diff --git a/frontends/PyCDE/src/esi.py b/frontends/PyCDE/src/esi.py
index 5a4a213caf..05670bf5ae 100644
--- a/frontends/PyCDE/src/esi.py
+++ b/frontends/PyCDE/src/esi.py
@@ -4,10 +4,10 @@
 
 from .common import (AppID, Input, Output, _PyProxy, PortError)
 from .module import Generator, Module, ModuleLikeBuilderBase, PortProxyBase
-from .signals import BundleSignal, ChannelSignal, Signal, _FromCirctValue
+from .signals import BundleSignal, ChannelSignal, Signal, Struct, _FromCirctValue
 from .system import System
 from .types import (Bits, Bundle, BundledChannel, Channel, ChannelDirection,
-                    Type, types, _FromCirctType)
+                    StructType, Type, types, UInt, _FromCirctType)
 
 from .circt import ir
 from .circt.dialects import esi as raw_esi, hw, msft
@@ -473,6 +473,21 @@ class PureModule(Module):
     esi.ESIPureModuleParamOp(name, type_attr)
 
 
+@ServiceDecl
+class MMIO:
+  """ESI standard service to request access to an MMIO region."""
+
+  read = ServiceDecl.From(
+      Bundle([
+          BundledChannel("offset", ChannelDirection.TO, Bits(32)),
+          BundledChannel("data", ChannelDirection.FROM, Bits(32))
+      ]))
+
+  @staticmethod
+  def _op(sym_name: ir.StringAttr):
+    return raw_esi.MMIOServiceDeclOp(sym_name)
+
+
 def package(sys: System):
   """Package all ESI collateral."""
 
diff --git a/frontends/PyCDE/test/test_esi.py b/frontends/PyCDE/test/test_esi.py
index 5a7319655c..e153bd3ab7 100644
--- a/frontends/PyCDE/test/test_esi.py
+++ b/frontends/PyCDE/test/test_esi.py
@@ -1,11 +1,12 @@
 # RUN: rm -rf %t
 # RUN: %PYTHON% %s %t 2>&1 | FileCheck %s
 
