diff --git a/ports/stm32/mpconfigport.h b/ports/stm32/mpconfigport.h
index 3c44bddfd5..c3202d1f2e 100644
--- a/ports/stm32/mpconfigport.h
+++ b/ports/stm32/mpconfigport.h
@@ -123,7 +123,6 @@
 #define MICROPY_PY_MACHINE_SPI_LSB  (SPI_FIRSTBIT_LSB)
 #define MICROPY_PY_MACHINE_SOFTSPI  (1)
 #define MICROPY_PY_MACHINE_TIMER    (1)
-#define MICROPY_SOFT_TIMER_TICKS_MS uwTick
 #endif
 #define MICROPY_HW_SOFTSPI_MIN_DELAY (0)
 #define MICROPY_HW_SOFTSPI_MAX_BAUDRATE (HAL_RCC_GetSysClockFreq() / 48)
@@ -275,6 +274,9 @@ static inline mp_uint_t disable_irq(void) {
 #define MICROPY_THREAD_YIELD()
 #endif
 
+// Configuration for shared/runtime/softtimer.c.
+#define MICROPY_SOFT_TIMER_TICKS_MS uwTick
+
 // For regular code that wants to prevent "background tasks" from running.
 // These background tasks (LWIP, Bluetooth) run in PENDSV context.
 #define MICROPY_PY_PENDSV_ENTER   uint32_t atomic_state = raise_irq_pri(IRQ_PRI_PENDSV);