Rework displays in prep for dynamic support and 8bit parallel.

6 files changed, 376 insertions, 70 deletions

diff --git a/shared-bindings/displayio/Display.c b/shared-bindings/displayio/Display.c
new file mode 100644
index 000000000..5db470417
--- /dev/null
+++ b/shared-bindings/displayio/Display.c
@@ -0,0 +1,149 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/displayio/Display.h"
+
+#include <stdint.h>
+
+#include "lib/utils/context_manager_helpers.h"
+#include "py/binary.h"
+#include "py/objproperty.h"
+#include "py/runtime.h"
+#include "shared-bindings/displayio/Group.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/util.h"
+#include "shared-module/displayio/__init__.h"
+#include "supervisor/shared/translate.h"
+
+//| .. currentmodule:: displayio
+//|
+//| :class:`FourWire` -- Manage updating a display over SPI four wire protocol
+//| ==========================================================================
+//|
+//| Manage updating a display over SPI four wire protocol in the background while Python code runs.
+//| It doesn't handle display initialization.
+//|
+//| .. warning:: This will be changed before 4.0.0. Consider it very experimental.
+//|
+//| .. class:: Display(display_bus, *, width, height, colstart=0, rowstart=0, color_depth=16,
+//|                    set_column_command=0x2a set_row_command=0x2b, write_ram_command=0x2c)
+//|
+//|   Create a FourWire object associated with the given pins.
+//|
+STATIC mp_obj_t displayio_display_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_display_bus, ARG_init_sequence, ARG_width, ARG_height, ARG_colstart, ARG_rowstart, ARG_color_depth, ARG_set_column_command, ARG_set_row_command, ARG_write_ram_command };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_display_bus, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_init_sequence, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_width, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = -1} },
+        { MP_QSTR_height, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = -1} },
+        { MP_QSTR_colstart, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0} },
+        { MP_QSTR_rowstart, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0} },
+        { MP_QSTR_color_depth, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 16} },
+        { MP_QSTR_set_column_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2a} },
+        { MP_QSTR_set_row_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2b} },
+        { MP_QSTR_write_ram_command, MP_ARG_INT | MP_ARG_KW_ONLY, {.u_int = 0x2c} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mp_obj_t display_bus = args[ARG_display_bus].u_obj;
+
+    mp_int_t width = args[ARG_width].u_int;
+    mp_int_t height = args[ARG_height].u_int;
+    if (width == -1 || height == -1) {
+        mp_raise_ValueError(translate("Width and height kwargs required"));
+    }
+    mp_buffer_info_t bufinfo;
+    mp_get_buffer_raise(args[ARG_init_sequence].u_obj, &bufinfo, MP_BUFFER_READ);
+
+    displayio_display_obj_t *self;
+    if (display_bus == &primary_display.fourwire_bus) {
+        self = &primary_display.display;
+    } else {
+        self = m_new_obj(displayio_display_obj_t);
+    }
+    self->base.type = &displayio_display_type;
+    common_hal_displayio_display_construct(self,
+            display_bus, width, height, args[ARG_colstart].u_int, args[ARG_rowstart].u_int,
+            args[ARG_color_depth].u_int, args[ARG_set_column_command].u_int, args[ARG_set_row_command].u_int,
+            args[ARG_write_ram_command].u_int, bufinfo.buf, bufinfo.len);
+
+    return self;
+}
+
+//|   .. method:: show(group)
+//|
+//|     Switches to displaying the given group of layers.
+//|
+STATIC mp_obj_t displayio_display_obj_show(mp_obj_t self_in, mp_obj_t group_in) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_t native_layer = mp_instance_cast_to_native_base(group_in, &displayio_group_type);
+    if (native_layer == MP_OBJ_NULL) {
+        mp_raise_ValueError(translate("Must be a Group subclass."));
+    }
+    displayio_group_t* group = MP_OBJ_TO_PTR(native_layer);
+    common_hal_displayio_display_show(self, group);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_2(displayio_display_show_obj, displayio_display_obj_show);
