From 674a4bbe274b677f2ae1dc4ac02e05458b71e851 Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 1/7] Add display backlight control.

---
 drivers/st7701/st7701.cpp   | 21 ++++++---------------
 drivers/st7701/st7701.hpp   |  1 +
 modules/c/presto/presto.c   |  2 ++
 modules/c/presto/presto.cpp | 12 ++++++++++++
 modules/c/presto/presto.h   |  3 ++-
 5 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/drivers/st7701/st7701.cpp b/drivers/st7701/st7701.cpp
index ee57551..81df60a 100644
--- a/drivers/st7701/st7701.cpp
+++ b/drivers/st7701/st7701.cpp
@@ -349,17 +349,11 @@ void ST7701::init_framebuffer() {
     // if a backlight pin is provided then set it up for
     // pwm control
     if(lcd_bl != PIN_UNUSED) {
-      #if 0
       pwm_config cfg = pwm_get_default_config();
-      pwm_set_wrap(pwm_gpio_to_slice_num(lcd_bl), 65535);
+      pwm_config_set_wrap(&cfg, BACKLIGHT_PWM_TOP);
       pwm_init(pwm_gpio_to_slice_num(lcd_bl), &cfg, true);
       gpio_set_function(lcd_bl, GPIO_FUNC_PWM);
       set_backlight(0); // Turn backlight off initially to avoid nasty surprises
-      #else
-      gpio_init(lcd_bl);
-      gpio_set_dir(lcd_bl, GPIO_OUT);
-      gpio_put(lcd_bl, 0);
-      #endif
     }
 
     command(reg::SWRESET);
@@ -430,11 +424,7 @@ void ST7701::init_framebuffer() {
     if(lcd_bl != PIN_UNUSED) {
       //update(); // Send the new buffer to the display to clear any previous content
       sleep_ms(50); // Wait for the update to apply
-      #if 0
       set_backlight(255); // Turn backlight on now surprises have passed
-      #else
-      gpio_put(lcd_bl, 1);
-      #endif
     }
   }
 
@@ -550,10 +540,11 @@ void ST7701::init_framebuffer() {
   }
 
   void ST7701::set_backlight(uint8_t brightness) {
-    // gamma correct the provided 0-255 brightness value onto a
-    // 0-65535 range for the pwm counter
-    float gamma = 2.8;
-    uint16_t value = (uint16_t)(pow((float)(brightness) / 255.0f, gamma) * 65535.0f + 0.5f);
+    // At least on my hardware this gives reasonable control over the possible range of backlight brightness
+    uint16_t value;
+    if (brightness == 0) value = 0;
+    else if (brightness == 255) value = BACKLIGHT_PWM_TOP;
+    else value = 181 + (brightness * brightness) / 85;
     pwm_set_gpio_level(lcd_bl, value);
   }
 
diff --git a/drivers/st7701/st7701.hpp b/drivers/st7701/st7701.hpp
index d1218b4..622a8ef 100644
--- a/drivers/st7701/st7701.hpp
+++ b/drivers/st7701/st7701.hpp
@@ -47,6 +47,7 @@ namespace pimoroni {
     uint lcd_dot_clk = 22;
 
     static const uint32_t SPI_BAUD = 8'000'000;
+    static const uint32_t BACKLIGHT_PWM_TOP = 6200;
 
   public:
     // Parallel init
diff --git a/modules/c/presto/presto.c b/modules/c/presto/presto.c
index a4bab70..7a8511d 100644
--- a/modules/c/presto/presto.c
+++ b/modules/c/presto/presto.c
@@ -5,12 +5,14 @@
 
 MP_DEFINE_CONST_FUN_OBJ_1(Presto___del___obj, Presto___del__);
 MP_DEFINE_CONST_FUN_OBJ_2(Presto_update_obj, Presto_update);
+MP_DEFINE_CONST_FUN_OBJ_2(Presto_set_backlight_obj, Presto_set_backlight);
 
 /***** Binding of Methods *****/
 
 static const mp_rom_map_elem_t Presto_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&Presto___del___obj) },
     { MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&Presto_update_obj) },
+    { MP_ROM_QSTR(MP_QSTR_set_backlight), MP_ROM_PTR(&Presto_set_backlight_obj) },
 
     { MP_ROM_QSTR(MP_QSTR_WIDTH), MP_ROM_INT(WIDTH) },
     { MP_ROM_QSTR(MP_QSTR_HEIGHT), MP_ROM_INT(HEIGHT) },
diff --git a/modules/c/presto/presto.cpp b/modules/c/presto/presto.cpp
index fc38d10..b3cd1cb 100644
--- a/modules/c/presto/presto.cpp
+++ b/modules/c/presto/presto.cpp
@@ -159,6 +159,18 @@ extern mp_obj_t Presto_update(mp_obj_t self_in, mp_obj_t graphics_in) {
     return mp_const_none;
 }
 
