diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/ICE40Top.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/ICE40Top.scala
index 43d80ab..cc03b96 100644
--- a/src/main/scala/ee/hrzn/chryse/platform/ice40/ICE40Top.scala
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/ICE40Top.scala
@@ -22,8 +22,8 @@ class ICE40Top[Top <: Module](
 
   private val clki = Wire(Clock())
 
-  private val clk_gb = Module(new SB_GB)
-  clk_gb.USER_SIGNAL_TO_GLOBAL_BUFFER := clki
+  private val clk_gb = Module(new SB_GB_IO)
+  clk_gb.PACKAGE_PIN := clki
   private val clk = clk_gb.GLOBAL_BUFFER_OUTPUT
 
   private val timerLimit = (15e-6 * platform.clockHz).toInt
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/IOStandard.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/IOStandard.scala
new file mode 100644
index 0000000..2be88ea
--- /dev/null
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/IOStandard.scala
@@ -0,0 +1,5 @@
+package ee.hrzn.chryse.platform.ice40
+
+object IOStandard {
+  val LV_CMOS = "SB_LVCMOS"
+}
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/IceBreakerPlatform.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/IceBreakerPlatform.scala
index 54a0188..71643ae 100644
--- a/src/main/scala/ee/hrzn/chryse/platform/ice40/IceBreakerPlatform.scala
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/IceBreakerPlatform.scala
@@ -24,7 +24,7 @@ final case class IceBreakerPlatform(ubtnReset: Boolean = false)
 }
 
 class IceBreakerPlatformResources extends PlatformBoardResources {
-  // TODO: IO_STANDARD=SB_LVCMOS needs to be set on most.
+  // TODO: IO_STANDARD=SB_LVCMOS needs to be set on most SB_IOs.
   val clock = resource.ClockSource(12_000_000).onPin(35)
 
   val ubtn = resource.Button().inverted.onPin(10)
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/PinType.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/PinType.scala
new file mode 100644
index 0000000..048b414
--- /dev/null
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/PinType.scala
@@ -0,0 +1,10 @@
+package ee.hrzn.chryse.platform.ice40
+
+// See SiliconBlue ICE™ Technology Library.
+object PinType {
+  val PIN_INPUT = 0x1
+
+  val PIN_NO_OUTPUT       = 0x0
+  val PIN_OUTPUT          = 0x18
+  val PIN_OUTPUT_TRISTATE = 0x28
+}
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB.scala
deleted file mode 100644
index 26725b1..0000000
--- a/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB.scala
+++ /dev/null
@@ -1,9 +0,0 @@
-package ee.hrzn.chryse.platform.ice40
-
-import chisel3._
-import chisel3.experimental.ExtModule
-
-class SB_GB extends ExtModule {
-  val USER_SIGNAL_TO_GLOBAL_BUFFER = IO(Input(Clock()))
-  val GLOBAL_BUFFER_OUTPUT         = IO(Output(Clock()))
-}
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB_IO.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB_IO.scala
new file mode 100644
index 0000000..2cb0797
--- /dev/null
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_GB_IO.scala
@@ -0,0 +1,15 @@
+package ee.hrzn.chryse.platform.ice40
+
+import chisel3._
+import chisel3.experimental.ExtModule
+
+class SB_GB_IO(pinType: Int = (PinType.PIN_INPUT | PinType.PIN_NO_OUTPUT))
+    extends ExtModule(
+      Map(
+        "IO_STANDARD" -> IOStandard.LV_CMOS,
+        "PIN_TYPE"    -> pinType,
+      ),
+    ) {
+  val PACKAGE_PIN          = IO(Input(Clock()))
+  val GLOBAL_BUFFER_OUTPUT = IO(Output(Clock()))
+}
diff --git a/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_IO.scala b/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_IO.scala
new file mode 100644
index 0000000..60743f4
--- /dev/null
+++ b/src/main/scala/ee/hrzn/chryse/platform/ice40/SB_IO.scala
@@ -0,0 +1,32 @@
+package ee.hrzn.chryse.platform.ice40
+
+import chisel3._
+import chisel3.experimental.Analog
+import chisel3.experimental.ExtModule
+
+class SB_IO(
+    pinType: Int,
+    ioStandard: String = IOStandard.LV_CMOS,
+    pullup: Boolean = false,
+) extends ExtModule(
+      Map(
+        "IO_STANDARD" -> ioStandard,
+        "PIN_TYPE"    -> pinType,
+        "PULLUP"      -> (if (pullup) 1 else 0),
+      ),
+    ) {
+
+  private def genPin(): Data = {
+    if (pinType == PinType.PIN_INPUT)
+      Input(Bool())
+    else if (pinType == PinType.PIN_OUTPUT)
+      Output(Bool())
+    else if (pinType == (PinType.PIN_INPUT | PinType.PIN_OUTPUT_TRISTATE))
+      Analog(1.W)
+    else
+      throw new IllegalArgumentException(s"unhandled pinType: $pinType")
+
+  }
+  val PACKAGE_PIN          = IO(genPin())
+  val GLOBAL_BUFFER_OUTPUT = IO(genPin())
+}