-from pycde import (Clock, Input, InputChannel, OutputChannel, Module, generator,
-                   types)
+from pycde import (Clock, Input, InputChannel, OutputChannel, Module, System,
+                   generator, types)
 from pycde import esi
 from pycde.common import AppID, Output, RecvBundle, SendBundle
 from pycde.constructs import Wire
+from pycde.esi import MMIO
 from pycde.types import (Bits, Bundle, BundledChannel, Channel,
                          ChannelDirection, ChannelSignaling, UInt, ClockType)
 from pycde.testing import unittestmodule
@@ -126,3 +127,23 @@ class RecvBundleTest(Module):
   def build(self):
     to_channels = self.b_recv.unpack(resp=self.i1_in)
     self.s1_out = to_channels['req']
+
+
+# CHECK-LABEL:  hw.module @MMIOReq()
+# CHECK-NEXT:     %c0_i32 = hw.constant 0 : i32
+# CHECK-NEXT:     %false = hw.constant false
+# CHECK-NEXT:     [[B:%.+]] = esi.service.req.to_client <@MMIO::@read>(#esi.appid<"mmio_req">) : !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>
+# CHECK-NEXT:     %chanOutput, %ready = esi.wrap.vr %c0_i32, %false : i32
+# CHECK-NEXT:     %offset = esi.bundle.unpack %chanOutput from [[B]] : !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>
+@unittestmodule(esi_sys=True)
+class MMIOReq(Module):
+
+  @generator
+  def build(ports):
+    c32 = Bits(32)(0)
+    c1 = Bits(1)(0)
+
+    read_bundle = MMIO.read(AppID("mmio_req"))
+
+    data, _ = Channel(Bits(32)).wrap(c32, c1)
+    _ = read_bundle.unpack(data=data)
diff --git a/lib/Dialect/ESI/ESIStdServices.cpp b/lib/Dialect/ESI/ESIStdServices.cpp
index 7c2f6c6d30..828da8fc90 100644
--- a/lib/Dialect/ESI/ESIStdServices.cpp
+++ b/lib/Dialect/ESI/ESIStdServices.cpp
@@ -89,10 +89,9 @@ void MMIOServiceDeclOp::getPortList(SmallVectorImpl<ServicePortInfo> &ports) {
       ServicePortInfo::Direction::toClient,
       ChannelBundleType::get(
           ctxt,
-          {BundledChannel{StringAttr::get(ctxt, "offset"),
-                          ChannelDirection::from,
+          {BundledChannel{StringAttr::get(ctxt, "offset"), ChannelDirection::to,
                           ChannelType::get(ctxt, IntegerType::get(ctxt, 32))},
-           BundledChannel{StringAttr::get(ctxt, "data"), ChannelDirection::to,
+           BundledChannel{StringAttr::get(ctxt, "data"), ChannelDirection::from,
                           ChannelType::get(ctxt, IntegerType::get(ctxt, 32))}},
           /*resettable=*/UnitAttr())});
   // Write only port.
@@ -101,10 +100,9 @@ void MMIOServiceDeclOp::getPortList(SmallVectorImpl<ServicePortInfo> &ports) {
       ServicePortInfo::Direction::toClient,
       ChannelBundleType::get(
           ctxt,
-          {BundledChannel{StringAttr::get(ctxt, "offset"),
-                          ChannelDirection::from,
+          {BundledChannel{StringAttr::get(ctxt, "offset"), ChannelDirection::to,
                           ChannelType::get(ctxt, IntegerType::get(ctxt, 32))},
-           BundledChannel{StringAttr::get(ctxt, "data"), ChannelDirection::from,
+           BundledChannel{StringAttr::get(ctxt, "data"), ChannelDirection::to,
                           ChannelType::get(ctxt, IntegerType::get(ctxt, 32))}},
           /*resettable=*/UnitAttr())});
 }
diff --git a/test/Dialect/ESI/services.mlir b/test/Dialect/ESI/services.mlir
index a3404d6267..697f69b5aa 100644
--- a/test/Dialect/ESI/services.mlir
+++ b/test/Dialect/ESI/services.mlir
@@ -205,11 +205,11 @@ hw.module @CallableAccel1(in %clk: !seq.clock, in %rst: i1) {
 }
 
 esi.service.std.mmio @mmio
-!mmioReq = !esi.bundle<[!esi.channel<i32> from "offset", !esi.channel<i32> to "data"]>
+!mmioReq = !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>
 
-// CONN-LABEL:  hw.module @MMIOManifest(in %clk : !seq.clock, in %rst : i1, in %manifest : !esi.bundle<[!esi.channel<i32> from "offset", !esi.channel<i32> to "data"]>) {
-// CONN-NEXT:     esi.manifest.req #esi.appid<"manifest">, <@mmio::@read> std "esi.service.std.mmio", toClient, !esi.bundle<[!esi.channel<i32> from "offset", !esi.channel<i32> to "data"]>
-// CONN-NEXT:     %data = esi.bundle.unpack %data from %manifest : !esi.bundle<[!esi.channel<i32> from "offset", !esi.channel<i32> to "data"]>
+// CONN-LABEL:  hw.module @MMIOManifest(in %clk : !seq.clock, in %rst : i1, in %manifest : !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>) {
+// CONN-NEXT:     esi.manifest.req #esi.appid<"manifest">, <@mmio::@read> std "esi.service.std.mmio", toClient, !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>
+// CONN-NEXT:     %offset = esi.bundle.unpack %offset from %manifest : !esi.bundle<[!esi.channel<i32> to "offset", !esi.channel<i32> from "data"]>
 hw.module @MMIOManifest(in %clk: !seq.clock, in %rst: i1) {
   %req = esi.service.req.to_client <@mmio::@read> (#esi.appid<"manifest">) : !mmioReq
   %loopback = esi.bundle.unpack %loopback from %req : !mmioReq