diff --git a/klippy/extras/tmc.py b/klippy/extras/tmc.py
index 46b9a8cf..f0a9ad38 100644
--- a/klippy/extras/tmc.py
+++ b/klippy/extras/tmc.py
@@ -96,7 +96,7 @@ class TMCCommandHelper:
             self.cmd_INIT_TMC, desc=self.cmd_INIT_TMC_help)
         self.printer.register_event_handler("klippy:connect",
                                             self._handle_connect)
-    def _init_registers(self, print_time):
+    def _init_registers(self, print_time=None):
         # Send registers
         for reg_name, val in self.fields.registers.items():
             self.mcu_tmc.set_register(reg_name, val, print_time)
@@ -104,7 +104,7 @@ class TMCCommandHelper:
         retry_count = 0
         while 1:
             try:
-                self._init_registers(0.)
+                self._init_registers()
                 return
             except self.printer.command_error as e:
                 logging.exception("TMC init error")
diff --git a/klippy/extras/tmc2130.py b/klippy/extras/tmc2130.py
index 4dce19c9..bb235962 100644
--- a/klippy/extras/tmc2130.py
+++ b/klippy/extras/tmc2130.py
@@ -186,12 +186,14 @@ class MCU_TMC_SPI:
         params = self.spi.spi_transfer([reg, 0x00, 0x00, 0x00, 0x00])
         pr = bytearray(params['response'])
         return (pr[1] << 24) | (pr[2] << 16) | (pr[3] << 8) | pr[4]
-    def set_register(self, reg_name, val, print_time=0.):
-        min_clock = self.spi.get_mcu().print_time_to_clock(print_time)
+    def set_register(self, reg_name, val, print_time=None):
+        minclock = 0
+        if print_time is not None:
+            minclock = self.spi.get_mcu().print_time_to_clock(print_time)
         reg = Registers[reg_name]
         data = [(reg | 0x80) & 0xff, (val >> 24) & 0xff, (val >> 16) & 0xff,
                 (val >> 8) & 0xff, val & 0xff]
-        self.spi.spi_send(data, min_clock)
+        self.spi.spi_send(data, minclock)
 
 
 ######################################################################
diff --git a/klippy/extras/tmc2660.py b/klippy/extras/tmc2660.py
index 893f8d1b..cb9b6c86 100644
--- a/klippy/extras/tmc2660.py
+++ b/klippy/extras/tmc2660.py
@@ -169,7 +169,8 @@ class TMC2660CurrentHelper:
         return vsense, cs
 
     def handle_printing(self, print_time):
-        self.set_current(0., self.current) # workaround
+        print_time -= 0.100 # Schedule slightly before deadline
+        self.set_current(print_time, self.current)
 
     def handle_ready(self, print_time):
         self.set_current(print_time, (float(self.idle_current_percentage)
@@ -213,15 +214,17 @@ class MCU_TMC2660_SPI:
         val = self.fields.set_field("RDSEL", ReadRegisters.index(reg_name))
         if self.printer.get_start_args().get('debugoutput') is not None:
             return 0
-        params = self.spi.spi_transfer([((val >> 16) | reg) & 0xff,
-                                        (val >> 8) & 0xff, val & 0xff])
+        msg = [((val >> 16) | reg) & 0xff, (val >> 8) & 0xff, val & 0xff]
+        params = self.spi.spi_transfer(msg)
         pr = bytearray(params['response'])
         return (pr[0] << 16) | (pr[1] << 8) | pr[2]
-    def set_register(self, reg_name, val, print_time=0.):
-        min_clock = self.spi.get_mcu().print_time_to_clock(print_time)
+    def set_register(self, reg_name, val, print_time=None):
+        minclock = 0
+        if print_time is not None:
+            minclock = self.spi.get_mcu().print_time_to_clock(print_time)
         reg = self.name_to_reg[reg_name]
-        self.spi.spi_send([((val >> 16) | reg) & 0xff,
-                            (val >> 8) & 0xff, val & 0xff], min_clock)
+        msg = [((val >> 16) | reg) & 0xff, (val >> 8) & 0xff, val & 0xff]
+        self.spi.spi_send(msg, minclock)
 
 
 ######################################################################
diff --git a/klippy/extras/tmc_uart.py b/klippy/extras/tmc_uart.py
index 288fb76d..f5584e8b 100644
--- a/klippy/extras/tmc_uart.py
+++ b/klippy/extras/tmc_uart.py
@@ -149,8 +149,10 @@ 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, print_time=0.):
-        minclock = self.mcu.print_time_to_clock(print_time)
+    def reg_write(self, instance_id, addr, reg, val, print_time=None):
+        minclock = 0
+        if print_time is not None:
+            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)