+mp_obj_t Presto_set_backlight(mp_obj_t self_in, mp_obj_t brightness) {
+    _Presto_obj_t *self = MP_OBJ_TO_PTR2(self_in, _Presto_obj_t);
+
+    float b = mp_obj_get_float(brightness);
+
+    if(b < 0 || b > 1.0f) mp_raise_ValueError("brightness out of range. Expected 0.0 to 1.0");
+
+    self->presto->set_backlight((uint8_t)(b * 255.0f));
+
+    return mp_const_none;
+}
+
 mp_obj_t Presto___del__(mp_obj_t self_in) {
     (void)self_in;
     //_Presto_obj_t *self = MP_OBJ_TO_PTR2(self_in, _Presto_obj_t);
diff --git a/modules/c/presto/presto.h b/modules/c/presto/presto.h
index b153651..95127ec 100644
--- a/modules/c/presto/presto.h
+++ b/modules/c/presto/presto.h
@@ -2,7 +2,7 @@
 #include "py/runtime.h"
 
 /***** Constants *****/
-static const uint BACKLIGHT = 38;
+static const uint BACKLIGHT = 45;
 
 static const int WIDTH = 240;
 static const int HEIGHT = 240;
@@ -19,4 +19,5 @@ extern const mp_obj_type_t Presto_type;
 extern mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
 extern mp_obj_t Presto_update(mp_obj_t self_in, mp_obj_t graphics_in);
 extern mp_int_t Presto_get_framebuffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags);
+extern mp_obj_t Presto_set_backlight(mp_obj_t self_in, mp_obj_t brightness);
 extern mp_obj_t Presto___del__(mp_obj_t self_in);
\ No newline at end of file

From 43a660626a5fb1fa6b06203e4b39beb6b15f245a Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 2/7] MicroPython: Full res option.

---
 modules/c/presto/presto.c   |  6 ++++--
 modules/c/presto/presto.cpp | 28 +++++++++++++++++++---------
 modules/c/presto/presto.h   |  4 ++--
 presto/mpconfigboard.h      |  1 +
 4 files changed, 26 insertions(+), 13 deletions(-)

diff --git a/modules/c/presto/presto.c b/modules/c/presto/presto.c
index 7a8511d..8cfbc3b 100644
--- a/modules/c/presto/presto.c
+++ b/modules/c/presto/presto.c
@@ -14,8 +14,10 @@ static const mp_rom_map_elem_t Presto_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&Presto_update_obj) },
     { MP_ROM_QSTR(MP_QSTR_set_backlight), MP_ROM_PTR(&Presto_set_backlight_obj) },
 
-    { MP_ROM_QSTR(MP_QSTR_WIDTH), MP_ROM_INT(WIDTH) },
-    { MP_ROM_QSTR(MP_QSTR_HEIGHT), MP_ROM_INT(HEIGHT) },
+    { MP_ROM_QSTR(MP_QSTR_WIDTH), MP_ROM_INT(WIDTH/2) },
+    { MP_ROM_QSTR(MP_QSTR_HEIGHT), MP_ROM_INT(HEIGHT/2) },
+    { MP_ROM_QSTR(MP_QSTR_FULL_WIDTH), MP_ROM_INT(WIDTH) },
+    { MP_ROM_QSTR(MP_QSTR_FULL_HEIGHT), MP_ROM_INT(HEIGHT) },
 };
 
 static MP_DEFINE_CONST_DICT(Presto_locals_dict, Presto_locals_dict_table);
diff --git a/modules/c/presto/presto.cpp b/modules/c/presto/presto.cpp
index b3cd1cb..74e2dc3 100644
--- a/modules/c/presto/presto.cpp
+++ b/modules/c/presto/presto.cpp
@@ -20,8 +20,7 @@ extern "C" {
 
 // MicroPython's GC heap will automatically resize, so we should just
 // statically allocate these in C++ to avoid fragmentation.
-__attribute__((section(".uninitialized_data"))) static uint16_t presto_buffer_a[WIDTH * HEIGHT] = {0};
-__attribute__((section(".uninitialized_data"))) static uint16_t presto_buffer_b[WIDTH * HEIGHT] = {0};
+__attribute__((section(".uninitialized_data"))) static uint16_t presto_buffer[WIDTH * HEIGHT] = {0};
 
 void __printf_debug_flush() {
     for(auto i = 0u; i < 10; i++) {
@@ -47,6 +46,8 @@ typedef struct _Presto_obj_t {
     ST7701* presto;
     uint16_t* next_fb;
     uint16_t* curr_fb;
+    uint16_t width;
+    uint16_t height;
 } _Presto_obj_t;
 
 typedef struct _ModPicoGraphics_obj_t {
@@ -79,10 +80,9 @@ static uint32_t core1_stack[stack_size] = {0};
 mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
     _Presto_obj_t *self = nullptr;
 
