Badger2040: Enforce minimum update blocking time.

drivers/uc8151/uc8151.cpp

@@ -323,6 +323,8 @@ namespace pimoroni {
   void UC8151::setup(uint8_t speed) {
     reset();
 
+    _update_speed = speed;
+
     if(speed == 0) {
       command(PSR, {
         RES_128x296 | LUT_OTP | FORMAT_BW | SHIFT_RIGHT | BOOSTER_ON | RESET_NONE
@@ -468,6 +470,25 @@ namespace pimoroni {
     setup(speed);
   }
 
+  uint8_t UC8151::update_speed() {
+    return _update_speed;
+  }
+
+  uint32_t UC8151::update_time() {
+    switch(_update_speed) {
+      case 0:
+        return 5500;
+      case 1:
+        return 2600;
+      case 2:
+        return 1000;
+      case 3:
+        return 300;
+      default:
+        return 5500;
+    }
+  }
+
   void UC8151::partial_update(int x, int y, int w, int h, bool blocking) {
     // y is given in columns ("banks"), which are groups of 8 horiontal pixels
     // x is given in pixels

drivers/uc8151/uc8151.hpp

@@ -146,6 +146,8 @@ namespace pimoroni {
 
     bool inverted = false;
 
+    uint8_t _update_speed = 0;
+
   public:
     UC8151(uint16_t width, uint16_t height) :
       width(width), height(height), frame_buffer(new uint8_t[width * height / 8]) {
@@ -199,6 +201,8 @@ namespace pimoroni {
 
     void invert(bool invert);
     void update_speed(uint8_t speed);
+    uint8_t update_speed();
+    uint32_t update_time();
     void update(bool blocking = true);
     void partial_update(int x, int y, int w, int h, bool blocking = true);
     void off();

libraries/badger2040/badger2040.cpp

@@ -220,6 +220,10 @@ namespace pimoroni {
     uc8151.update_speed(speed);
   }
 
+  uint32_t Badger2040::update_time() {
+    return uc8151.update_time();
+  }
+
   void Badger2040::partial_update(int x, int y, int w, int h, bool blocking) {
     uc8151.partial_update(x, y, w, h, blocking);
   }

libraries/badger2040/badger2040.hpp

@@ -30,6 +30,7 @@ namespace pimoroni {
     void update(bool blocking=false);
     void partial_update(int x, int y, int w, int h, bool blocking=false);
     void update_speed(uint8_t speed);
+    uint32_t update_time();
     void halt();
     void sleep();
     bool is_busy();

micropython/modules/badger2040/badger2040.cpp

@@ -149,9 +149,12 @@ MICROPY_EVENT_POLL_HOOK
 #endif
     }
 
+    absolute_time_t t_end = make_timeout_time_ms(self->badger2040->update_time());
     self->badger2040->update(false);
 
-    while(self->badger2040->is_busy()) {
+    // Ensure blocking for the minimum amount of time
+    // in cases where "is_busy" is unreliable.
+    while(self->badger2040->is_busy() || absolute_time_diff_us(t_end, get_absolute_time()) > 0) {
 #ifdef MICROPY_EVENT_POLL_HOOK
 MICROPY_EVENT_POLL_HOOK
 #endif
@@ -190,9 +193,12 @@ MICROPY_EVENT_POLL_HOOK
 #endif
     }
 
+    absolute_time_t t_end = make_timeout_time_ms(self->badger2040->update_time());
     self->badger2040->partial_update(x, y, w, h);
 
-    while(self->badger2040->is_busy()) {
+    // Ensure blocking for the minimum amount of time
+    // in cases where "is_busy" is unreliable.
+    while(self->badger2040->is_busy() || absolute_time_diff_us(t_end, get_absolute_time()) > 0) {
 #ifdef MICROPY_EVENT_POLL_HOOK
 MICROPY_EVENT_POLL_HOOK
 #endif