diff --git a/py/builtin.c b/py/builtin.c
index 22c5ecfde3..11268aed18 100644
--- a/py/builtin.c
+++ b/py/builtin.c
@@ -157,7 +157,7 @@ STATIC mp_obj_t mp_builtin_dir(uint n_args, const mp_obj_t *args) {
     } else { // n_args == 1
         // make a list of names in the given object
         if (MP_OBJ_IS_TYPE(args[0], &mp_type_module)) {
-            map = mp_obj_module_get_globals(args[0]);
+            map = mp_obj_dict_get_map(mp_obj_module_get_globals(args[0]));
         } else {
             mp_obj_type_t *type;
             if (MP_OBJ_IS_TYPE(args[0], &mp_type_type)) {
@@ -174,7 +174,7 @@ STATIC mp_obj_t mp_builtin_dir(uint n_args, const mp_obj_t *args) {
     mp_obj_t dir = mp_obj_new_list(0, NULL);
     if (map != NULL) {
         for (uint i = 0; i < map->alloc; i++) {
-            if (map->table[i].key != MP_OBJ_NULL) {
+            if (MP_MAP_SLOT_IS_FILLED(map, i)) {
                 mp_obj_list_append(dir, map->table[i].key);
             }
         }
diff --git a/py/builtinimport.c b/py/builtinimport.c
index ae59ea795d..fd0689c681 100644
--- a/py/builtinimport.c
+++ b/py/builtinimport.c
@@ -87,8 +87,8 @@ void do_load(mp_obj_t module_obj, vstr_t *file) {
     mp_map_t *old_globals = mp_globals_get();
 
     // set the new context
-    mp_locals_set(mp_obj_module_get_globals(module_obj));
-    mp_globals_set(mp_obj_module_get_globals(module_obj));
+    mp_locals_set(mp_obj_dict_get_map(mp_obj_module_get_globals(module_obj)));
+    mp_globals_set(mp_obj_dict_get_map(mp_obj_module_get_globals(module_obj)));
 
     // parse the imported script
     mp_parse_error_kind_t parse_error_kind;
diff --git a/py/map.c b/py/map.c
index 933b5f8e29..5b9e803774 100644
--- a/py/map.c
+++ b/py/map.c
@@ -1,4 +1,5 @@
 #include <stdlib.h>
+#include <assert.h>
 
 #include "misc.h"
 #include "mpconfig.h"
@@ -285,7 +286,7 @@ mp_obj_t mp_set_lookup(mp_set_t *set, mp_obj_t index, mp_map_lookup_kind_t looku
 
 mp_obj_t mp_set_remove_first(mp_set_t *set) {
     for (uint pos = 0; pos < set->alloc; pos++) {
-        if (set->table[pos] != MP_OBJ_NULL && set->table[pos] != MP_OBJ_SENTINEL) {
+        if (MP_SET_SLOT_IS_FILLED(set, pos)) {
             mp_obj_t elem = set->table[pos];
             // delete element
             set->used--;
diff --git a/py/modarray.c b/py/modarray.c
index 51c221fff3..d8ff7158ff 100644
--- a/py/modarray.c
+++ b/py/modarray.c
@@ -9,16 +9,19 @@ STATIC const mp_map_elem_t mp_module_array_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_array), (mp_obj_t)&mp_type_array },
 };
 
-STATIC const mp_map_t mp_module_array_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(mp_module_array_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(mp_module_array_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)mp_module_array_globals_table,
+STATIC const mp_obj_dict_t mp_module_array_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(mp_module_array_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(mp_module_array_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)mp_module_array_globals_table,
+    },
 };
 
 const mp_obj_module_t mp_module_array = {
     .base = { &mp_type_module },
     .name = MP_QSTR_array,
-    .globals = (mp_map_t*)&mp_module_array_globals,
+    .globals = (mp_obj_dict_t*)&mp_module_array_globals,
 };
diff --git a/py/modcollections.c b/py/modcollections.c
index 3401600bb1..dbd1896f20 100644
--- a/py/modcollections.c
+++ b/py/modcollections.c
@@ -9,16 +9,19 @@ STATIC const mp_map_elem_t mp_module_collections_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_namedtuple), (mp_obj_t)&mp_namedtuple_obj },
 };
 
