No longer fails, did not change anything

probably the probleme was the wire connecting gpoi17 to gnd ?

src/addons/psx.cpp

@@ -74,7 +74,14 @@ void PsxAddon::setup() {
 
 // Called after the gamepad is read, but before the read values are processed
 void PsxAddon::preprocess() {
-    Gamepad *gamepad = Storage::getInstance().GetGamepad();
+
+    // Blinks the LED on pin 25 to check that the Addon is still alive.
+    /*
+    gpio_init(25);
+    gpio_disable_pulls(25);
+    gpio_set_dir(25, GPIO_OUT);
+    gpio_put(25, !(to_ms_since_boot(get_absolute_time()) & (256 | 64)));
+    */
 
     takeAttention();
 
@@ -84,6 +91,8 @@ void PsxAddon::preprocess() {
     uint8_t answer1      = readwrite(0x00);     // MSB [LEFT] [DOWN] [RGHT] [ UP ] [STRT] [    ] [    ] [SLCT] LSB
     uint8_t answer2      = readwrite(0x00);     // MSB [ [] ] [ X  ] [ O  ] [ /\ ] [ R1 ] [ L1 ] [ R2 ] [ L2 ] LSB (bits are sent LSB first on protocol but read MSB first by the function)
 
+    Gamepad *gamepad = Storage::getInstance().GetGamepad();
+
     gamepad->state.buttons =
         0
         | ((answer2 & 0b01000000) ? 0 : GAMEPAD_MASK_B1)
@@ -135,15 +144,15 @@ uint8_t PsxAddon::readwrite(uint8_t sent) {
         sent = sent >> 1;
 
         gpio_put(clockPin, 0);
-        sleep_us(2);
+        sleep_us(1);
         gpio_put(clockPin, 1);
-
         sleep_us(1);
+
+        // instead of reading on rising edge of clock, we read as late as possible, just before setting clock low again
+        // because on some controllers, signal needs time to raise from 0V.
         received = received >> 1;
         received |= gpio_get(dataPin) ? 0b10000000 : 0;
-        sleep_us(1);
-
     }
 
     return received;
-}
+}