+
+//|   .. method:: refresh_soon()
+//|
+//|     Queues up a display refresh that happens in the background.
+//|
+STATIC mp_obj_t displayio_display_obj_refresh_soon(mp_obj_t self_in) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    common_hal_displayio_display_refresh_soon(self);
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_refresh_soon_obj, displayio_display_obj_refresh_soon);
+
+//|   .. method:: wait_for_frame()
+//|
+//|     Waits until the next frame has been transmitted to the display unless the wait count is
+//|     behind the rendered frames. In that case, this will return immediately with the wait count.
+//|
+STATIC mp_obj_t displayio_display_obj_wait_for_frame(mp_obj_t self_in) {
+    displayio_display_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    return MP_OBJ_NEW_SMALL_INT(common_hal_displayio_display_wait_for_frame(self));
+}
+MP_DEFINE_CONST_FUN_OBJ_1(displayio_display_wait_for_frame_obj, displayio_display_obj_wait_for_frame);
+
+
+STATIC const mp_rom_map_elem_t displayio_display_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_show), MP_ROM_PTR(&displayio_display_show_obj) },
+    { MP_ROM_QSTR(MP_QSTR_refresh_soon), MP_ROM_PTR(&displayio_display_refresh_soon_obj) },
+    { MP_ROM_QSTR(MP_QSTR_wait_for_frame), MP_ROM_PTR(&displayio_display_wait_for_frame_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(displayio_display_locals_dict, displayio_display_locals_dict_table);
+
+const mp_obj_type_t displayio_display_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Display,
+    .make_new = displayio_display_make_new,
+    .locals_dict = (mp_obj_dict_t*)&displayio_display_locals_dict,
+};
diff --git a/shared-bindings/displayio/Display.h b/shared-bindings/displayio/Display.h
new file mode 100644
index 000000000..4cec66058
--- /dev/null
+++ b/shared-bindings/displayio/Display.h
@@ -0,0 +1,59 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2017, 2018 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_DISPLAY_H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_DISPLAY_H
+
+#include "common-hal/microcontroller/Pin.h"
+
+#include "shared-module/displayio/Display.h"
+#include "shared-module/displayio/Group.h"
+
+extern const mp_obj_type_t displayio_display_type;
+
+#define DELAY 0x80
+
+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 color_depth,
+    uint8_t set_column_command, uint8_t set_row_command, uint8_t write_ram_command,
+    uint8_t* init_sequence, uint16_t init_sequence_len);
+
+int32_t common_hal_displayio_display_wait_for_frame(displayio_display_obj_t* self);
+
+void common_hal_displayio_display_show(displayio_display_obj_t* self, displayio_group_t* root_group);
+
+void common_hal_displayio_display_refresh_soon(displayio_display_obj_t* self);
+
+void displayio_display_start_region_update(displayio_display_obj_t* self, uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1);
+void displayio_display_finish_region_update(displayio_display_obj_t* self);
+bool displayio_display_frame_queued(displayio_display_obj_t* self);
+
+bool displayio_display_refresh_queued(displayio_display_obj_t* self);
+void displayio_display_finish_refresh(displayio_display_obj_t* self);
+bool displayio_display_send_pixels(displayio_display_obj_t* self, uint32_t* pixels, uint32_t length);
+
+#endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_DISPLAY_H
diff --git a/shared-bindings/displayio/FourWire.c b/shared-bindings/displayio/FourWire.c
index 80aa814df..674d1c900 100644
--- a/shared-bindings/displayio/FourWire.c
+++ b/shared-bindings/displayio/FourWire.c
@@ -3,7 +3,7 @@
  *
  * The MIT License (MIT)
  *
- * Copyright (c) 2018 Scott Shawcroft for Adafruit Industries
+ * Copyright (c) 2018-2019 Scott Shawcroft for Adafruit Industries
  *
  * Permission is hereby granted, free of charge, to any person obtaining a copy
  * of this software and associated documentation files (the "Software"), to deal
@@ -35,6 +35,7 @@
 #include "shared-bindings/displayio/Group.h"
 #include "shared-bindings/microcontroller/Pin.h"
 #include "shared-bindings/util.h"
+#include "shared-module/displayio/__init__.h"
 #include "supervisor/shared/translate.h"
 