-STATIC const mp_map_t mp_module_collections_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(mp_module_collections_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(mp_module_collections_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)mp_module_collections_globals_table,
+STATIC const mp_obj_dict_t mp_module_collections_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(mp_module_collections_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(mp_module_collections_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)mp_module_collections_globals_table,
+    },
 };
 
 const mp_obj_module_t mp_module_collections = {
     .base = { &mp_type_module },
     .name = MP_QSTR_collections,
-    .globals = (mp_map_t*)&mp_module_collections_globals,
+    .globals = (mp_obj_dict_t*)&mp_module_collections_globals,
 };
diff --git a/py/modio.c b/py/modio.c
index ced3983581..ac5c7df9de 100644
--- a/py/modio.c
+++ b/py/modio.c
@@ -13,18 +13,21 @@ STATIC const mp_map_elem_t mp_module_io_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_open), (mp_obj_t)&mp_builtin_open_obj },
 };
 
-STATIC const mp_map_t mp_module_io_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(mp_module_io_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(mp_module_io_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)mp_module_io_globals_table,
+STATIC const mp_obj_dict_t mp_module_io_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(mp_module_io_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(mp_module_io_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)mp_module_io_globals_table,
+    },
 };
 
 const mp_obj_module_t mp_module_io = {
     .base = { &mp_type_module },
     .name = MP_QSTR_io,
-    .globals = (mp_map_t*)&mp_module_io_globals,
+    .globals = (mp_obj_dict_t*)&mp_module_io_globals,
 };
 
 #endif
diff --git a/py/modmath.c b/py/modmath.c
index f80b73ab52..c26ba16189 100644
--- a/py/modmath.c
+++ b/py/modmath.c
@@ -139,18 +139,21 @@ STATIC const mp_map_elem_t mp_module_math_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_lgamma), (mp_obj_t)&mp_math_lgamma_obj },
 };
 
-STATIC const mp_map_t mp_module_math_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(mp_module_math_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(mp_module_math_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)mp_module_math_globals_table,
+STATIC const mp_obj_dict_t mp_module_math_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(mp_module_math_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(mp_module_math_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)mp_module_math_globals_table,
+    },
 };
 
 const mp_obj_module_t mp_module_math = {
     .base = { &mp_type_module },
     .name = MP_QSTR_math,
-    .globals = (mp_map_t*)&mp_module_math_globals,
+    .globals = (mp_obj_dict_t*)&mp_module_math_globals,
 };
 
 #endif // MICROPY_ENABLE_FLOAT
diff --git a/py/modmicropython.c b/py/modmicropython.c
index 23187c03e9..ed245969cf 100644
--- a/py/modmicropython.c
+++ b/py/modmicropython.c
@@ -34,16 +34,19 @@ STATIC const mp_map_elem_t mp_module_micropython_globals_table[] = {
 #endif
 };
 
-STATIC const mp_map_t mp_module_micropython_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(mp_module_micropython_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(mp_module_micropython_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)mp_module_micropython_globals_table,
+STATIC const mp_obj_dict_t mp_module_micropython_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(mp_module_micropython_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(mp_module_micropython_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)mp_module_micropython_globals_table,
+    },
 };
 
 const mp_obj_module_t mp_module_micropython = {
     .base = { &mp_type_module },
     .name = MP_QSTR_micropython,
-    .globals = (mp_map_t*)&mp_module_micropython_globals,
+    .globals = (mp_obj_dict_t*)&mp_module_micropython_globals,
 };
diff --git a/py/obj.h b/py/obj.h
index eb447f916c..e800addade 100644
--- a/py/obj.h
+++ b/py/obj.h
@@ -115,6 +115,8 @@ typedef enum _mp_map_lookup_kind_t {
     MP_MAP_LOOKUP_REMOVE_IF_FOUND,    // 2
 } mp_map_lookup_kind_t;
 
