diff --git a/.ci-local/libevent.py b/.ci-local/libevent.py
index 946216f..9bfdcd0 100644
--- a/.ci-local/libevent.py
+++ b/.ci-local/libevent.py
@@ -71,3 +71,10 @@ elif os.environ.get('WINE')=='32':
         F.write('\nCROSS_COMPILER_TARGET_ARCHS+=win32-x86-mingw\n')
 
     check_call('make -C bundle libevent.win32-x86-mingw', shell=True, env=env)
+
+elif os.environ.get('RTEMS_TARGET'):
+    print('Enable RTEMS')
+    with open('configure/CONFIG_SITE.local', 'a') as F:
+        F.write('\nCROSS_COMPILER_TARGET_ARCHS+=%s\n'%os.environ['RTEMS_TARGET'])
+
+    check_call('make -C bundle libevent.'+os.environ['RTEMS_TARGET'], shell=True, env=env)
diff --git a/.github/workflows/ci-scripts-build.yml b/.github/workflows/ci-scripts-build.yml
index 317edd0..098526d 100644
--- a/.github/workflows/ci-scripts-build.yml
+++ b/.github/workflows/ci-scripts-build.yml
@@ -28,7 +28,10 @@ jobs:
       BCFG: ${{ matrix.configuration }}
       BASE: ${{ matrix.base }}
       WINE: ${{ matrix.wine }}
+      RTEMS: ${{ matrix.rtems }}
+      RTEMS_TARGET: ${{ matrix.rtems_target }}
       LIBEVENT_TAG: ${{ matrix.libevent }}
+      TEST: ${{ matrix.test }}
       EXTRA: ${{ matrix.extra }}
       VV: "1"
     strategy:
@@ -56,6 +59,15 @@ jobs:
             base: "7.0"
             wine: "64"
 
+          - name: RTEMS5
+            os: ubuntu-20.04
+            cmp: gcc
+            configuration: default
+            base: "7.0"
+            rtems: "5"
+            rtems_target: RTEMS-pc686-qemu
+            test: NO
+ 
           - name: Native Linux with clang
             os: ubuntu-20.04
             cmp: clang
diff --git a/bundle/Makefile b/bundle/Makefile
index c85e846..e739098 100644
--- a/bundle/Makefile
+++ b/bundle/Makefile
@@ -60,7 +60,13 @@ ifneq (,$(filter win%,$(EPICS_HOST_ARCH)))
 CMAKEFLAGS += -G "MinGW Makefiles" -DCMAKE_C_COMPILER="$(CC)"
 endif
 
+ifneq (,$(filter RTEMS%,$(T_A)))
+CMAKE_TOOLCHAIN_$(T_A) = $(T_A).cmake
+CMAKE_TOOLCHAIN_D_$(T_A) = $(CMAKE_TOOLCHAIN_$(T_A))
+endif
+
 # toolchain file when cross compiling
+CMAKE_TOOLCHAIN_D ?= $(CMAKE_TOOLCHAIN_D_$(T_A))
 CMAKE_TOOLCHAIN ?= $(CMAKE_TOOLCHAIN_$(T_A))
 CMAKEFLAGS += $(if $(CMAKE_TOOLCHAIN),-DCMAKE_TOOLCHAIN_FILE=$(CMAKE_TOOLCHAIN))
 
@@ -107,7 +113,7 @@ else # T_A
 ifeq (YES,$(LIBEVENT_USE_CMAKE))
 # libevent >= 2.1 prefer CMake
 
-libevent.%:
+libevent.%: $(CMAKE_TOOLCHAIN_D)
 	$(CMAKE) $(CMAKEFLAGS) ../libevent
 	$(CMAKE) -E env --unset=MAKEFLAGS --unset=CC $(CMAKE) --build . $(CBUILDFLAGS) --target install
 ifneq (,$(filter %mingw,$(T_A)))
@@ -122,6 +128,22 @@ ifeq (NO,$(SHARED_LIBRARIES))
 endif
 endif
 
