-19 16:09-0700\n"
+"POT-Creation-Date: 2019-07-19 16:10-0700\n"
 "PO-Revision-Date: 2019-04-13 10:10-0700\n"
 "Last-Translator: hexthat\n"
 "Language-Team: Chinese Hanyu Pinyin\n"
@@ -312,6 +312,10 @@ msgstr "Bǐtè shēndù bìxū shì 8 bèi yǐshàng."
 msgid "Both pins must support hardware interrupts"
 msgstr "Liǎng gè yǐn jiǎo dōu bìxū zhīchí yìngjiàn zhōngduàn"
 
+#: shared-bindings/displayio/Display.c
+msgid "Brightness must be 0-1.0"
+msgstr ""
+
 #: shared-bindings/supervisor/__init__.c
 msgid "Brightness must be between 0 and 255"
 msgstr "Liàngdù bìxū jiè yú 0 dào 255 zhī jiān"
@@ -437,8 +441,11 @@ msgstr "Shǐyòng shízhōng dānwèi"
 msgid "Column entry must be digitalio.DigitalInOut"
 msgstr "Liè tiáomù bìxū shì digitalio.DigitalInOut"
 
-#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/I2CDisplay.c
-#: shared-bindings/displayio/ParallelBus.c
+#: shared-bindings/displayio/I2CDisplay.c
+msgid "Command must be 0-255"
+msgstr ""
+
+#: shared-bindings/displayio/FourWire.c shared-bindings/displayio/ParallelBus.c
 msgid "Command must be an int between 0 and 255"
 msgstr "Mìnglìng bìxū shì 0 dào 255 zhī jiān de int"
 
diff --git a/ports/atmel-samd/boards/hallowing_m0_express/board.c b/ports/atmel-samd/boards/hallowing_m0_express/board.c
index 1bbbfbaf8..be1741c87 100644
--- a/ports/atmel-samd/boards/hallowing_m0_express/board.c
+++ b/ports/atmel-samd/boards/hallowing_m0_express/board.c
@@ -100,7 +100,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA00,
-        0x100, // Brightness command. Only available when <= 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pybadge/board.c b/ports/atmel-samd/boards/pybadge/board.c
index 7e6c11dd4..c9dca0329 100644
--- a/ports/atmel-samd/boards/pybadge/board.c
+++ b/ports/atmel-samd/boards/pybadge/board.c
@@ -102,7 +102,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // no brightness command
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pybadge_airlift/board.c b/ports/atmel-samd/boards/pybadge_airlift/board.c
index d7f291d7d..eeab3f2b2 100644
--- a/ports/atmel-samd/boards/pybadge_airlift/board.c
+++ b/ports/atmel-samd/boards/pybadge_airlift/board.c
@@ -80,7 +80,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // brightness command, only valid <= 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pygamer/board.c b/ports/atmel-samd/boards/pygamer/board.c
index e59b7c458..d413c8e34 100644
--- a/ports/atmel-samd/boards/pygamer/board.c
+++ b/ports/atmel-samd/boards/pygamer/board.c
@@ -102,7 +102,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // Brightness command. Only available when < 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pygamer_advance/board.c b/ports/atmel-samd/boards/pygamer_advance/board.c
index b23353998..498a29db2 100644
--- a/ports/atmel-samd/boards/pygamer_advance/board.c
+++ b/ports/atmel-samd/boards/pygamer_advance/board.c
@@ -80,7 +80,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PA01,  // backlight pin
-        0x100, // Brightness command. Only available when < 0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/pyportal/board.c b/ports/atmel-samd/boards/pyportal/board.c
index 7fffb764f..938072158 100644
--- a/ports/atmel-samd/boards/pyportal/board.c
+++ b/ports/atmel-samd/boards/pyportal/board.c
@@ -92,7 +92,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         &pin_PB31, // Backlight pin
-        0x100, // Brightness command > 0xff is none s
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness (ignored)
         true, // auto_brightness
         false, // single_byte_bounds
diff --git a/ports/atmel-samd/boards/ugame10/board.c b/ports/atmel-samd/boards/ugame10/board.c
index 27a03ad91..15e22a72c 100644
--- a/ports/atmel-samd/boards/ugame10/board.c
+++ b/ports/atmel-samd/boards/ugame10/board.c
@@ -100,7 +100,7 @@ void board_init(void) {
         display_init_sequence,
         sizeof(display_init_sequence),
         NULL,
-        0x100, // brightness command. Only valid <=0xff
+        NO_BRIGHTNESS_COMMAND,
         1.0f, // brightness
         false, // auto_brightness
         false, // single_byte_bounds
diff --git a/shared-bindings/displayio/ColorConverter.c b/shared-bindings/displayio/ColorConverter.c
index e170e0340..d9524870d 100644
--- a/shared-bindings/displayio/ColorConverter.c
+++ b/shared-bindings/displayio/ColorConverter.c
@@ -62,6 +62,8 @@ STATIC mp_obj_t displayio_colorconverter_make_new(const mp_obj_type_t *type, siz
 