+#define MP_MAP_SLOT_IS_FILLED(map, pos) ((map)->table[pos].key != MP_OBJ_NULL && (map)->table[pos].key != MP_OBJ_SENTINEL)
+
 void mp_map_init(mp_map_t *map, int n);
 void mp_map_init_fixed_table(mp_map_t *map, int n, const mp_obj_t *table);
 mp_map_t *mp_map_new(int n);
@@ -132,6 +134,8 @@ typedef struct _mp_set_t {
     mp_obj_t *table;
 } mp_set_t;
 
+#define MP_SET_SLOT_IS_FILLED(set, pos) ((set)->table[pos] != MP_OBJ_NULL && (set)->table[pos] != MP_OBJ_SENTINEL)
+
 void mp_set_init(mp_set_t *set, int n);
 mp_obj_t mp_set_lookup(mp_set_t *set, mp_obj_t index, mp_map_lookup_kind_t lookup_kind);
 mp_obj_t mp_set_remove_first(mp_set_t *set);
@@ -444,6 +448,7 @@ typedef struct _mp_obj_dict_t {
     mp_obj_base_t base;
     mp_map_t map;
 } mp_obj_dict_t;
+void mp_obj_dict_init(mp_obj_dict_t *dict, int n_args);
 uint mp_obj_dict_len(mp_obj_t self_in);
 mp_obj_t mp_obj_dict_store(mp_obj_t self_in, mp_obj_t key, mp_obj_t value);
 mp_obj_t mp_obj_dict_delete(mp_obj_t self_in, mp_obj_t key);
@@ -483,9 +488,9 @@ MP_DECLARE_CONST_FUN_OBJ(mp_identity_obj);
 typedef struct _mp_obj_module_t {
     mp_obj_base_t base;
     qstr name;
-    mp_map_t *globals;
+    mp_obj_dict_t *globals;
 } mp_obj_module_t;
-mp_map_t *mp_obj_module_get_globals(mp_obj_t self_in);
+mp_obj_dict_t *mp_obj_module_get_globals(mp_obj_t self_in);
 
 // staticmethod and classmethod types; defined here so we can make const versions
 // this structure is used for instances of both staticmethod and classmethod
diff --git a/py/objcell.c b/py/objcell.c
index a6922b018a..d8517587df 100644
--- a/py/objcell.c
+++ b/py/objcell.c
@@ -1,4 +1,3 @@
-
 #include "nlr.h"
 #include "misc.h"
 #include "mpconfig.h"
diff --git a/py/objdict.c b/py/objdict.c
index c09ccfbeec..5a314aed80 100644
--- a/py/objdict.c
+++ b/py/objdict.c
@@ -100,12 +100,12 @@ typedef struct _mp_obj_dict_it_t {
 STATIC mp_map_elem_t *dict_it_iternext_elem(mp_obj_t self_in) {
     mp_obj_dict_it_t *self = self_in;
     machine_uint_t max = self->dict->map.alloc;
-    mp_map_elem_t *table = self->dict->map.table;
+    mp_map_t *map = &self->dict->map;
 
     for (int i = self->cur; i < max; i++) {
-        if (table[i].key != MP_OBJ_NULL && table[i].key != MP_OBJ_SENTINEL) {
+        if (MP_MAP_SLOT_IS_FILLED(map, i)) {
             self->cur = i + 1;
-            return &(table[i]);
+            return &(map->table[i]);
         }
     }
 
@@ -463,10 +463,14 @@ const mp_obj_type_t mp_type_dict = {
     .locals_dict = (mp_obj_t)&dict_locals_dict,
 };
 
+void mp_obj_dict_init(mp_obj_dict_t *dict, int n_args) {
+    dict->base.type = &mp_type_dict;
+    mp_map_init(&dict->map, n_args);
+}
+
 mp_obj_t mp_obj_new_dict(int n_args) {
     mp_obj_dict_t *o = m_new_obj(mp_obj_dict_t);
-    o->base.type = &mp_type_dict;
-    mp_map_init(&o->map, n_args);
+    mp_obj_dict_init(o, n_args);
     return o;
 }
 
diff --git a/py/objmodule.c b/py/objmodule.c
index cc5944b665..783aa8a6fc 100644
--- a/py/objmodule.c
+++ b/py/objmodule.c
@@ -19,7 +19,7 @@ STATIC void module_print(void (*print)(void *env, const char *fmt, ...), void *e
 