+EXPANDFLAGS = $(foreach var,$(EXPANDVARS),-D$(var)="$($(var))")
+
+ifneq (,$(filter RTEMS%,$(T_A)))
+# cf. cmake/RTEMS.cmake@
+EXPANDVARS+=RTEMS_CPU
+EXPANDVARS+=RTEMS_BSP
+EXPANDVARS+=RTEMS_VERSION
+EXPANDVARS+=RTEMS_BASE
+EXPANDVARS+=CPU_CFLAGS
+
+$(T_A).cmake: ../cmake/RTEMS.cmake@
+	$(PERL) $(TOOLS)/expandVars.pl -a $(T_A) -t $(INSTALL_LOCATION) $(EXPANDFLAGS) $< $@
+# can't use $(EXPAND_TOOL) as this def is in a RULES_ file...
+endif
+
+
 else
 # libevent 2.0 only autotools
 # only host CC supported
diff --git a/bundle/cmake/Platform/RTEMS-Initialize.cmake b/bundle/cmake/Platform/RTEMS-Initialize.cmake
new file mode 100644
index 0000000..a6b491c
--- /dev/null
+++ b/bundle/cmake/Platform/RTEMS-Initialize.cmake
@@ -0,0 +1,20 @@
+# man cmake-toolchains
+
+if(NOT RTEMS_BSP)
+    message(FATAL_ERROR "toolchain must set RTEMS_BSP")
+endif()
+if(NOT RTEMS_PREFIX)
+    message(FATAL_ERROR "toolchain must set RTEMS_PREFIX")
+endif()
+
+set(RTEMS_TARGET_PREFIX "${RTEMS_PREFIX}/${CMAKE_SYSTEM_PROCESSOR}-rtems${CMAKE_SYSTEM_VERSION}")
+set(RTEMS_TOOL_PREFIX "${RTEMS_PREFIX}/bin/${CMAKE_SYSTEM_PROCESSOR}-rtems${CMAKE_SYSTEM_VERSION}")
+
+
+set(CMAKE_C_COMPILER ${RTEMS_TOOL_PREFIX}-gcc)
+set(CMAKE_CXX_COMPILER ${RTEMS_TOOL_PREFIX}-g++)
+set(CMAKE_OBJCOPY ${RTEMS_TOOL_PREFIX}-objcopy)
+
+set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
diff --git a/bundle/cmake/Platform/RTEMS.cmake b/bundle/cmake/Platform/RTEMS.cmake
new file mode 100644
index 0000000..8bc504f
--- /dev/null
+++ b/bundle/cmake/Platform/RTEMS.cmake
@@ -0,0 +1,49 @@
+# to understand Platform/ read
+# https://github.com/Kitware/CMake/blob/f86d8009c6a4482c81221114a2b04b375564cc94/Source/cmGlobalGenerator.cxx#L461-L504
+
+set_property(GLOBAL PROPERTY TARGET_SUPPORTS_SHARED_LIBS FALSE)
+
+set(CMAKE_EXECUTABLE_SUFFIX ".elf")
+
+set(CMAKE_FIND_ROOT_PATH
+  "${RTEMS_TARGET_PREFIX}/${RTEMS_BSP}"
+  "${RTEMS_TARGET_PREFIX}"
+)
+
+set(CMAKE_SYSTEM_PREFIX_PATH ${CMAKE_FIND_ROOT_PATH})
+
+set(CMAKE_SYSTEM_INCLUDE_PATH
+  "${RTEMS_TARGET_PREFIX}/${RTEMS_BSP}/lib/include"
+  "${RTEMS_TARGET_PREFIX}/include"
+)
+set(CMAKE_C_IMPLICIT_INCLUDE_DIRECTORIES ${CMAKE_SYSTEM_INCLUDE_PATH})
+set(CMAKE_CXX_IMPLICIT_INCLUDE_DIRECTORIES ${CMAKE_SYSTEM_INCLUDE_PATH})
+
+set(CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES
+  "${RTEMS_TARGET_PREFIX}/${RTEMS_BSP}/lib"
+)
+set(CMAKE_SYSTEM_LIBRARY_PATH ${CMAKE_PLATFORM_IMPLICIT_LINK_DIRECTORIES})
+
+set(CMAKE_C_FLAGS_INIT
+ "-B${RTEMS_TARGET_PREFIX}/${RTEMS_BSP}/lib/ -specs bsp_specs -qrtems ${RTEMS_BSP_C_FLAGS}"
+)
+set(CMAKE_C_FLAGS_INIT ${CMAKE_C_FLAGS_INIT})
+
+set(CMAKE_EXE_LINKER_FLAGS_INIT "-u Init ${RTEMS_BSP_LINKER_FLAGS}")
+foreach(ldpart ${RTEMS_LDPARTS})
+  string(APPEND CMAKE_EXE_LINKER_FLAGS_INIT " ${RTEMS_TARGET_PREFIX}/${RTEMS_BSP}/lib/${ldpart}")
+endforeach()
+string(APPEND CMAKE_EXE_LINKER_FLAGS_INIT " -static")
+
+# Needed to pass to try_compile, but not to actual executables
+string(APPEND CMAKE_EXE_LINKER_FLAGS_INIT " -lrtemsdefaultconfig")
+
+# Would be nice to use instead, but break eg. CheckFunctionExists.cmake
+#set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
+
+
+# libbsd.a has some undefined symbols.  eg. iflib_pseudo_detach()
+string(APPEND CMAKE_EXE_LINKER_FLAGS_INIT " -Wl,--gc-sections")
+
+# Hack so that CheckFunctionExists.cmake will find network bits normally found in a libc
+set(CMAKE_REQUIRED_LIBRARIES "-lbsd")
diff --git a/bundle/cmake/RTEMS.cmake@ b/bundle/cmake/RTEMS.cmake@
new file mode 100644
index 0000000..8bdc8a7
--- /dev/null
+++ b/bundle/cmake/RTEMS.cmake@
@@ -0,0 +1,7 @@
+set(CMAKE_SYSTEM_NAME RTEMS)
+set(CMAKE_SYSTEM_PROCESSOR @RTEMS_CPU@)
+set(CMAKE_SYSTEM_VERSION @RTEMS_VERSION@)
+set(RTEMS_BSP @RTEMS_BSP@)
+set(RTEMS_PREFIX @RTEMS_BASE@)
+
+set(RTEMS_BSP_C_FLAGS "@CPU_CFLAGS@")
diff --git a/src/evhelper.cpp b/src/evhelper.cpp
index 7d691de..422e469 100644
--- a/src/evhelper.cpp
+++ b/src/evhelper.cpp
@@ -165,7 +165,16 @@ struct evbase::Pvt : public epicsThreadRunable
     {
         INST_COUNTER(evbaseRunning);
         try {
-            decltype (base) tbase(event_base_new());
+            evconfig conf(event_config_new());
+#ifdef __rtems__
+            /* with libbsd circa RTEMS 5.1
+             * TCP peer close/reset notifications appear to be lost.
+             * Maybe due to absence of NOTE_EOF?
+             * poll() seems to work though.
+             */
+            event_config_avoid_method(conf.get(), "kqueue");
+#endif
+            decltype (base) tbase(event_base_new_with_config(conf.get()));
             if(evthread_make_base_notifiable(tbase.get())) {
                 throw std::runtime_error("evthread_make_base_notifiable");
             }
diff --git a/src/evhelper.h b/src/evhelper.h
index 0c41c41..6beb0a8 100644
--- a/src/evhelper.h
+++ b/src/evhelper.h
@@ -25,6 +25,10 @@
 // hooks for std::unique_ptr
 namespace std {
 template<>
+struct default_delete<event_config> {
+    inline void operator()(event_config* ev) { event_config_free(ev); }
+};
+template<>
 struct default_delete<event_base> {
     inline void operator()(event_base* ev) { event_base_free(ev); }
 };
@@ -170,6 +174,7 @@ public:
     event_base* base = nullptr;
 };
 
