diff --git a/drivers/pwm/pwm_cluster.cpp b/drivers/pwm/pwm_cluster.cpp
index 3c600619..8cf3e19f 100644
--- a/drivers/pwm/pwm_cluster.cpp
+++ b/drivers/pwm/pwm_cluster.cpp
@@ -25,10 +25,10 @@ uint8_t PWMCluster::claimed_sms[] = { 0x0, 0x0 };
 uint PWMCluster::pio_program_offset = 0;
 
 
-PWMCluster::PWMCluster(PIO pio, uint sm, uint pin_mask, bool loading_zone)
+PWMCluster::PWMCluster(PIO pio, uint sm, uint64_t pin_mask, bool loading_zone)
 : pio(pio)
 , sm(sm)
-, pin_mask(pin_mask & ((1u << NUM_BANK0_GPIOS) - 1))
+, pin_mask(pin_mask & ((1llu << NUM_BANK0_GPIOS) - 1))
 , channel_count(0)
 , wrap_level(0)
 , loading_zone(loading_zone) {
diff --git a/drivers/pwm/pwm_cluster.hpp b/drivers/pwm/pwm_cluster.hpp
index e233551a..224f974c 100644
--- a/drivers/pwm/pwm_cluster.hpp
+++ b/drivers/pwm/pwm_cluster.hpp
@@ -103,7 +103,7 @@ namespace pimoroni {
     PIO pio;
     uint sm;
     int dma_channel;
-    uint pin_mask;
+    uint64_t pin_mask;
     uint8_t channel_count;
     ChannelState channels[NUM_BANK0_GPIOS];
     uint8_t channel_to_pin_map[NUM_BANK0_GPIOS];
@@ -135,7 +135,7 @@ namespace pimoroni {
     // Constructors/Destructor
     //--------------------------------------------------
   public:
-    PWMCluster(PIO pio, uint sm, uint pin_mask, bool loading_zone = DEFAULT_USE_LOADING_ZONE);
+    PWMCluster(PIO pio, uint sm, uint64_t pin_mask, bool loading_zone = DEFAULT_USE_LOADING_ZONE);
     PWMCluster(PIO pio, uint sm, uint pin_base, uint pin_count, bool loading_zone = DEFAULT_USE_LOADING_ZONE);
     PWMCluster(PIO pio, uint sm, const uint8_t *pins, uint32_t length, bool loading_zone = DEFAULT_USE_LOADING_ZONE);
     PWMCluster(PIO pio, uint sm, std::initializer_list<uint8_t> pins, bool loading_zone = DEFAULT_USE_LOADING_ZONE);