 //|   .. method:: convert(color)
 //|
+//|   Converts the given RGB888 color to RGB565
+//|
 STATIC mp_obj_t displayio_colorconverter_obj_convert(mp_obj_t self_in, mp_obj_t color_obj) {
     displayio_colorconverter_t *self = MP_OBJ_TO_PTR(self_in);
 
diff --git a/shared-bindings/displayio/ColorConverter.h b/shared-bindings/displayio/ColorConverter.h
index 8f61e6642..24895500e 100644
--- a/shared-bindings/displayio/ColorConverter.h
+++ b/shared-bindings/displayio/ColorConverter.h
@@ -34,6 +34,6 @@
 extern const mp_obj_type_t displayio_colorconverter_type;
 
 void common_hal_displayio_colorconverter_construct(displayio_colorconverter_t* self);
-bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *colorconverter, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color);
+void common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *colorconverter, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color);
 
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYIO_COLORCONVERTER_H
diff --git a/shared-bindings/displayio/Display.c b/shared-bindings/displayio/Display.c
index 2586e562f..361a37ece 100644
--- a/shared-bindings/displayio/Display.c
+++ b/shared-bindings/displayio/Display.c
@@ -119,7 +119,7 @@ STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_a
         { MP_QSTR_write_ram_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2c} },
         { MP_QSTR_set_vertical_scroll, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x0} },
         { MP_QSTR_backlight_pin, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
-        { MP_QSTR_brightness_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x100} },
+        { MP_QSTR_brightness_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = NO_BRIGHTNESS_COMMAND} },
         { MP_QSTR_brightness, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = MP_OBJ_NEW_SMALL_INT(1)} },
         { MP_QSTR_auto_brightness, MP_ARG_BOOL | MP_ARG_KW_ONLY, {.u_bool = false} },
         { MP_QSTR_single_byte_bounds, MP_ARG_BOOL | MP_ARG_KW_ONLY, {.u_bool = false} },
@@ -242,10 +242,14 @@ STATIC mp_obj_t displayio_display_obj_get_brightness(mp_obj_t self_in) {
 }
 MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_get_brightness_obj, displayio_display_obj_get_brightness);
 
-STATIC mp_obj_t displayio_display_obj_set_brightness(mp_obj_t self_in, mp_obj_t brightness) {
+STATIC mp_obj_t displayio_display_obj_set_brightness(mp_obj_t self_in, mp_obj_t brightness_obj) {
     displayio_display_obj_t *self = native_display(self_in);
     common_hal_displayio_display_set_auto_brightness(self, false);
-    bool ok = common_hal_displayio_display_set_brightness(self, mp_obj_get_float(brightness));
+    mp_float_t brightness = mp_obj_get_float(brightness_obj);
+    if (brightness < 0 || brightness > 1.0) {
+        mp_raise_ValueError(translate("Brightness must be 0-1.0"));
+    }
+    bool ok = common_hal_displayio_display_set_brightness(self, brightness);
     if (!ok) {
         mp_raise_RuntimeError(translate("Brightness not adjustable"));
     }
diff --git a/shared-bindings/displayio/Display.h b/shared-bindings/displayio/Display.h
index a60a0cf5a..e765e6f25 100644
--- a/shared-bindings/displayio/Display.h
+++ b/shared-bindings/displayio/Display.h
@@ -36,6 +36,8 @@ extern const mp_obj_type_t displayio_display_type;
 
