diff --git a/artiq/coredevice/fastino.py b/artiq/coredevice/fastino.py
index c2ea4ad2c..f0ab00cc2 100644
--- a/artiq/coredevice/fastino.py
+++ b/artiq/coredevice/fastino.py
@@ -3,13 +3,23 @@ streaming DAC.
 """
 from numpy import int32, int64
 
-from artiq.language.core import kernel, portable, delay, delay_mu
+from artiq.language.core import nac3, kernel, portable, KernelInvariant
 from artiq.coredevice.rtio import (rtio_output, rtio_output_wide,
                                    rtio_input_data)
 from artiq.language.units import ns
-from artiq.language.types import TInt32, TList
+from artiq.coredevice.core import Core
 
 
+# NAC3TODO work around https://git.m-labs.hk/M-Labs/nac3/issues/189
+@nac3
+class ValueError(Exception):
+    pass
+@nac3
+class NotImplementedError(Exception):
+    pass
+
+
+@nac3
 class Fastino:
     """Fastino 32-channel, 16-bit, 2.5 MS/s per channel streaming DAC
 
@@ -41,7 +51,11 @@ class Fastino:
     :param log2_width: Width of DAC channel group (logarithm base 2).
         Value must match the corresponding value in the RTIO PHY (gateware).
     """
-    kernel_invariants = {"core", "channel", "width", "t_frame"}
+
+    core: KernelInvariant[Core]
+    channel: KernelInvariant[int32]
+    width: KernelInvariant[int32]
+    t_frame: KernelInvariant[int64]
 
     def __init__(self, dmgr, channel, core_device="core", log2_width=0):
         self.channel = channel << 8
@@ -69,15 +83,15 @@ class Fastino:
         Note: On Fastino gateware before v0.2 this may lead to 0 voltage being emitted
         transiently.
         """
-        self.set_cfg(reset=0, afe_power_down=0, dac_clr=0, clr_err=1)
+        self.set_cfg(reset=False, afe_power_down=False, dac_clr=False, clr_err=True)
         delay_mu(self.t_frame)
-        self.set_cfg(reset=0, afe_power_down=0, dac_clr=0, clr_err=0)
+        self.set_cfg(reset=False, afe_power_down=False, dac_clr=False, clr_err=False)
         delay_mu(self.t_frame)
         self.set_continuous(0)
         delay_mu(self.t_frame)
         self.stage_cic(1)
         delay_mu(self.t_frame)
-        self.apply_cic(0xffffffff)
+        self.apply_cic(int32(int64(0xffffffff)))
         delay_mu(self.t_frame)
         self.set_leds(0)
         delay_mu(self.t_frame)
@@ -85,7 +99,7 @@ class Fastino:
         delay_mu(self.t_frame)
 
     @kernel
-    def write(self, addr, data):
+    def write(self, addr: int32, data: int32):
         """Write data to a Fastino register.
 
         :param addr: Address to write to.
@@ -94,7 +108,7 @@ class Fastino:
         rtio_output(self.channel | addr, data)
 
     @kernel
-    def read(self, addr):
+    def read(self, addr: int32):
         """Read from Fastino register.
 
         TODO: untested
@@ -102,12 +116,12 @@ class Fastino:
         :param addr: Address to read from.
         :return: The data read.
         """
-        raise NotImplementedError
+        raise NotImplementedError()
         # rtio_output(self.channel | addr | 0x80)
         # return rtio_input_data(self.channel >> 8)
 
     @kernel
-    def set_dac_mu(self, dac, data):
+    def set_dac_mu(self, dac: int32, data: int32):
         """Write DAC data in machine units.
 
         :param dac: DAC channel to write to (0-31).
@@ -117,7 +131,7 @@ class Fastino:
         self.write(dac, data)
 
     @kernel
-    def set_group_mu(self, dac: TInt32, data: TList(TInt32)):
+    def set_group_mu(self, dac: int32, data: list[int32]):
         """Write a group of DAC channels in machine units.
 
         :param dac: First channel in DAC channel group (0-31). The `log2_width`
@@ -127,24 +141,24 @@ class Fastino:
             If the list length is less than group size, the remaining
             DAC channels within the group are cleared to 0 (machine units).
         """
-        if dac & (self.width - 1):
+        if dac & (self.width - 1) != 0:
             raise ValueError("Group index LSBs must be zero")
         rtio_output_wide(self.channel | dac, data)
 
     @portable
-    def voltage_to_mu(self, voltage):
+    def voltage_to_mu(self, voltage: float) -> int32:
         """Convert SI Volts to DAC machine units.
 
         :param voltage: Voltage in SI Volts.
         :return: DAC data word in machine units, 16 bit integer.
         """
-        data = int32(round((0x8000/10.)*voltage)) + int32(0x8000)
+        data = int32(round((float(0x8000)/10.)*voltage)) + int32(0x8000)
         if data < 0 or data > 0xffff:
             raise ValueError("DAC voltage out of bounds")
         return data
 
     @portable
-    def voltage_group_to_mu(self, voltage, data):
+    def voltage_group_to_mu(self, voltage: list[float], data: list[int32]):
         """Convert SI Volts to packed DAC channel group machine units.
 
         :param voltage: List of SI Volt voltages.
@@ -153,12 +167,12 @@ class Fastino:
         """
         for i in range(len(voltage)):
             v = self.voltage_to_mu(voltage[i])
-            if i & 1:
+            if i & 1 != 0:
                 v = data[i // 2] | (v << 16)
             data[i // 2] = int32(v)
 
     @kernel
-    def set_dac(self, dac, voltage):
+    def set_dac(self, dac: int32, voltage: float):
         """Set DAC data to given voltage.
 