-    enum { ARG_pio, ARG_sm, ARG_pins, ARG_common_pin, ARG_direction, ARG_counts_per_rev, ARG_count_microsteps, ARG_freq_divider };
+    enum { ARG_full_res };
     static const mp_arg_t allowed_args[] = {
-        { MP_QSTR_pio, MP_ARG_INT },
-        { MP_QSTR_sm, MP_ARG_INT }
+        { MP_QSTR_full_res, MP_ARG_BOOL, {.u_bool = false} }
     };
 
     // Parse args.
@@ -93,11 +93,21 @@ mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw,
     self = mp_obj_malloc_with_finaliser(_Presto_obj_t, &Presto_type);
 
     presto_debug("set fb pointers\n");
-    self->curr_fb = presto_buffer_a; //(uint16_t*)0x11000000;
-    self->next_fb = presto_buffer_b; //(uint16_t*)0x11080000;
+    self->curr_fb = presto_buffer;
+    self->next_fb = presto_buffer;
+
+    if (!args[ARG_full_res].u_bool) {
+        self->width = WIDTH / 2;
+        self->height = HEIGHT / 2;
+        self->next_fb += (WIDTH * HEIGHT) / 4;
+    }
+    else {
+        self->width = WIDTH;
+        self->height = HEIGHT;
+    }
 
     presto_debug("m_new_class(ST7701...\n");
-    ST7701 *presto = m_new_class(ST7701, WIDTH, HEIGHT, ROTATE_0,
+    ST7701 *presto = m_new_class(ST7701, self->width, self->height, ROTATE_0,
         SPIPins{spi1, LCD_CS, LCD_CLK, LCD_DAT, PIN_UNUSED, LCD_DC, BACKLIGHT},
         self->next_fb,
         LCD_D0);
@@ -141,7 +151,7 @@ mp_int_t Presto_get_framebuffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_
     _Presto_obj_t *self = MP_OBJ_TO_PTR2(self_in, _Presto_obj_t);
     (void)flags;
     bufinfo->buf = self->curr_fb;
-    bufinfo->len = WIDTH * HEIGHT * 2;
+    bufinfo->len = self->width * self->height * 2;
     bufinfo->typecode = 'B';
     return 0;
 }
diff --git a/modules/c/presto/presto.h b/modules/c/presto/presto.h
index 95127ec..3c72a98 100644
--- a/modules/c/presto/presto.h
+++ b/modules/c/presto/presto.h
@@ -4,8 +4,8 @@
 /***** Constants *****/
 static const uint BACKLIGHT = 45;
 
-static const int WIDTH = 240;
-static const int HEIGHT = 240;
+static const int WIDTH = 480;
+static const int HEIGHT = 480;
 static const uint LCD_CLK = 26;
 static const uint LCD_CS = 28;
 static const uint LCD_DAT = 27;
diff --git a/presto/mpconfigboard.h b/presto/mpconfigboard.h
index ea5ee1e..c7c5f25 100644
--- a/presto/mpconfigboard.h
+++ b/presto/mpconfigboard.h
@@ -33,6 +33,7 @@ int mp_hal_is_pin_reserved(int n);
 #define MICROPY_HW_ENABLE_PSRAM                 (1)
 
 #define MICROPY_PY_THREAD                       (0)
+#define MICROPY_GC_SPLIT_HEAP                   (0)
 
 // TODO: Remove when https://github.com/micropython/micropython/pull/15655 is merged
 #define core1_entry                             (NULL)
\ No newline at end of file

From b896b4ef08ea3bf1d040a5f01db019e84ff33ff3 Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 3/7] Examples: Full res vector clock example.

---
 examples/vector_clock_full.py | 138 ++++++++++++++++++++++++++++++++++
 1 file changed, 138 insertions(+)
 create mode 100644 examples/vector_clock_full.py