 #define DELAY 0x80
 
+#define NO_BRIGHTNESS_COMMAND 0x100
+
 void common_hal_displayio_display_construct(displayio_display_obj_t* self,
     mp_obj_t bus, uint16_t width, uint16_t height,
     int16_t colstart, int16_t rowstart, uint16_t rotation, uint16_t color_depth, bool grayscale, bool pixels_in_byte_share_row,
diff --git a/shared-bindings/displayio/I2CDisplay.c b/shared-bindings/displayio/I2CDisplay.c
index 2aac49b4d..1f74e8c9e 100644
--- a/shared-bindings/displayio/I2CDisplay.c
+++ b/shared-bindings/displayio/I2CDisplay.c
@@ -103,7 +103,7 @@ STATIC mp_obj_t displayio_i2cdisplay_make_new(const mp_obj_type_t *type, size_t
 STATIC mp_obj_t displayio_i2cdisplay_obj_send(mp_obj_t self, mp_obj_t command_obj, mp_obj_t data_obj) {
     mp_int_t command_int = MP_OBJ_SMALL_INT_VALUE(command_obj);
     if (!MP_OBJ_IS_SMALL_INT(command_obj) || command_int > 255 || command_int < 0) {
-        mp_raise_ValueError(translate("Command must be an int between 0 and 255"));
+        mp_raise_ValueError(translate("Command must be 0-255"));
     }
     uint8_t command = command_int;
     mp_buffer_info_t bufinfo;
diff --git a/shared-bindings/displayio/Palette.c b/shared-bindings/displayio/Palette.c
index 974cadb02..dda58e3c5 100644
--- a/shared-bindings/displayio/Palette.c
+++ b/shared-bindings/displayio/Palette.c
@@ -74,7 +74,7 @@ STATIC mp_obj_t displayio_palette_make_new(const mp_obj_type_t *type, size_t n_a
 STATIC mp_obj_t group_unary_op(mp_unary_op_t op, mp_obj_t self_in) {
     displayio_palette_t *self = MP_OBJ_TO_PTR(self_in);
     switch (op) {
-        case MP_UNARY_OP_BOOL: return mp_obj_new_bool(true);
+        case MP_UNARY_OP_BOOL: return mp_const_true;
         case MP_UNARY_OP_LEN:
             return MP_OBJ_NEW_SMALL_INT(common_hal_displayio_palette_get_len(self));
         default: return MP_OBJ_NULL; // op not supported
diff --git a/shared-module/displayio/ColorConverter.c b/shared-module/displayio/ColorConverter.c
index 563d40c51..6b9bd5840 100644
--- a/shared-module/displayio/ColorConverter.c
+++ b/shared-module/displayio/ColorConverter.c
@@ -57,8 +57,8 @@ bool displayio_colorconverter_convert(displayio_colorconverter_t *self, const _d
     return false;
 }
 
-bool common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
-    return displayio_colorconverter_convert(self, colorspace, input_color, output_color);
+void common_hal_displayio_colorconverter_convert(displayio_colorconverter_t *self, const _displayio_colorspace_t* colorspace, uint32_t input_color, uint32_t* output_color) {
+    displayio_colorconverter_convert(self, colorspace, input_color, output_color);
 }
 
