diff --git a/ports/esp32/modmachine.c b/ports/esp32/modmachine.c
index db77becf87..a70f2fbedb 100644
--- a/ports/esp32/modmachine.c
+++ b/ports/esp32/modmachine.c
@@ -82,8 +82,16 @@ STATIC mp_obj_t machine_freq(size_t n_args, const mp_obj_t *args) {
     } else {
         // set
         mp_int_t freq = mp_obj_get_int(args[0]) / 1000000;
-        if (freq != 20 && freq != 40 && freq != 80 && freq != 160 && freq != 240) {
+        if (freq != 20 && freq != 40 && freq != 80 && freq != 160
+            #if !CONFIG_IDF_TARGET_ESP32C3
+            && freq != 240
+            #endif
+            ) {
+            #if CONFIG_IDF_TARGET_ESP32C3
+            mp_raise_ValueError(MP_ERROR_TEXT("frequency must be 20MHz, 40MHz, 80Mhz or 160MHz"));
+            #else
             mp_raise_ValueError(MP_ERROR_TEXT("frequency must be 20MHz, 40MHz, 80Mhz, 160MHz or 240MHz"));
+            #endif
         }
         #if CONFIG_IDF_TARGET_ESP32
         esp_pm_config_esp32_t pm;