diff --git a/ports/cxd56/common-hal/analogio/AnalogIn.c b/ports/cxd56/common-hal/analogio/AnalogIn.c
index ebe291582a..e2ca5e4a42 100644
--- a/ports/cxd56/common-hal/analogio/AnalogIn.c
+++ b/ports/cxd56/common-hal/analogio/AnalogIn.c
@@ -68,9 +68,11 @@ void common_hal_analogio_analogin_construct(analogio_analogin_obj_t *self, const
         mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
     }
 
-    analogin_dev[self->number].fd = open(analogin_dev[pin->number].devpath, O_RDONLY);
     if (analogin_dev[self->number].fd < 0) {
-        mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
+        analogin_dev[self->number].fd = open(analogin_dev[self->number].devpath, O_RDONLY);
+        if (analogin_dev[self->number].fd < 0) {
+            mp_raise_ValueError(translate("Pin does not have ADC capabilities"));
+        }
     }
 
     // SCU FIFO overwrite
@@ -99,7 +101,7 @@ void common_hal_analogio_analogin_deinit(analogio_analogin_obj_t *self) {
 }
 
 bool common_hal_analogio_analogin_deinited(analogio_analogin_obj_t *self) {
-    return self->pin == mp_const_none;
+    return analogin_dev[self->number].fd < 0;
 }
 
 uint16_t common_hal_analogio_analogin_get_value(analogio_analogin_obj_t *self) {
diff --git a/ports/cxd56/common-hal/analogio/AnalogIn.h b/ports/cxd56/common-hal/analogio/AnalogIn.h
index 4e8b41e52b..9cf73003f5 100644
--- a/ports/cxd56/common-hal/analogio/AnalogIn.h
+++ b/ports/cxd56/common-hal/analogio/AnalogIn.h
@@ -34,7 +34,7 @@
 typedef struct {
     mp_obj_base_t base;
     const mcu_pin_obj_t *pin;
-    uint8_t number;
+    int8_t number;
 } analogio_analogin_obj_t;
 
 void analogin_reset(void);