 STATIC void module_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
     mp_obj_module_t *self = self_in;
-    mp_map_elem_t *elem = mp_map_lookup(self->globals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
+    mp_map_elem_t *elem = mp_map_lookup(&self->globals->map, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP);
     if (elem != NULL) {
         dest[0] = elem->value;
     }
@@ -28,7 +28,7 @@ STATIC void module_load_attr(mp_obj_t self_in, qstr attr, mp_obj_t *dest) {
 STATIC bool module_store_attr(mp_obj_t self_in, qstr attr, mp_obj_t value) {
     mp_obj_module_t *self = self_in;
     // TODO CPython allows STORE_ATTR to a module, but is this the correct implementation?
-    mp_map_lookup(self->globals, MP_OBJ_NEW_QSTR(attr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
+    mp_obj_dict_store(self->globals, MP_OBJ_NEW_QSTR(attr), value);
     return true;
 }
 
@@ -52,10 +52,10 @@ mp_obj_t mp_obj_new_module(qstr module_name) {
     mp_obj_module_t *o = m_new_obj(mp_obj_module_t);
     o->base.type = &mp_type_module;
     o->name = module_name;
-    o->globals = mp_map_new(1);
+    o->globals = mp_obj_new_dict(1);
 
     // store __name__ entry in the module
-    mp_map_lookup(o->globals, MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = MP_OBJ_NEW_QSTR(module_name);
+    mp_obj_dict_store(o->globals, MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(module_name));
 
     // store the new module into the slot in the global dict holding all modules
     el->value = o;
@@ -64,7 +64,7 @@ mp_obj_t mp_obj_new_module(qstr module_name) {
     return o;
 }
 
-mp_map_t *mp_obj_module_get_globals(mp_obj_t self_in) {
+mp_obj_dict_t *mp_obj_module_get_globals(mp_obj_t self_in) {
     assert(MP_OBJ_IS_TYPE(self_in, &mp_type_module));
     mp_obj_module_t *self = self_in;
     return self->globals;
diff --git a/py/objset.c b/py/objset.c
index 12c8cd25a5..9a7e6751f5 100644
--- a/py/objset.c
+++ b/py/objset.c
@@ -32,7 +32,7 @@ STATIC void set_print(void (*print)(void *env, const char *fmt, ...), void *env,
     bool first = true;
     print(env, "{");
     for (int i = 0; i < self->set.alloc; i++) {
-        if (self->set.table[i] != MP_OBJ_NULL && self->set.table[i] != MP_OBJ_SENTINEL) {
+        if (MP_SET_SLOT_IS_FILLED(&self->set, i)) {
             if (!first) {
                 print(env, ", ");
             }
@@ -80,12 +80,12 @@ STATIC mp_obj_t set_it_iternext(mp_obj_t self_in) {
     assert(MP_OBJ_IS_TYPE(self_in, &mp_type_set_it));
     mp_obj_set_it_t *self = self_in;
     machine_uint_t max = self->set->set.alloc;
-    mp_obj_t *table = self->set->set.table;
+    mp_set_t *set = &self->set->set;
 
     for (machine_uint_t i = self->cur; i < max; i++) {
-        if (table[i] != MP_OBJ_NULL && table[i] != MP_OBJ_SENTINEL) {
+        if (MP_SET_SLOT_IS_FILLED(set, i)) {
             self->cur = i + 1;
-            return table[i];
+            return set->table[i];
         }
     }
 
diff --git a/py/runtime.c b/py/runtime.c
index c7b34c1e17..a8bd36bfac 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -33,31 +33,26 @@ STATIC mp_map_t *map_locals;
 STATIC mp_map_t *map_globals;
 STATIC mp_map_t map_builtins;
 
-STATIC mp_map_t map_main;
+STATIC mp_obj_dict_t dict_main;
 
 const mp_obj_module_t mp_module___main__ = {
     .base = { &mp_type_module },
     .name = MP_QSTR___main__,
-    .globals = (mp_map_t*)&map_main,
+    .globals = (mp_obj_dict_t*)&dict_main,
 };
 