 //| .. currentmodule:: displayio
@@ -47,14 +48,44 @@
 //|
 //| .. warning:: This will be changed before 4.0.0. Consider it very experimental.
 //|
-//| .. class:: FourWire(*, clock, data, command, chip_select, width, height, colstart, rowstart,
-//|                     color_depth, set_column_command, set_row_command, write_ram_command)
+//| .. class:: FourWire(spi_bus, *, command, chip_select, reset)
 //|
 //|   Create a FourWire object associated with the given pins.
 //|
 STATIC mp_obj_t displayio_fourwire_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
-    mp_raise_NotImplementedError(translate("displayio is a work in progress"));
-    return mp_const_none;
+    enum { ARG_spi_bus, ARG_command, ARG_chip_select, ARG_reset };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_spi_bus, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_command, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
+        { MP_QSTR_chip_select, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
+        { MP_QSTR_reset, MP_ARG_OBJ | MP_ARG_KW_ONLY, {.u_obj = mp_const_none} },
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    mp_obj_t command = args[ARG_command].u_obj;
+    mp_obj_t chip_select = args[ARG_chip_select].u_obj;
+    mp_obj_t reset = args[ARG_reset].u_obj;
+    if (command == mp_const_none || chip_select == mp_const_none) {
+        mp_raise_ValueError(translate("Command and chip_select required"));
+    }
+
+    displayio_fourwire_obj_t* self;
+    mp_obj_t spi = args[ARG_spi_bus].u_obj;
+    if (board_spi() == spi && primary_display.bus_type == NULL) {
+        self = &primary_display.fourwire_bus;
+        primary_display.bus_type = &displayio_fourwire_type;
+    } else {
+        // TODO(tannewt): Always check pin free. For now we ignore the primary display.
+        assert_pin_free(command);
+        assert_pin_free(chip_select);
+        assert_pin_free(reset);
+        self = m_new_obj(displayio_fourwire_obj_t);
+    }
+
+    common_hal_displayio_fourwire_construct(self,
+        MP_OBJ_TO_PTR(spi), command, chip_select, reset);
+    return self;
 }
 
 
@@ -68,50 +99,8 @@ STATIC mp_obj_t displayio_fourwire_obj_send(size_t n_args, const mp_obj_t *pos_a
 }
 MP_DEFINE_CONST_FUN_OBJ_KW(displayio_fourwire_send_obj, 1, displayio_fourwire_obj_send);
 
-//|   .. method:: show(group)
-//|
-//|     Switches do displaying the given group of elements.
-//|
-STATIC mp_obj_t displayio_fourwire_obj_show(mp_obj_t self_in, mp_obj_t group_in) {
-    displayio_fourwire_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    mp_obj_t native_layer = mp_instance_cast_to_native_base(group_in, &displayio_group_type);
-    if (native_layer == MP_OBJ_NULL) {
-        mp_raise_ValueError(translate("Must be a Group subclass."));
-    }
-    displayio_group_t* group = MP_OBJ_TO_PTR(native_layer);
-    common_hal_displayio_fourwire_show(self, group);
-    return mp_const_none;
-}
-MP_DEFINE_CONST_FUN_OBJ_2(displayio_fourwire_show_obj, displayio_fourwire_obj_show);
-
-//|   .. method:: refresh_soon()
-//|
-//|     Queues up a display refresh that happens in the background.
-//|
-STATIC mp_obj_t displayio_fourwire_obj_refresh_soon(mp_obj_t self_in) {
-    displayio_fourwire_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    common_hal_displayio_fourwire_refresh_soon(self);
-    return mp_const_none;
-}
-MP_DEFINE_CONST_FUN_OBJ_1(displayio_fourwire_refresh_soon_obj, displayio_fourwire_obj_refresh_soon);
-
-//|   .. method:: wait_for_frame()
-//|
-//|     Waits until the next frame has been transmitted to the display unless the wait count is
-//|     behind the rendered frames. In that case, this will return immediately with the wait count.
-//|
-STATIC mp_obj_t displayio_fourwire_obj_wait_for_frame(mp_obj_t self_in) {
-    displayio_fourwire_obj_t *self = MP_OBJ_TO_PTR(self_in);
-    return MP_OBJ_NEW_SMALL_INT(common_hal_displayio_fourwire_wait_for_frame(self));
-}
-MP_DEFINE_CONST_FUN_OBJ_1(displayio_fourwire_wait_for_frame_obj, displayio_fourwire_obj_wait_for_frame);
-
-
 STATIC const mp_rom_map_elem_t displayio_fourwire_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&displayio_fourwire_send_obj) },
-    { MP_ROM_QSTR(MP_QSTR_show), MP_ROM_PTR(&displayio_fourwire_show_obj) },
-    { MP_ROM_QSTR(MP_QSTR_refresh_soon), MP_ROM_PTR(&displayio_fourwire_refresh_soon_obj) },
-    { MP_ROM_QSTR(MP_QSTR_wait_for_frame), MP_ROM_PTR(&displayio_fourwire_wait_for_frame_obj) },
 };
 STATIC MP_DEFINE_CONST_DICT(displayio_fourwire_locals_dict, displayio_fourwire_locals_dict_table);
 
