diff --git a/milkymist/framebuffer/__init__.py b/milkymist/framebuffer/__init__.py
index 7a7dbc97f..add483139 100644
--- a/milkymist/framebuffer/__init__.py
+++ b/milkymist/framebuffer/__init__.py
@@ -2,7 +2,7 @@ from migen.fhdl.structure import *
 from migen.flow.actor import *
 from migen.flow.network import *
 from migen.flow import plumbing
-from migen.actorlib import misc, dma_asmi, structuring, sim
+from migen.actorlib import misc, dma_asmi, structuring, sim, spi
 from migen.bank.description import *
 from migen.bank import csrgen
 
@@ -27,69 +27,23 @@ _dac_layout = [
 	("r", BV(_bpc_dac))
 ]
 
-class _FrameInitiator(Actor):
+class _FrameInitiator(spi.SingleGenerator):
 	def __init__(self, asmi_bits, length_bits, alignment_bits):
-		self._alignment_bits = alignment_bits
-		
-		self._enable = RegisterField("enable")
-		
-		self._hres = RegisterField("hres", _hbits, reset=640)
-		self._hsync_start = RegisterField("hsync_start", _hbits, reset=656)
-		self._hsync_end = RegisterField("hsync_end", _hbits, reset=752)
-		self._hscan = RegisterField("hscan", _hbits, reset=799)
-		
-		self._vres = RegisterField("vres", _vbits, reset=480)
-		self._vsync_start = RegisterField("vsync_start", _vbits, reset=492)
-		self._vsync_end = RegisterField("vsync_end", _vbits, reset=494)
-		self._vscan = RegisterField("vscan", _vbits, reset=524)
-		
-		self._base = RegisterField("base", asmi_bits + self._alignment_bits)
-		self._length = RegisterField("length", length_bits + self._alignment_bits, reset=640*480*4)
-		
 		layout = [
-			("hres", BV(_hbits)),
-			("hsync_start", BV(_hbits)),
-			("hsync_end", BV(_hbits)),
-			("hscan", BV(_hbits)),
-			("vres", BV(_vbits)),
-			("vsync_start", BV(_vbits)),
-			("vsync_end", BV(_vbits)),
-			("vscan", BV(_vbits)),
-			("base", BV(asmi_bits)),
-			("length", BV(length_bits))
+			("hres", BV(_hbits), 640),
+			("hsync_start", BV(_hbits), 656),
+			("hsync_end", BV(_hbits), 752),
+			("hscan", BV(_hbits), 799),
+			
+			("vres", BV(_vbits), 480),
+			("vsync_start", BV(_vbits), 492),
+			("vsync_end", BV(_vbits), 494),
+			("vscan", BV(_vbits), 524),
+			
+			("base", BV(asmi_bits), 0, alignment_bits),
+			("length", BV(length_bits), 640*480*4, alignment_bits)
 		]
-		super().__init__(("frame", Source, layout))
-		
-	def get_registers(self):
-		return [self._enable,
-			self._hres, self._hsync_start, self._hsync_end, self._hscan,
-			self._vres, self._vsync_start, self._vsync_end, self._vscan,
-			self._base, self._length]
-		
-	def get_fragment(self):
-		# TODO: make address updates atomic
-		token = self.token("frame")
-		stb = self.endpoints["frame"].stb
-		ack = self.endpoints["frame"].ack
-		comb = [
-			self.busy.eq(stb),
-			token.hres.eq(self._hres.field.r),
-			token.hsync_start.eq(self._hsync_start.field.r),
-			token.hsync_end.eq(self._hsync_end.field.r),
-			token.hscan.eq(self._hscan.field.r),
-			token.vres.eq(self._vres.field.r),
-			token.vsync_start.eq(self._vsync_start.field.r),
-			token.vsync_end.eq(self._vsync_end.field.r),
-			token.vscan.eq(self._vscan.field.r),
-			token.length.eq(self._length.field.r[self._alignment_bits:])
-		]
-		sync = [
-			If(ack | ~stb,
-				stb.eq(self._enable.field.r),
-				token.base.eq(self._base.field.r[self._alignment_bits:])
-			)
-		]
-		return Fragment(comb, sync)
+		super().__init__(layout, spi.MODE_CONTINUOUS)
 
 class VTG(Actor):
 	def __init__(self):