+typedef owned_ptr<event_config> evconfig;
 typedef owned_ptr<event> evevent;
 typedef owned_ptr<evconnlistener> evlisten;
 typedef owned_ptr<bufferevent> evbufferevent;
diff --git a/test/Makefile b/test/Makefile
index 054a5d8..3fa7bab 100644
--- a/test/Makefile
+++ b/test/Makefile
@@ -102,6 +102,8 @@ testioc_SRCS += testioc_registerRecordDeviceDriver.cpp
 testioc_LIBS = pvxsIoc pvxs $(EPICS_BASE_IOC_LIBS)
 TESTS += testioc
 
+PROD_SRCS_RTEMS += rtemsTestData.c
+
 endif
 
 TESTPROD_HOST += mcat
@@ -109,6 +111,12 @@ mcat_SRCS += mcat.cpp
 # not a unittest
 
 TESTSCRIPTS_HOST += $(TESTS:%=%.t)
+ifdef BASE_3_15
+ifneq ($(filter $(T_A),$(CROSS_COMPILER_RUNTEST_ARCHS)),)
+TESTPROD = $(TESTPROD_HOST)
+TESTSCRIPTS = $(TESTSCRIPTS_HOST)
+endif
+endif
 
 #===========================
 
@@ -117,3 +125,7 @@ include $(TOP)/configure/RULES_PVXS_MODULE
 #----------------------------------------
 #  ADD RULES AFTER THIS LINE
 
+ifdef BASE_3_15
+rtemsTestData.c : $(TESTFILES) $(TOOLS)/epicsMakeMemFs.pl
+	$(PERL) $(TOOLS)/epicsMakeMemFs.pl $@ epicsRtemsFSImage $(TESTFILES)
+endif