diff --git a/shared-bindings/displayio/FourWire.h b/shared-bindings/displayio/FourWire.h
index fc51f558d..a9e1bf566 100644
--- a/shared-bindings/displayio/FourWire.h
+++ b/shared-bindings/displayio/FourWire.h
@@ -31,35 +31,18 @@
 #include "common-hal/microcontroller/Pin.h"
 
 #include "shared-module/displayio/Group.h"
+#include "supervisor/shared/board_busses.h"
 
 extern const mp_obj_type_t displayio_fourwire_type;
 
-// TODO(tannewt): Split this apart into FourWire and a Display object because the dimensions and
-// commands are also used for the parallel buses.
 void common_hal_displayio_fourwire_construct(displayio_fourwire_obj_t* self,
-    const mcu_pin_obj_t* clock, const mcu_pin_obj_t* data, const mcu_pin_obj_t* command,
-    const mcu_pin_obj_t* chip_select, const mcu_pin_obj_t* reset, uint16_t width, uint16_t height,
-    int16_t colstart, int16_t rowstart, uint16_t color_depth,
-    uint8_t set_column_command, uint8_t set_row_command, uint8_t write_ram_command);
+    busio_spi_obj_t* spi, const mcu_pin_obj_t* command,
+    const mcu_pin_obj_t* chip_select, const mcu_pin_obj_t* reset);
 
-int32_t common_hal_displayio_fourwire_wait_for_frame(displayio_fourwire_obj_t* self);
+bool common_hal_displayio_fourwire_begin_transaction(mp_obj_t self);
 
-bool common_hal_displayio_fourwire_begin_transaction(displayio_fourwire_obj_t* self);
+void common_hal_displayio_fourwire_send(mp_obj_t self, bool command, uint8_t *data, uint32_t data_length);
 
-void common_hal_displayio_fourwire_send(displayio_fourwire_obj_t* self, bool command, uint8_t *data, uint32_t data_length);
-
-void common_hal_displayio_fourwire_end_transaction(displayio_fourwire_obj_t* self);
-
-void common_hal_displayio_fourwire_show(displayio_fourwire_obj_t* self, displayio_group_t* root_group);
-
-void common_hal_displayio_fourwire_refresh_soon(displayio_fourwire_obj_t* self);
-
-void displayio_fourwire_start_region_update(displayio_fourwire_obj_t* self, uint16_t x0, uint16_t y0, uint16_t x1, uint16_t y1);
-void displayio_fourwire_finish_region_update(displayio_fourwire_obj_t* self);
-bool displayio_fourwire_frame_queued(displayio_fourwire_obj_t* self);
-
-bool displayio_fourwire_refresh_queued(displayio_fourwire_obj_t* self);
-void displayio_fourwire_finish_refresh(displayio_fourwire_obj_t* self);
-bool displayio_fourwire_send_pixels(displayio_fourwire_obj_t* self, uint32_t* pixels, uint32_t length);
+void common_hal_displayio_fourwire_end_transaction(mp_obj_t self);
 