         :param dac: DAC channel (0-31).
@@ -167,18 +181,18 @@ class Fastino:
         self.write(dac, self.voltage_to_mu(voltage))
 
     @kernel
-    def set_group(self, dac, voltage):
+    def set_group(self, dac: int32, voltage: list[float]):
         """Set DAC group data to given voltage.
 
         :param dac: DAC channel (0-31).
         :param voltage: Desired output voltage.
         """
-        data = [int32(0)] * (len(voltage) // 2)
+        data = [int32(0) for _ in range(len(voltage) // 2)]
         self.voltage_group_to_mu(voltage, data)
         self.set_group_mu(dac, data)
 
     @kernel
-    def update(self, update):
+    def update(self, update: int32):
         """Schedule channels for update.
 
         :param update: Bit mask of channels to update (32 bit).
@@ -186,7 +200,7 @@ class Fastino:
         self.write(0x20, update)
 
     @kernel
-    def set_hold(self, hold):
+    def set_hold(self, hold: int32):
         """Set channels to manual update.
 
         :param hold: Bit mask of channels to hold (32 bit).
@@ -194,7 +208,7 @@ class Fastino:
         self.write(0x21, hold)
 
     @kernel
-    def set_cfg(self, reset=0, afe_power_down=0, dac_clr=0, clr_err=0):
+    def set_cfg(self, reset: bool = False, afe_power_down: bool = False, dac_clr: bool = False, clr_err: bool = False):
         """Set configuration bits.
 
         :param reset: Reset SPI PLL and SPI clock domain.
@@ -205,11 +219,11 @@ class Fastino:
             This clears the sticky red error LED. Must be cleared to enable
             error counting.
         """
-        self.write(0x22, (reset << 0) | (afe_power_down << 1) |
-                   (dac_clr << 2) | (clr_err << 3))
+        self.write(0x22, (int32(reset) << 0) | (int32(afe_power_down) << 1) |
+                   (int32(dac_clr) << 2) | (int32(clr_err) << 3))
 
     @kernel
-    def set_leds(self, leds):
+    def set_leds(self, leds: int32):
         """Set the green user-defined LEDs
 
         :param leds: LED status, 8 bit integer each bit corresponding to one
@@ -218,14 +232,14 @@ class Fastino:
         self.write(0x23, leds)
 
     @kernel
-    def set_continuous(self, channel_mask):
+    def set_continuous(self, channel_mask: int32):
         """Enable continuous DAC updates on channels regardless of new data
         being submitted.
         """
         self.write(0x25, channel_mask)
 
     @kernel
-    def stage_cic_mu(self, rate_mantissa, rate_exponent, gain_exponent):
+    def stage_cic_mu(self, rate_mantissa: int32, rate_exponent: int32, gain_exponent: int32):
         """Stage machine unit CIC interpolator configuration.
         """
         if rate_mantissa < 0 or rate_mantissa >= 1 << 6:
@@ -238,7 +252,7 @@ class Fastino:
         self.write(0x26, config)
 
     @kernel
-    def stage_cic(self, rate) -> TInt32:
+    def stage_cic(self, rate: int32) -> int32:
         """Compute and stage interpolator configuration.
 
         This method approximates the desired interpolation rate using a 10 bit
@@ -269,12 +283,12 @@ class Fastino:
         while gain > 1 << gain_exponent:
             gain_exponent += 1
         gain_exponent += order*rate_exponent
-        assert gain_exponent <= order*16
+        # NAC3TODO assert gain_exponent <= order*16
         self.stage_cic_mu(rate_mantissa - 1, rate_exponent, gain_exponent)
         return rate_mantissa << rate_exponent
 
     @kernel
-    def apply_cic(self, channel_mask):
+    def apply_cic(self, channel_mask: int32):
         """Apply the staged interpolator configuration on the specified channels.
 
         Each Fastino channel starting with gateware v0.2 includes a fourth order
diff --git a/artiq/examples/nac3devices/nac3devices.json b/artiq/examples/nac3devices/nac3devices.json
index aae7184fe..1b547d26d 100644
--- a/artiq/examples/nac3devices/nac3devices.json
+++ b/artiq/examples/nac3devices/nac3devices.json
@@ -36,6 +36,10 @@
         {
             "type": "grabber",
             "ports": [6]
+        },
+        {
+            "type": "fastino",
+            "ports": [7]
         }
     ]
 }
diff --git a/artiq/examples/nac3devices/nac3devices.py b/artiq/examples/nac3devices/nac3devices.py
index b979bd19c..ea46f72e5 100644
--- a/artiq/examples/nac3devices/nac3devices.py
+++ b/artiq/examples/nac3devices/nac3devices.py
@@ -9,6 +9,7 @@ from artiq.coredevice.ad9912 import AD9912
 from artiq.coredevice.sampler import Sampler
 from artiq.coredevice.edge_counter import EdgeCounter
 from artiq.coredevice.grabber import Grabber
+from artiq.coredevice.fastino import Fastino
 
 
 @nac3
@@ -23,6 +24,7 @@ class NAC3Devices(EnvExperiment):
     sampler0: KernelInvariant[Sampler]
     ttl0_counter: KernelInvariant[EdgeCounter]
     grabber0: KernelInvariant[Grabber]
+    fastino0: KernelInvariant[Fastino]
 
     def build(self):
         self.setattr_device("core")
@@ -35,6 +37,7 @@ class NAC3Devices(EnvExperiment):
         self.setattr_device("sampler0")
         self.setattr_device("ttl0_counter")
         self.setattr_device("grabber0")
+        self.setattr_device("fastino0")
 
     @kernel
     def run(self):