diff --git a/klippy/extras/tmc_uart.py b/klippy/extras/tmc_uart.py
index 6db689a2..288fb76d 100644
--- a/klippy/extras/tmc_uart.py
+++ b/klippy/extras/tmc_uart.py
@@ -149,12 +149,14 @@ class MCU_TMC_uart_bitbang:
         params = self.tmcuart_send_cmd.send_with_response(
             [self.oid, msg, 10], 'tmcuart_response', self.oid)
         return self._decode_read(reg, params['read'])
-    def reg_write(self, instance_id, addr, reg, val):
+    def reg_write(self, instance_id, addr, reg, val, print_time=0.):
+        minclock = self.mcu.print_time_to_clock(print_time)
         if self.analog_mux is not None:
             self.analog_mux.activate(instance_id)
         msg = self._encode_write(0xf5, 0x00, reg | 0x80, val)
         self.tmcuart_send_cmd.send_with_response(
-            [self.oid, msg, 0], 'tmcuart_response', self.oid)
+            [self.oid, msg, 0], 'tmcuart_response', self.oid,
+            minclock=minclock)
 
 # Lookup a (possibly shared) tmc uart
 def lookup_tmc_uart_bitbang(config):
@@ -208,7 +210,8 @@ class MCU_TMC_uart:
             ifcnt = self.ifcnt
             if ifcnt is None:
                 self.ifcnt = ifcnt = self.get_register("IFCNT")
-            self.mcu_uart.reg_write(self.instance_id, self.addr, reg, val)
+            self.mcu_uart.reg_write(self.instance_id, self.addr, reg, val,
+                                    print_time)
             self.ifcnt = self.get_register("IFCNT")
             if self.ifcnt == (ifcnt + 1) & 0xff:
                 return