 // Currently no refresh logic is needed for a ColorConverter.
diff --git a/shared-module/displayio/Display.c b/shared-module/displayio/Display.c
index 9aee70e32..a8515b9e5 100644
--- a/shared-module/displayio/Display.c
+++ b/shared-module/displayio/Display.c
@@ -153,7 +153,8 @@ void common_hal_displayio_display_construct(displayio_display_obj_t* self,
             common_hal_pulseio_pwmout_never_reset(&self->backlight_pwm);
         }
     }
-    if (!self->auto_brightness && (self->backlight_inout.base.type != &mp_type_NoneType || brightness_command <= 0xff)) {
+    if (!self->auto_brightness && (self->backlight_inout.base.type != &mp_type_NoneType ||
+                                   brightness_command != NO_BRIGHTNESS_COMMAND)) {
         common_hal_displayio_display_set_brightness(self, brightness);
     } else {
         self->current_brightness = -1.0;
@@ -258,7 +259,7 @@ bool common_hal_displayio_display_set_brightness(displayio_display_obj_t* self,
     } else if (self->backlight_inout.base.type == &digitalio_digitalinout_type) {
         common_hal_digitalio_digitalinout_set_value(&self->backlight_inout, brightness > 0.99);
         ok = true;
-    } else if (self->brightness_command < 0x100) {
+    } else if (self->brightness_command != NO_BRIGHTNESS_COMMAND) {
         ok = self->begin_transaction(self->bus);
         if (ok) {
             if (self->data_as_commands) {
@@ -315,17 +316,16 @@ void displayio_display_set_region_to_update(displayio_display_obj_t* self, displ
         data_length = 0;
     }
     if (self->single_byte_bounds) {
-        data[data_length] = x1 + self->colstart;
-        data[data_length + 1] = x2 - 1 + self->colstart;
+        data[data_length++] = x1 + self->colstart;
+        data[data_length++] = x2 - 1 + self->colstart;
         data_length += 2;
     } else {
         x1 += self->colstart;
         x2 += self->colstart - 1;
-        data[data_length] = x1 >> 8;
-        data[data_length + 1] = x1 & 0xff;
-        data[data_length + 2] = x2 >> 8;
-        data[data_length + 3] = x2 & 0xff;
-        data_length += 4;
+        data[data_length++] = x1 >> 8;
+        data[data_length++] = x1 & 0xff;
+        data[data_length++] = x2 >> 8;
+        data[data_length++] = x2 & 0xff;
     }
     self->send(self->bus, self->data_as_commands, data, data_length);
 
@@ -337,17 +337,15 @@ void displayio_display_set_region_to_update(displayio_display_obj_t* self, displ
         data_length = 0;
     }
     if (self->single_byte_bounds) {
-        data[data_length] = y1 + self->rowstart;
-        data[data_length + 1] = y2 - 1 + self->rowstart;
-        data_length += 2;
+        data[data_length++] = y1 + self->rowstart;
+        data[data_length++] = y2 - 1 + self->rowstart;
     } else {
         y1 += self->rowstart;
         y2 += self->rowstart - 1;
-        data[data_length] = y1 >> 8;
-        data[data_length + 1] = y1 & 0xff;
-        data[data_length + 2] = y2 >> 8;
-        data[data_length + 3] = y2 & 0xff;
-        data_length += 4;
+        data[data_length++] = y1 >> 8;
+        data[data_length++] = y1 & 0xff;
+        data[data_length++] = y2 >> 8;
+        data[data_length++] = y2 & 0xff;
     }
     self->send(self->bus, self->data_as_commands, data, data_length);
 }
diff --git a/shared-module/displayio/Palette.h b/shared-module/displayio/Palette.h
index 6f5e2774c..19c05baf5 100644
--- a/shared-module/displayio/Palette.h
+++ b/shared-module/displayio/Palette.h
@@ -53,6 +53,8 @@ typedef struct {
     bool needs_refresh;
 } displayio_palette_t;
 
+// Returns false if color fetch did not succeed (out of range or transparent).
+// Returns true if color is opaque, and sets color.
 bool displayio_palette_get_color(displayio_palette_t *palette, const _displayio_colorspace_t* colorspace, uint32_t palette_index, uint32_t* color);
 bool displayio_palette_needs_refresh(displayio_palette_t *self);
 void displayio_palette_finish_refresh(displayio_palette_t *self);
diff --git a/shared-module/displayio/TileGrid.c b/shared-module/displayio/TileGrid.c
index 77e6daf6f..88873d3a9 100644
--- a/shared-module/displayio/TileGrid.c
+++ b/shared-module/displayio/TileGrid.c
@@ -379,7 +379,7 @@ bool displayio_tilegrid_fill_area(displayio_tilegrid_t *self, const _displayio_c
             // Compute the destination pixel in the buffer and mask based on the transformations.
             int16_t offset = row_start + (x - start_x + x_shift) * x_stride; // in pixels
 
-            // This is super useful for debugging out range accesses. Uncomment to use.
+            // This is super useful for debugging out of range accesses. Uncomment to use.
             // if (offset < 0 || offset >= (int32_t) displayio_area_size(area)) {
             //     asm("bkpt");
             // }