3 files changed, 22 insertions, 17 deletions

diff --git a/ports/esp32s2/common-hal/countio/Counter.c b/ports/esp32s2/common-hal/countio/Counter.c
index 81f9f7ad2..fe52d93ad 100644
--- a/ports/esp32s2/common-hal/countio/Counter.c
+++ b/ports/esp32s2/common-hal/countio/Counter.c
@@ -27,12 +27,15 @@
 #include "common-hal/countio/Counter.h"
 #include "common-hal/microcontroller/Pin.h"
 
+#include "py/runtime.h"
+#include "supervisor/shared/translate.h"
+
 void common_hal_countio_counter_construct(countio_counter_obj_t* self,
     const mcu_pin_obj_t* pin) {
     claim_pin(pin);
 
     // Prepare configuration for the PCNT unit
-    pcnt_config_t pcnt_config = {
+    const pcnt_config_t pcnt_config = {
         // Set PCNT input signal and control GPIOs
         .pulse_gpio_num = pin->number,
         .ctrl_gpio_num = PCNT_PIN_NOT_USED,
@@ -41,12 +44,15 @@ void common_hal_countio_counter_construct(countio_counter_obj_t* self,
         .pos_mode = PCNT_COUNT_INC,   // Count up on the positive edge
         .neg_mode = PCNT_COUNT_DIS,   // Keep the counter value on the negative edge
     };
+
     // Initialize PCNT unit
-    // This also sets pcnt_config.unit
-    peripherals_pcnt_init(&pcnt_config);
+    const int8_t unit = peripherals_pcnt_init(pcnt_config);
+    if (unit == -1) {
+        mp_raise_RuntimeError(translate("All PCNT units in use"));
+    }
 
     self->pin = pin->number;
-    self->unit = pcnt_config.unit;
+    self->unit = (pcnt_unit_t)unit;
 }
 
 bool common_hal_countio_counter_deinited(countio_counter_obj_t* self) {
diff --git a/ports/esp32s2/peripherals/pcnt.c b/ports/esp32s2/peripherals/pcnt.c
index e7eb32c1d..555a0ec1d 100644
--- a/ports/esp32s2/peripherals/pcnt.c
+++ b/ports/esp32s2/peripherals/pcnt.c
@@ -26,39 +26,38 @@
 
 #include "peripherals/pcnt.h"
 
-#include "py/runtime.h"
-#include "supervisor/shared/translate.h"
-
 #define PCNT_UNIT_ACTIVE    1
 #define PCNT_UNIT_INACTIVE  0
 
 static uint8_t pcnt_state[4];
 
-void peripherals_pcnt_init(pcnt_config_t* pcnt_config) {
+int peripherals_pcnt_init(pcnt_config_t pcnt_config) {
     // Look for available pcnt unit
     for (uint8_t i = 0; i<=3; i++) {
         if (pcnt_state[i] == PCNT_UNIT_INACTIVE) {
-            pcnt_config->unit = (pcnt_unit_t)i;
+            pcnt_config.unit = (pcnt_unit_t)i;
             pcnt_state[i] = PCNT_UNIT_ACTIVE;
             break;
         } else if (i == 3) {
-            mp_raise_RuntimeError(translate("All PCNT units in use"));
+            return -1;
         }
     }
 
     // Initialize PCNT unit
-    pcnt_unit_config(pcnt_config);
+    pcnt_unit_config(&pcnt_config);
 
     // Configure and enable the input filter
-    pcnt_set_filter_value(pcnt_config->unit, 100);
-    pcnt_filter_enable(pcnt_config->unit);
+    pcnt_set_filter_value(pcnt_config.unit, 100);
+    pcnt_filter_enable(pcnt_config.unit);
 
     // Initialize PCNT's counter
-    pcnt_counter_pause(pcnt_config->unit);
-    pcnt_counter_clear(pcnt_config->unit);
+    pcnt_counter_pause(pcnt_config.unit);
+    pcnt_counter_clear(pcnt_config.unit);
 
     // Everything is set up, now go to counting
-    pcnt_counter_resume(pcnt_config->unit);
+    pcnt_counter_resume(pcnt_config.unit);
+
+    return pcnt_config.unit;
 }
 
 void peripherals_pcnt_deinit(pcnt_unit_t* unit) {
diff --git a/ports/esp32s2/peripherals/pcnt.h b/ports/esp32s2/peripherals/pcnt.h
index 64072501c..abed80fd0 100644
--- a/ports/esp32s2/peripherals/pcnt.h
+++ b/ports/esp32s2/peripherals/pcnt.h
@@ -29,7 +29,7 @@
 
 #include "driver/pcnt.h"
 
-extern void peripherals_pcnt_init(pcnt_config_t* pcnt_config);
+extern int peripherals_pcnt_init(pcnt_config_t pcnt_config);
 extern void peripherals_pcnt_deinit(pcnt_unit_t* unit);
 
 #endif  // MICROPY_INCLUDED_ESP32S2_PERIPHERALS_PCNT_HANDLER_H