diff --git a/ports/samd/clock_config.h b/ports/samd/clock_config.h
index 6e48b286f4..35b7e53281 100644
--- a/ports/samd/clock_config.h
+++ b/ports/samd/clock_config.h
@@ -29,6 +29,6 @@
 void init_clocks(uint32_t cpu_freq);
 void set_cpu_freq(uint32_t cpu_freq);
 uint32_t get_cpu_freq(void);
-uint32_t get_apb_freq(void);
+uint32_t get_peripheral_freq(void);
 void check_usb_recovery_mode(void);
 void enable_sercom_clock(int id);
diff --git a/ports/samd/machine_i2c.c b/ports/samd/machine_i2c.c
index 90ea5e10ca..25dfa99340 100644
--- a/ports/samd/machine_i2c.c
+++ b/ports/samd/machine_i2c.c
@@ -185,7 +185,7 @@ mp_obj_t machine_i2c_make_new(const mp_obj_type_t *type, size_t n_args, size_t n
     // baud = peripheral_freq / (2 * baudrate) - 5 - (rise_time * peripheral_freq) / 2
     // Just set the minimal configuration for standard and fast mode.
     // Set Baud. Assume ~300ns rise time. Maybe set later by a keyword argument.
-    i2c->I2CM.BAUD.reg = get_apb_freq() / (2 * self->freq) - 5 - (get_apb_freq() / 1000000) * RISETIME_NS / 2000;
+    i2c->I2CM.BAUD.reg = get_peripheral_freq() / (2 * self->freq) - 5 - (get_peripheral_freq() / 1000000) * RISETIME_NS / 2000;
 
     // Enable interrupts
     sercom_register_irq(self->id, &common_i2c_irq_handler);
diff --git a/ports/samd/machine_pwm.c b/ports/samd/machine_pwm.c
index 6f9ca42b1b..d987927d31 100644
--- a/ports/samd/machine_pwm.c
+++ b/ports/samd/machine_pwm.c
@@ -28,6 +28,7 @@
 #include "py/runtime.h"
 #include "py/mphal.h"
 #include "modmachine.h"
+#include "clock_config.h"
 
 #include "sam.h"
 #include "pin_af.h"
@@ -50,7 +51,7 @@ typedef struct _machine_pwm_obj_t {
 #define PWM_NOT_INIT    (0)
 #define PWM_CLK_READY   (1)
 #define PWM_TCC_ENABLED (2)
-#define PWM_MASTER_CLK  (48000000)
+#define PWM_MASTER_CLK  (get_peripheral_freq())
 #define PWM_FULL_SCALE  (65536)
 
 static Tcc *tcc_instance[] = TCC_INSTS;
diff --git a/ports/samd/machine_spi.c b/ports/samd/machine_spi.c
index ddb8756e9a..8321f19cf0 100644
--- a/ports/samd/machine_spi.c
+++ b/ports/samd/machine_spi.c
@@ -206,9 +206,9 @@ STATIC void machine_spi_init(mp_obj_base_t *self_in, size_t n_args, const mp_obj
         spi->SPI.CTRLC.reg = 1; // 1 clock cycle character spacing
         #endif
 
-        // SPI is driven by the clock of GCLK Generator 2, freq in bus_freq
+        // SPI is driven by the clock of GCLK Generator 2, freq by get_peripheral_freq()
         // baud = bus_freq / (2 * baudrate) - 1
-        uint32_t baud = get_apb_freq() / (2 * self->baudrate) - 1;
+        uint32_t baud = get_peripheral_freq() / (2 * self->baudrate) - 1;
         spi->SPI.BAUD.reg = baud; // Set Baud
 
         // Enable RXC interrupt only if miso is defined
diff --git a/ports/samd/machine_uart.c b/ports/samd/machine_uart.c
index 92e63ee51e..1031f26c26 100644
--- a/ports/samd/machine_uart.c
+++ b/ports/samd/machine_uart.c
@@ -276,9 +276,9 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
         while (uart->USART.SYNCBUSY.bit.CTRLB) {
         }
 
-        // USART is driven by the clock of GCLK Generator 2, freq by get_apb_freq()
+        // USART is driven by the clock of GCLK Generator 2, freq by get_peripheral_freq()
         // baud rate; 65536 * (1 - 16 * 115200/bus_freq)
-        uint32_t baud = 65536 - ((uint64_t)(65536 * 16) * self->baudrate + get_apb_freq() / 2) / get_apb_freq();
+        uint32_t baud = 65536 - ((uint64_t)(65536 * 16) * self->baudrate + get_peripheral_freq() / 2) / get_peripheral_freq();
         uart->USART.BAUD.bit.BAUD = baud; // Set Baud
 
         sercom_register_irq(self->id, &common_uart_irq_handler);
diff --git a/ports/samd/mcu/samd21/clock_config.c b/ports/samd/mcu/samd21/clock_config.c
index e330d7ba6a..2402ed2e31 100644
--- a/ports/samd/mcu/samd21/clock_config.c
+++ b/ports/samd/mcu/samd21/clock_config.c
@@ -33,7 +33,7 @@
 #include "samd_soc.h"
 
 static uint32_t cpu_freq = CPU_FREQ;
-static uint32_t apb_freq = APB_FREQ;
+static uint32_t peripheral_freq = DFLL48M_FREQ;
 static uint32_t dfll48m_calibration;
 
 int sercom_gclk_id[] = {
@@ -46,8 +46,8 @@ uint32_t get_cpu_freq(void) {
     return cpu_freq;
 }
 