diff --git a/examples/vector_clock_full.py b/examples/vector_clock_full.py
new file mode 100644
index 0000000..7684ca5
--- /dev/null
+++ b/examples/vector_clock_full.py
@@ -0,0 +1,138 @@
+import presto
+
+import time
+import gc
+
+from picographics import PicoGraphics, DISPLAY_PRESTO_FULL_RES
+from picovector import PicoVector, Polygon, RegularPolygon, Rectangle, ANTIALIAS_X4, ANTIALIAS_X16
+
+machine.freq(264000000)
+
+presto = presto.Presto(full_res=True)
+
+display = PicoGraphics(DISPLAY_PRESTO_FULL_RES)
+
+vector = PicoVector(display)
+vector.set_antialiasing(ANTIALIAS_X4)
+
+RED = display.create_pen(200, 0, 0)
+BLACK = display.create_pen(0, 0, 0)
+GREY = display.create_pen(200, 200, 200)
+WHITE = display.create_pen(255, 255, 255)
+
+"""
+# Redefine colours for a Blue clock
+RED = display.create_pen(200, 0, 0)
+BLACK = display.create_pen(135, 159, 169)
+GREY = display.create_pen(10, 40, 50)
+WHITE = display.create_pen(14, 60, 76)
+"""
+
+WIDTH, HEIGHT = display.get_bounds()
+
+hub = RegularPolygon(int(WIDTH / 2), int(HEIGHT / 2), 24, 5)
+
+face = RegularPolygon(int(WIDTH / 2), int(HEIGHT / 2), 48, int(HEIGHT / 2))
+
+print(time.localtime())
+
+last_second = None
+
+def fade_in():
+    for j in range(101):
+        presto.set_backlight(j*0.01)
+        time.sleep_us(700)
+        
+def fade_out():
+    for j in range(101):
+        presto.set_backlight(1 - j*0.01)
+        time.sleep_us(700)
+
+while True:
+    t_start = time.ticks_ms()
+    year, month, day, hour, minute, second, _, _ = time.localtime()
+
+    if last_second == second:
+        time.sleep_ms(10)
+        continue
+
+    last_second = second
+
+    fade_out()
+
+    display.set_pen(0)
+    display.clear()
+
+    display.set_pen(BLACK)
+    display.circle(int(WIDTH / 2), int(HEIGHT / 2), int(HEIGHT / 2))
+    display.set_pen(WHITE)
+    display.circle(int(WIDTH / 2), int(HEIGHT / 2), int(HEIGHT / 2) - 4)
+
+    display.set_pen(GREY)
+
+    for a in range(60):
+        tick_mark = Rectangle(int(WIDTH / 2) - 3, 10, 6, int(HEIGHT / 48))
+        vector.rotate(tick_mark, 360 / 60.0 * a, int(WIDTH / 2), int(HEIGHT / 2))
+        vector.translate(tick_mark, 0, 2)
+        vector.draw(tick_mark)
+
+    for a in range(12):
+        hour_mark = Rectangle(int(WIDTH / 2) - 5, 10, 10, int(HEIGHT / 10))
+        vector.rotate(hour_mark, 360 / 12.0 * a, int(WIDTH / 2), int(HEIGHT / 2))
+        vector.translate(hour_mark, 0, 2)
+        vector.draw(hour_mark)
+
+    angle_second = second * 6
+    second_hand_length = int(HEIGHT / 2) - int(HEIGHT / 8)
+    second_hand = Polygon((-2, -second_hand_length), (-2, int(HEIGHT / 8)), (2, int(HEIGHT / 8)), (2, -second_hand_length))
+    vector.rotate(second_hand, angle_second, 0, 0)
+    vector.translate(second_hand, int(WIDTH / 2), int(HEIGHT / 2) + 5)
+
+    angle_minute = minute * 6
+    angle_minute += second / 10.0
+    minute_hand_length = int(HEIGHT / 2) - int(HEIGHT / 24)
+    minute_hand = Polygon((-5, -minute_hand_length), (-10, int(HEIGHT / 16)), (10, int(HEIGHT / 16)), (5, -minute_hand_length))
+    vector.rotate(minute_hand, angle_minute, 0, 0)
+    vector.translate(minute_hand, int(WIDTH / 2), int(HEIGHT / 2) + 5)
+
+    angle_hour = (hour % 12) * 30
+    angle_hour += minute / 2
+    hour_hand_length = int(HEIGHT / 2) - int(HEIGHT / 8)
+    hour_hand = Polygon((-5, -hour_hand_length), (-10, int(HEIGHT / 16)), (10, int(HEIGHT / 16)), (5, -hour_hand_length))
+    vector.rotate(hour_hand, angle_hour, 0, 0)
+    vector.translate(hour_hand, int(WIDTH / 2), int(HEIGHT / 2) + 5)
+
+    display.set_pen(GREY)
+
+    vector.draw(minute_hand)
+    vector.draw(hour_hand)
+    vector.draw(second_hand)
+
+    display.set_pen(BLACK)
+
+    for a in range(60):
+        tick_mark = Rectangle(int(WIDTH / 2) - 3, 10, 6, int(HEIGHT / 48))
+        vector.rotate(tick_mark, 360 / 60.0 * a, int(WIDTH / 2), int(HEIGHT / 2))
+        vector.draw(tick_mark)
+
+    for a in range(12):
+        hour_mark = Rectangle(int(WIDTH / 2) - 5, 10, 10, int(HEIGHT / 10))
+        vector.rotate(hour_mark, 360 / 12.0 * a, int(WIDTH / 2), int(HEIGHT / 2))
+        vector.draw(hour_mark)
+
+    vector.translate(minute_hand, 0, -5)
+    vector.translate(hour_hand, 0, -5)
+    vector.draw(minute_hand)
+    vector.draw(hour_hand)
+
+    display.set_pen(RED)
+    vector.translate(second_hand, 0, -5)
+    vector.draw(second_hand)
+    vector.draw(hub)
+
+    presto.update(display)
+    fade_in()
+    gc.collect()
+
+    t_end = time.ticks_ms()
+    print(f"Took {t_end - t_start}ms")

From 2d5e899fde914cd4a7063c52be386677e325cc3a Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 4/7] ST7701: Single program for full and half res.

