diff --git a/artiq/gateware/dsp/sawg.py b/artiq/gateware/dsp/sawg.py
index 4814f810b..73eb29318 100644
--- a/artiq/gateware/dsp/sawg.py
+++ b/artiq/gateware/dsp/sawg.py
@@ -90,7 +90,7 @@ class Config(Module):
                        Signal((width, True), reset=(1 << width - 1) - 1)]
                       for i in range(3)]
         self.clipped = [Signal(2) for i in range(3)]  # TODO
-        self.i = Endpoint([("addr", bits_for(1 + 4 + len(self.limits))),
+        self.i = Endpoint([("addr", bits_for(4 + 2*len(self.limits))),
                            ("data", 16)])
         self.ce = Signal()