-uint32_t get_apb_freq(void) {
-    return apb_freq;
+uint32_t get_peripheral_freq(void) {
+    return peripheral_freq;
 }
 
 void set_cpu_freq(uint32_t cpu_freq_arg) {
diff --git a/ports/samd/mcu/samd21/mpconfigmcu.h b/ports/samd/mcu/samd21/mpconfigmcu.h
index dd16a6c8af..ecb125bbdb 100644
--- a/ports/samd/mcu/samd21/mpconfigmcu.h
+++ b/ports/samd/mcu/samd21/mpconfigmcu.h
@@ -16,7 +16,7 @@
 #define MICROPY_HW_UART_TXBUF           (1)
 
 #define CPU_FREQ                        (48000000)
-#define APB_FREQ                        (48000000)
+#define DFLL48M_FREQ                    (48000000)
 
 #define IRQ_PRI_PENDSV                  ((1 << __NVIC_PRIO_BITS) - 1)
 
diff --git a/ports/samd/mcu/samd51/clock_config.c b/ports/samd/mcu/samd51/clock_config.c
index 62c05193dd..31c8f5a865 100644
--- a/ports/samd/mcu/samd51/clock_config.c
+++ b/ports/samd/mcu/samd51/clock_config.c
@@ -33,7 +33,7 @@
 #include "samd_soc.h"
 
 static uint32_t cpu_freq = CPU_FREQ;
-static uint32_t apb_freq = APB_FREQ;
+static uint32_t peripheral_freq = DFLL48M_FREQ;
 static uint32_t dfll48m_calibration;
 
 int sercom_gclk_id[] = {
@@ -49,8 +49,8 @@ uint32_t get_cpu_freq(void) {
     return cpu_freq;
 }
 
-uint32_t get_apb_freq(void) {
-    return apb_freq;
+uint32_t get_peripheral_freq(void) {
+    return peripheral_freq;
 }
 
 void set_cpu_freq(uint32_t cpu_freq_arg) {
@@ -181,7 +181,7 @@ void init_clocks(uint32_t cpu_freq) {
     while (GCLK->PCHCTRL[0].bit.CHEN == 0) {
     }
     // Step 2: Set the multiplication values. The offset of 16384 to the freq is for rounding.
-    OSCCTRL->DFLLMUL.reg = OSCCTRL_DFLLMUL_MUL((APB_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) |
+    OSCCTRL->DFLLMUL.reg = OSCCTRL_DFLLMUL_MUL((DFLL48M_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) |
         OSCCTRL_DFLLMUL_FSTEP(1) | OSCCTRL_DFLLMUL_CSTEP(1);
     while (OSCCTRL->DFLLSYNC.bit.DFLLMUL == 1) {
     }
@@ -200,7 +200,7 @@ void init_clocks(uint32_t cpu_freq) {
     #else // MICROPY_HW_XOSC32K
 
     // Derive GCLK1 from DFLL48M at DPLL0_REF_FREQ as defined in mpconfigboard.h (e.g. 32768 Hz)
-    GCLK->GENCTRL[1].reg = ((APB_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) << GCLK_GENCTRL_DIV_Pos
+    GCLK->GENCTRL[1].reg = ((DFLL48M_FREQ + DPLLx_REF_FREQ / 2) / DPLLx_REF_FREQ) << GCLK_GENCTRL_DIV_Pos
         | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
     while (GCLK->SYNCBUSY.bit.GENCTRL1) {
     }
@@ -236,7 +236,7 @@ void init_clocks(uint32_t cpu_freq) {
 
     set_cpu_freq(cpu_freq);
 
-    apb_freq = APB_FREQ;  // To be changed if CPU_FREQ < 48M
+    peripheral_freq = DFLL48M_FREQ;  // To be changed if CPU_FREQ < 48M
 
     // Setup GCLK2 for DPLL1 output (48 MHz)
     GCLK->GENCTRL[2].reg = GCLK_GENCTRL_DIV(1) | GCLK_GENCTRL_RUNSTDBY | GCLK_GENCTRL_GENEN | GCLK_GENCTRL_SRC_DFLL;
diff --git a/ports/samd/mcu/samd51/mpconfigmcu.h b/ports/samd/mcu/samd51/mpconfigmcu.h
index c3253fcbec..2c1ea7fee2 100644
--- a/ports/samd/mcu/samd51/mpconfigmcu.h
+++ b/ports/samd/mcu/samd51/mpconfigmcu.h
@@ -29,7 +29,7 @@ unsigned long trng_random_u32(void);
 #define MICROPY_HW_UART_TXBUF           (1)
 
 #define CPU_FREQ                        (120000000)
-#define APB_FREQ                        (48000000)
+#define DFLL48M_FREQ                    (48000000)
 #define DPLLx_REF_FREQ                  (32768)
 
 #define NVIC_PRIORITYGROUP_4            ((uint32_t)0x00000003)