---
 drivers/st7701/st7701.cpp          | 32 +++++++++++-------------------
 drivers/st7701/st7701_parallel.pio | 16 +--------------
 2 files changed, 13 insertions(+), 35 deletions(-)

diff --git a/drivers/st7701/st7701.cpp b/drivers/st7701/st7701.cpp
index 81df60a..de68256 100644
--- a/drivers/st7701/st7701.cpp
+++ b/drivers/st7701/st7701.cpp
@@ -224,13 +224,7 @@ void ST7701::init_framebuffer() {
       st_pio = pio1;
       parallel_sm = pio_claim_unused_sm(st_pio, true);
 
-      if      (width == 480) parallel_offset = pio_add_program(st_pio, &st7701_parallel_program);
-      else if (width == 240) parallel_offset = pio_add_program(st_pio, &st7701_parallel_double_program);
-      else {
-        printf("Unsupported width\n");
-        return;
-      }
-
+      parallel_offset = pio_add_program(st_pio, &st7701_parallel_program);
       if (height == 240) row_shift = 1;
 
       timing_sm = pio_claim_unused_sm(st_pio, true);
@@ -268,9 +262,7 @@ void ST7701::init_framebuffer() {
       pio_sm_set_consecutive_pindirs(st_pio, parallel_sm, d0, 16, true);
       pio_sm_set_consecutive_pindirs(st_pio, parallel_sm, hsync, 4, true);
 
-      pio_sm_config c;
-      if (width == 480) c = st7701_parallel_program_get_default_config(parallel_offset);
-      else              c = st7701_parallel_double_program_get_default_config(parallel_offset);
+      pio_sm_config c = st7701_parallel_program_get_default_config(parallel_offset);
 
       sm_config_set_out_pins(&c, d0, 16);
       sm_config_set_sideset_pins(&c, lcd_de);
@@ -279,18 +271,18 @@ void ST7701::init_framebuffer() {
       sm_config_set_in_shift(&c, false, false, 32);
       
       // Determine clock divider
-      uint32_t max_pio_clk;
-      if ((intptr_t)framebuffer >= 0x14000000 || width <= 240) {
-        // Frame buffer in internal RAM or pixel doubling, go as fast as possible
-        max_pio_clk = 34 * MHZ;
+      uint32_t max_pio_clk = 34 * MHZ;
+      const uint32_t sys_clk_hz = clock_get_hz(clk_sys);
+      uint32_t clk_div = (sys_clk_hz + max_pio_clk - 1) / max_pio_clk;
+      if (width == 480) {
+        // Parallel output SM must run at double the rate of the timing SM for full res
+        if (clk_div & 1) clk_div += 1;
+        sm_config_set_clkdiv(&c, clk_div >> 1);
       }
-      else {
-        // Frame buffer in PSRAM and not pixel doubling, slow down a bit
-        max_pio_clk = 25 * MHZ;
+      else
+      {
+        sm_config_set_clkdiv(&c, clk_div);
       }
-      const uint32_t sys_clk_hz = clock_get_hz(clk_sys);
-      const uint32_t clk_div = (sys_clk_hz + max_pio_clk - 1) / max_pio_clk;
-      sm_config_set_clkdiv(&c, clk_div);
       
       pio_sm_init(st_pio, parallel_sm, parallel_offset, &c);
       pio_sm_exec(st_pio, parallel_sm, pio_encode_out(pio_y, 32));
diff --git a/drivers/st7701/st7701_parallel.pio b/drivers/st7701/st7701_parallel.pio
index 2836f72..3b1f510 100644
--- a/drivers/st7701/st7701_parallel.pio
+++ b/drivers/st7701/st7701_parallel.pio
@@ -1,22 +1,8 @@
-; Output 16 bit parallel RGB565 data every clock
+; Output 16 bit parallel, bit reversed, RGB565 data every 4th clock
 ; Wait for irq 4 from the timing SM between each row
 ; Side-set is data enable
 
 .program st7701_parallel
-.side_set 1
-
-  mov pins, null side 0
-  wait 1 irq 4   side 0
-.wrap_target
-  out isr,  32    side 1
-  mov pins, ::isr side 1
-  in null, 16     side 1
-  mov pins, ::isr side 1  
-.wrap
-
-; Output 16 bit parallel RGB565 data every other clock
-
-.program st7701_parallel_double
 .side_set 1
 
 .wrap_target

From 4c359639df585141fb9bf2e10a6e5562cfb4d86e Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 5/7] PicoGraphics style update instead of buffer flip.