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_FOURWIRE_H
diff --git a/shared-bindings/displayio/ParallelBus.c b/shared-bindings/displayio/ParallelBus.c
new file mode 100644
index 000000000..dddb4ce8a
--- /dev/null
+++ b/shared-bindings/displayio/ParallelBus.c
@@ -0,0 +1,79 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "shared-bindings/displayio/ParallelBus.h"
+
+#include <stdint.h>
+
+#include "lib/utils/context_manager_helpers.h"
+#include "py/binary.h"
+#include "py/objproperty.h"
+#include "py/runtime.h"
+#include "shared-bindings/microcontroller/Pin.h"
+#include "shared-bindings/util.h"
+#include "supervisor/shared/translate.h"
+
+//| .. currentmodule:: displayio
+//|
+//| :class:`ParallelBus` -- Manage updating a display over SPI four wire protocol
+//| ==========================================================================
+//|
+//| Manage updating a display over SPI four wire protocol in the background while Python code runs.
+//| It doesn't handle display initialization.
+//|
+//| .. warning:: This will be changed before 4.0.0. Consider it very experimental.
+//|
+//| .. class:: ParallelBus(*, data0, command, chip_select, reset, write, bus_width=8)
+//|
+//|   Create a ParallelBus object associated with the given pins.
+//|
+STATIC mp_obj_t displayio_parallelbus_make_new(const mp_obj_type_t *type, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    mp_raise_NotImplementedError(translate("displayio is a work in progress"));
+    return mp_const_none;
+}
+
+
+//|   .. method:: send(command, data)
+//|
+//|
+STATIC mp_obj_t displayio_parallelbus_obj_send(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    mp_raise_NotImplementedError(translate("displayio is a work in progress"));
+
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_KW(displayio_parallelbus_send_obj, 1, displayio_parallelbus_obj_send);
+
+STATIC const mp_rom_map_elem_t displayio_parallelbus_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_send), MP_ROM_PTR(&displayio_parallelbus_send_obj) },
+};
+STATIC MP_DEFINE_CONST_DICT(displayio_parallelbus_locals_dict, displayio_parallelbus_locals_dict_table);
+
+const mp_obj_type_t displayio_parallelbus_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_ParallelBus,
+    .make_new = displayio_parallelbus_make_new,
+    .locals_dict = (mp_obj_dict_t*)&displayio_parallelbus_locals_dict,
+};
diff --git a/shared-bindings/displayio/ParallelBus.h b/shared-bindings/displayio/ParallelBus.h
new file mode 100644
index 000000000..f1d1656b1
--- /dev/null
+++ b/shared-bindings/displayio/ParallelBus.h
@@ -0,0 +1,47 @@
+/*
+ * This file is part of the Micro Python project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2019 Scott Shawcroft for Adafruit Industries
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_PARALLELBUS_H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_PARALLELBUS_H
+
+#include "common-hal/displayio/ParallelBus.h"
+#include "common-hal/microcontroller/Pin.h"
+
+#include "shared-module/displayio/Group.h"
+
+extern const mp_obj_type_t displayio_parallelbus_type;
+
+void common_hal_displayio_parallelbus_construct(displayio_parallelbus_obj_t* self,
+    const mcu_pin_obj_t* data0, const mcu_pin_obj_t* command,
+    const mcu_pin_obj_t* chip_select, const mcu_pin_obj_t* reset, const mcu_pin_obj_t* write);
+
+bool common_hal_displayio_parallelbus_begin_transaction(mp_obj_t self);
+
+void common_hal_displayio_parallelbus_send(mp_obj_t self, bool command, uint8_t *data, uint32_t data_length);
+
+void common_hal_displayio_parallelbus_end_transaction(mp_obj_t self);
+
+#endif // MICROPY_INCLUDED_SHARED_BINDINGS_DISPLAYBUSIO_PARALLELBUS_H