diff --git a/src/atsamd/adc.c b/src/atsamd/adc.c
index 59b12163..1322a46c 100644
--- a/src/atsamd/adc.c
+++ b/src/atsamd/adc.c
@@ -70,12 +70,9 @@ adc_init(void)
     // Enable adc clock
     enable_pclock(ADC_GCLK_ID, ID_ADC);
     // Load calibraiton info
-    uint32_t v = *((uint32_t*)ADC_FUSES_BIASCAL_ADDR);
-    uint32_t bias = (v & ADC_FUSES_BIASCAL_Msk) >> ADC_FUSES_BIASCAL_Pos;
-    v = *((uint32_t*)ADC_FUSES_LINEARITY_0_ADDR);
-    uint32_t li0 = (v & ADC_FUSES_LINEARITY_0_Msk) >> ADC_FUSES_LINEARITY_0_Pos;
-    v = *((uint32_t*)ADC_FUSES_LINEARITY_1_ADDR);
-    uint32_t li5 = (v & ADC_FUSES_LINEARITY_1_Msk) >> ADC_FUSES_LINEARITY_1_Pos;
+    uint32_t bias = GET_FUSE(ADC_FUSES_BIASCAL);
+    uint32_t li0 = GET_FUSE(ADC_FUSES_LINEARITY_0);
+    uint32_t li5 = GET_FUSE(ADC_FUSES_LINEARITY_1);
     uint32_t lin = li0 | (li5 << 5);
     ADC->CALIB.reg = ADC_CALIB_BIAS_CAL(bias) | ADC_CALIB_LINEARITY_CAL(lin);
 
@@ -92,22 +89,18 @@ adc_init(void)
 
     // Load calibration info
     // ADC0
-    uint32_t v = *((uint32_t*)ADC0_FUSES_BIASREFBUF_ADDR);
-    uint32_t refbuf = (v & ADC0_FUSES_BIASREFBUF_Msk) >> ADC0_FUSES_BIASREFBUF_Pos;
-    v = *((uint32_t*)ADC0_FUSES_BIASR2R_ADDR);
-    uint32_t r2r = (v & ADC0_FUSES_BIASR2R_Msk) >> ADC0_FUSES_BIASR2R_Pos;
-    v = *((uint32_t*)ADC0_FUSES_BIASCOMP_ADDR);
-    uint32_t comp = (v & ADC0_FUSES_BIASCOMP_Msk) >> ADC0_FUSES_BIASCOMP_Pos;
-    ADC0->CALIB.reg = ADC0_FUSES_BIASREFBUF(refbuf) | ADC0_FUSES_BIASR2R(r2r) | ADC0_FUSES_BIASCOMP(comp);
+    uint32_t refbuf = GET_FUSE(ADC0_FUSES_BIASREFBUF);
+    uint32_t r2r = GET_FUSE(ADC0_FUSES_BIASR2R);
+    uint32_t comp = GET_FUSE(ADC0_FUSES_BIASCOMP);
+    ADC0->CALIB.reg = (ADC0_FUSES_BIASREFBUF(refbuf)
+                       | ADC0_FUSES_BIASR2R(r2r) | ADC0_FUSES_BIASCOMP(comp));
 
     // ADC1
-    v = *((uint32_t*)ADC1_FUSES_BIASREFBUF_ADDR);
-    refbuf = (v & ADC1_FUSES_BIASREFBUF_Msk) >> ADC1_FUSES_BIASREFBUF_Pos;
-    v = *((uint32_t*)ADC1_FUSES_BIASR2R_ADDR);
-    r2r = (v & ADC1_FUSES_BIASR2R_Msk) >> ADC1_FUSES_BIASR2R_Pos;
-    v = *((uint32_t*)ADC1_FUSES_BIASCOMP_ADDR);
-    comp = (v & ADC1_FUSES_BIASCOMP_Msk) >> ADC1_FUSES_BIASCOMP_Pos;
-    ADC1->CALIB.reg = ADC1_FUSES_BIASREFBUF(refbuf) | ADC1_FUSES_BIASR2R(r2r) | ADC1_FUSES_BIASCOMP(comp);
+    refbuf = GET_FUSE(ADC1_FUSES_BIASREFBUF);
+    r2r = GET_FUSE(ADC1_FUSES_BIASR2R);
+    comp = GET_FUSE(ADC1_FUSES_BIASCOMP);
+    ADC1->CALIB.reg = (ADC0_FUSES_BIASREFBUF(refbuf)
+                       | ADC0_FUSES_BIASR2R(r2r) | ADC0_FUSES_BIASCOMP(comp));
 
     // Setup and enable
     // ADC0
diff --git a/src/atsamd/internal.h b/src/atsamd/internal.h
index ca748492..45d478b0 100644
--- a/src/atsamd/internal.h
+++ b/src/atsamd/internal.h
@@ -15,6 +15,9 @@
 #define GPIO2PORT(PIN) ((PIN) / 32)
 #define GPIO2BIT(PIN) (1<<((PIN) % 32))
 
+#define GET_FUSE(REG)                                           \
+    ((*((uint32_t*)(REG##_ADDR)) & (REG##_Msk)) >> (REG##_Pos))
+
 void enable_pclock(uint32_t pclk_id, uint32_t pm_id);
 uint32_t get_pclock_frequency(uint32_t pclk_id);
 void gpio_peripheral(uint32_t gpio, char ptype, int32_t pull_up);
diff --git a/src/atsamd/usbserial.c b/src/atsamd/usbserial.c
index 3ae73d9b..6b7e46b6 100644
--- a/src/atsamd/usbserial.c
+++ b/src/atsamd/usbserial.c
@@ -193,12 +193,9 @@ usbserial_init(void)
     uint32_t ptype = CONFIG_MACH_SAMD21 ? 'G' : 'H';
     gpio_peripheral(GPIO('A', 24), ptype, 0);
     gpio_peripheral(GPIO('A', 25), ptype, 0);
-    uint16_t trim = (readl((void*)USB_FUSES_TRIM_ADDR)
-                     & USB_FUSES_TRIM_Msk) >> USB_FUSES_TRIM_Pos;
-    uint16_t transp = (readl((void*)USB_FUSES_TRANSP_ADDR)
-                       & USB_FUSES_TRANSP_Msk) >> USB_FUSES_TRANSP_Pos;
-    uint16_t transn = (readl((void*)USB_FUSES_TRANSN_ADDR)
-                       & USB_FUSES_TRANSN_Msk) >> USB_FUSES_TRANSN_Pos;
+    uint32_t trim = GET_FUSE(USB_FUSES_TRIM);
+    uint32_t transp = GET_FUSE(USB_FUSES_TRANSP);
+    uint32_t transn = GET_FUSE(USB_FUSES_TRANSN);
     USB->DEVICE.PADCAL.reg = (USB_PADCAL_TRIM(trim) | USB_PADCAL_TRANSP(transp)
                               | USB_PADCAL_TRANSN(transn));
     // Enable USB in device mode