---
 drivers/st7701/st7701.cpp   | 46 ++++++++++++-------------------------
 drivers/st7701/st7701.hpp   |  2 +-
 modules/c/presto/presto.c   |  2 ++
 modules/c/presto/presto.cpp | 42 +++++++++++++++++++++++++--------
 modules/c/presto/presto.h   |  1 +
 5 files changed, 51 insertions(+), 42 deletions(-)

diff --git a/drivers/st7701/st7701.cpp b/drivers/st7701/st7701.cpp
index de68256..1b26cb8 100644
--- a/drivers/st7701/st7701.cpp
+++ b/drivers/st7701/st7701.cpp
@@ -171,8 +171,6 @@ void ST7701::start_frame_xfer()
     if (next_framebuffer) {
         framebuffer = next_framebuffer;
         next_framebuffer = nullptr;
-
-        init_framebuffer();
     }
 
     next_line_addr = 0;
@@ -192,19 +190,6 @@ void ST7701::start_frame_xfer()
     __sev();
 }
 
-void ST7701::init_framebuffer() {
-    // If framebuffer not in cache XIP memory, do nothing.
-    if ((intptr_t)framebuffer >= 0x14000000) return;
-
-    // Flush the frame buffer from cache
-    uint8_t* framebuffer_maintenance = (uint8_t*)framebuffer + 0x8000000;
-    for (int i = 3; i < width*height << 1; i += 8)
-        framebuffer_maintenance[i] = 0; // Clean
-
-    // Switch to uncached reads
-    framebuffer += 0x2000000;
-}
-
   ST7701::ST7701(uint16_t width, uint16_t height, Rotation rotation, SPIPins control_pins, uint16_t* framebuffer,
       uint d0, uint hsync, uint vsync, uint lcd_de, uint lcd_dot_clk) :
             DisplayDriver(width, height, rotation),
@@ -219,8 +204,6 @@ void ST7701::init_framebuffer() {
   void ST7701::init() {
       irq_handler_t current = nullptr;
   
-      init_framebuffer();
-
       st_pio = pio1;
       parallel_sm = pio_claim_unused_sm(st_pio, true);
 
@@ -511,23 +494,24 @@ void ST7701::init_framebuffer() {
   }
   
   void ST7701::update(PicoGraphics *graphics) {
-    //uint8_t cmd = reg::RAMWR;
-
-    // TODO: Where's my buffer at? Where's my buffer at?
-    // I left it out back in the PSRAM chip, y'all
-    // And now I cannot find it even though it's 60k tall
-
-    if(graphics->pen_type == PicoGraphics::PEN_RGB565) { // Display buffer is screen native
-      // command(cmd, width * height * sizeof(uint16_t), (const char*)graphics->frame_buffer);
+    if(graphics->pen_type == PicoGraphics::PEN_RGB565 && graphics->layers == 1) { // Display buffer is screen native
+      memcpy(framebuffer, graphics->frame_buffer, width * height * sizeof(uint16_t));
     } else {
-      /*graphics->frame_convert(PicoGraphics::PEN_RGB565, [this](void *data, size_t length) {
+      uint8_t* frame_ptr = (uint8_t*)framebuffer;
+      graphics->frame_convert(PicoGraphics::PEN_RGB565, [this, &frame_ptr](void *data, size_t length) {
         if (length > 0) {
-          write_blocking_dma((const uint8_t*)data, length);
-        }
-        else {
-          dma_channel_wait_for_finish_blocking(st_dma);
+          memcpy(frame_ptr, data, length);
+          frame_ptr += length;
         }
-      });*/
+      });
+    }
+  }
+
+  void ST7701::partial_update(PicoGraphics *graphics, Rect region) {
+    if(graphics->pen_type == PicoGraphics::PEN_RGB565 && graphics->layers == 1) { // Display buffer is screen native
+      for (int y = region.y; y < region.y + region.h; ++y) {
+        memcpy(&framebuffer[y * width + region.x], (uint16_t*)graphics->frame_buffer + y * width + region.x, region.w * sizeof(uint16_t));
+      }
     }
   }
 
diff --git a/drivers/st7701/st7701.hpp b/drivers/st7701/st7701.hpp
index 622a8ef..531b340 100644
--- a/drivers/st7701/st7701.hpp
+++ b/drivers/st7701/st7701.hpp
@@ -57,6 +57,7 @@ namespace pimoroni {
     void init();
     void cleanup() override;
     void update(PicoGraphics *graphics) override;
+    void partial_update(PicoGraphics *display, Rect region) override;
     void set_backlight(uint8_t brightness) override;
 
     void set_framebuffer(uint16_t* next_fb) {
@@ -78,7 +79,6 @@ namespace pimoroni {
 
     void start_line_xfer();
     void start_frame_xfer();
-    void init_framebuffer();
 
     // Timing status
     uint16_t timing_row = 0;
diff --git a/modules/c/presto/presto.c b/modules/c/presto/presto.c
index 8cfbc3b..ec63546 100644
--- a/modules/c/presto/presto.c
+++ b/modules/c/presto/presto.c
@@ -5,6 +5,7 @@
 
 MP_DEFINE_CONST_FUN_OBJ_1(Presto___del___obj, Presto___del__);
 MP_DEFINE_CONST_FUN_OBJ_2(Presto_update_obj, Presto_update);
+MP_DEFINE_CONST_FUN_OBJ_KW(Presto_partial_update_obj, 5, Presto_partial_update);
 MP_DEFINE_CONST_FUN_OBJ_2(Presto_set_backlight_obj, Presto_set_backlight);
 
 /***** Binding of Methods *****/
@@ -12,6 +13,7 @@ MP_DEFINE_CONST_FUN_OBJ_2(Presto_set_backlight_obj, Presto_set_backlight);
 static const mp_rom_map_elem_t Presto_locals_dict_table[] = {
     { MP_ROM_QSTR(MP_QSTR___del__), MP_ROM_PTR(&Presto___del___obj) },
     { MP_ROM_QSTR(MP_QSTR_update), MP_ROM_PTR(&Presto_update_obj) },
+    { MP_ROM_QSTR(MP_QSTR_partial_update), MP_ROM_PTR(&Presto_partial_update_obj) },
     { MP_ROM_QSTR(MP_QSTR_set_backlight), MP_ROM_PTR(&Presto_set_backlight_obj) },
 
     { MP_ROM_QSTR(MP_QSTR_WIDTH), MP_ROM_INT(WIDTH/2) },
diff --git a/modules/c/presto/presto.cpp b/modules/c/presto/presto.cpp
index 74e2dc3..b6b221c 100644
--- a/modules/c/presto/presto.cpp
+++ b/modules/c/presto/presto.cpp
@@ -21,6 +21,7 @@ extern "C" {
 // MicroPython's GC heap will automatically resize, so we should just
 // statically allocate these in C++ to avoid fragmentation.
 __attribute__((section(".uninitialized_data"))) static uint16_t presto_buffer[WIDTH * HEIGHT] = {0};
+__attribute__((section(".psram_data"))) static uint16_t gfx_buffer[WIDTH * HEIGHT] = {0};
 
 void __printf_debug_flush() {
     for(auto i = 0u; i < 10; i++) {
@@ -44,7 +45,6 @@ void presto_debug(const char *fmt, ...) {
 typedef struct _Presto_obj_t {
     mp_obj_base_t base;
     ST7701* presto;
-    uint16_t* next_fb;
     uint16_t* curr_fb;
     uint16_t width;
     uint16_t height;
@@ -74,7 +74,7 @@ void presto_core1_entry() {
     multicore_fifo_push_blocking(0);
 }
 
-#define stack_size 4096u
+#define stack_size 256u
 static uint32_t core1_stack[stack_size] = {0};
 
 mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
@@ -93,23 +93,22 @@ mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw,
     self = mp_obj_malloc_with_finaliser(_Presto_obj_t, &Presto_type);
 
     presto_debug("set fb pointers\n");
-    self->curr_fb = presto_buffer;
-    self->next_fb = presto_buffer;
 
     if (!args[ARG_full_res].u_bool) {
+        self->curr_fb = presto_buffer + (WIDTH * HEIGHT) / 4;
         self->width = WIDTH / 2;
         self->height = HEIGHT / 2;
-        self->next_fb += (WIDTH * HEIGHT) / 4;
     }
     else {
         self->width = WIDTH;
         self->height = HEIGHT;
+        self->curr_fb = gfx_buffer;
     }
 
     presto_debug("m_new_class(ST7701...\n");
     ST7701 *presto = m_new_class(ST7701, self->width, self->height, ROTATE_0,
         SPIPins{spi1, LCD_CS, LCD_CLK, LCD_DAT, PIN_UNUSED, LCD_DC, BACKLIGHT},
-        self->next_fb,
+        presto_buffer,
         LCD_D0);
 
     self->presto = presto;
@@ -160,11 +159,34 @@ extern mp_obj_t Presto_update(mp_obj_t self_in, mp_obj_t graphics_in) {
     _Presto_obj_t *self = MP_OBJ_TO_PTR2(self_in, _Presto_obj_t);
     ModPicoGraphics_obj_t *picographics = MP_OBJ_TO_PTR2(graphics_in, ModPicoGraphics_obj_t);
 
-    self->presto->set_framebuffer(self->next_fb);
-    std::swap(self->next_fb, self->curr_fb);
-    picographics->graphics->set_framebuffer((void *)self->next_fb);
+    self->presto->update(picographics->graphics);
 
-    self->presto->wait_for_vsync();
+    return mp_const_none;
+}
+
+extern mp_obj_t Presto_partial_update(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
+    enum { ARG_self, ARG_graphics, ARG_x, ARG_y, ARG_w, ARG_h };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_graphics, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_x, MP_ARG_REQUIRED | MP_ARG_INT },
+        { MP_QSTR_y, MP_ARG_REQUIRED | MP_ARG_INT },
+        { MP_QSTR_w, MP_ARG_REQUIRED | MP_ARG_INT },
+        { MP_QSTR_h, MP_ARG_REQUIRED | MP_ARG_INT }
+    };
+
+    // Parse args.
+    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);
+
+    _Presto_obj_t *self = MP_OBJ_TO_PTR2(args[ARG_self].u_obj, _Presto_obj_t);
+    ModPicoGraphics_obj_t *picographics = MP_OBJ_TO_PTR2(args[ARG_graphics].u_obj, ModPicoGraphics_obj_t);
+    int x = args[ARG_x].u_int;
+    int y = args[ARG_y].u_int;
+    int w = args[ARG_w].u_int;
+    int h = args[ARG_h].u_int;
+
+    self->presto->partial_update(picographics->graphics, {x, y, w, h});
 
     return mp_const_none;
 }
diff --git a/modules/c/presto/presto.h b/modules/c/presto/presto.h
index 3c72a98..0896167 100644
--- a/modules/c/presto/presto.h
+++ b/modules/c/presto/presto.h
@@ -18,6 +18,7 @@ extern const mp_obj_type_t Presto_type;
 /***** Extern of Class Methods *****/
 extern mp_obj_t Presto_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args);
 extern mp_obj_t Presto_update(mp_obj_t self_in, mp_obj_t graphics_in);
+extern mp_obj_t Presto_partial_update(size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args);
 extern mp_int_t Presto_get_framebuffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, mp_uint_t flags);
 extern mp_obj_t Presto_set_backlight(mp_obj_t self_in, mp_obj_t brightness);
 extern mp_obj_t Presto___del__(mp_obj_t self_in);
\ No newline at end of file

From 612cdc3eb32154e37c3edc4652e7ec8e532eb5e3 Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 6/7] MicroPython: Switch to new style of enabling PSRAM.

---
 presto/mpconfigboard.cmake | 3 +++
 presto/mpconfigboard.h     | 1 -
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/presto/mpconfigboard.cmake b/presto/mpconfigboard.cmake
index 95c568d..ad4454d 100644
--- a/presto/mpconfigboard.cmake
+++ b/presto/mpconfigboard.cmake
@@ -13,6 +13,9 @@ set(MICROPY_FROZEN_MANIFEST ${MICROPY_BOARD_DIR}/manifest.py)
 # there needs to be some RAM reserved for the C heap
 set(MICROPY_C_HEAP_SIZE 4096)
 
+# Enable PSRAM
+set(MICROPY_HW_ENABLE_PSRAM ON)
+
 # Links micropy_lib_lwip and sets MICROPY_PY_LWIP = 1
 # Picked up and expanded upon in mpconfigboard.h
 set(MICROPY_PY_LWIP ON)
diff --git a/presto/mpconfigboard.h b/presto/mpconfigboard.h
index c7c5f25..29858de 100644
--- a/presto/mpconfigboard.h
+++ b/presto/mpconfigboard.h
@@ -30,7 +30,6 @@ int mp_hal_is_pin_reserved(int n);
 
 // Alias the chip select pin specified by presto.h
 #define MICROPY_HW_PSRAM_CS_PIN                 PIMORONI_PRESTO_PSRAM_CS_PIN
-#define MICROPY_HW_ENABLE_PSRAM                 (1)
 
 #define MICROPY_PY_THREAD                       (0)
 #define MICROPY_GC_SPLIT_HEAP                   (0)

From d9577e6cd20cae621fc820bfb8e18c53dd560e52 Mon Sep 17 00:00:00 2001
From: Mike Bell <mdb036@gmail.com>
Date: Sun, 17 Nov 2024 15:38:26 +0000
Subject: [PATCH 7/7] Improve overclockability.

---
 presto/presto.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/presto/presto.h b/presto/presto.h
index 864b5d8..78acd56 100644
--- a/presto/presto.h
+++ b/presto/presto.h
@@ -120,4 +120,7 @@
 #define PICO_RP2350_A2_SUPPORTED 1
 #endif
 
+// Increase the clock divider to allow additional overclocking headroom
+#define CYW43_PIO_CLOCK_DIV_INT 4
+
 #endif