-// a good optimising compiler will inline this if necessary
-STATIC void mp_map_add_qstr(mp_map_t *map, qstr qstr, mp_obj_t value) {
-    mp_map_lookup(map, MP_OBJ_NEW_QSTR(qstr), MP_MAP_LOOKUP_ADD_IF_NOT_FOUND)->value = value;
-}
-
 void mp_init(void) {
     mp_emit_glue_init();
 
     // init global module stuff
     mp_module_init();
 
-    mp_map_init(&map_main, 1);
+    mp_obj_dict_init(&dict_main, 1);
     // add some builtins that can't be done in ROM
-    mp_map_add_qstr(&map_main, MP_QSTR___name__, MP_OBJ_NEW_QSTR(MP_QSTR___main__));
+    mp_obj_dict_store(&dict_main, MP_OBJ_NEW_QSTR(MP_QSTR___name__), MP_OBJ_NEW_QSTR(MP_QSTR___main__));
 
     // locals = globals for outer module (see Objects/frameobject.c/PyFrame_New())
-    map_locals = map_globals = &map_main;
+    map_locals = map_globals = &dict_main.map;
 
     // init built-in hash table
     mp_map_init(&map_builtins, 3);
@@ -1017,9 +1012,9 @@ mp_obj_t mp_import_from(mp_obj_t module, qstr name) {
 void mp_import_all(mp_obj_t module) {
     DEBUG_printf("import all %p\n", module);
 
-    mp_map_t *map = mp_obj_module_get_globals(module);
+    mp_map_t *map = mp_obj_dict_get_map(mp_obj_module_get_globals(module));
     for (uint i = 0; i < map->alloc; i++) {
-        if (map->table[i].key != MP_OBJ_NULL) {
+        if (MP_MAP_SLOT_IS_FILLED(map, i)) {
             mp_store_name(MP_OBJ_QSTR_VALUE(map->table[i].key), map->table[i].value);
         }
     }
diff --git a/stm/pybmodule.c b/stm/pybmodule.c
index 5ae65ad229..40275949fd 100644
--- a/stm/pybmodule.c
+++ b/stm/pybmodule.c
@@ -273,16 +273,19 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_Exti), (mp_obj_t)&exti_obj_type },
 };
 
-STATIC const mp_map_t pyb_module_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)pyb_module_globals_table,
+STATIC const mp_obj_dict_t pyb_module_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)pyb_module_globals_table,
+    },
 };
 
 const mp_obj_module_t pyb_module = {
     .base = { &mp_type_module },
     .name = MP_QSTR_pyb,
-    .globals = (mp_map_t*)&pyb_module_globals,
+    .globals = (mp_obj_dict_t*)&pyb_module_globals,
 };
diff --git a/stmhal/help.c b/stmhal/help.c
index 66484576bc..25d3fcb57e 100644
--- a/stmhal/help.c
+++ b/stmhal/help.c
@@ -59,7 +59,7 @@ STATIC mp_obj_t pyb_help(uint n_args, const mp_obj_t *args) {
 
         mp_map_t *map = NULL;
         if (MP_OBJ_IS_TYPE(args[0], &mp_type_module)) {
-            map = mp_obj_module_get_globals(args[0]);
+            map = mp_obj_dict_get_map(mp_obj_module_get_globals(args[0]));
         } else {
             mp_obj_type_t *type;
             if (MP_OBJ_IS_TYPE(args[0], &mp_type_type)) {
diff --git a/stmhal/modos.c b/stmhal/modos.c
index 6103b1b4fd..f160627525 100644
--- a/stmhal/modos.c
+++ b/stmhal/modos.c
@@ -162,16 +162,19 @@ STATIC const mp_map_elem_t os_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_urandom), (mp_obj_t)&os_urandom_obj },
 };
 
-STATIC const mp_map_t os_module_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(os_module_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(os_module_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)os_module_globals_table,
+STATIC const mp_obj_dict_t os_module_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(os_module_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(os_module_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)os_module_globals_table,
+    },
 };
 
 const mp_obj_module_t os_module = {
     .base = { &mp_type_module },
     .name = MP_QSTR_os,
-    .globals = (mp_map_t*)&os_module_globals,
+    .globals = (mp_obj_dict_t*)&os_module_globals,
 };
diff --git a/stmhal/modpyb.c b/stmhal/modpyb.c
index 6784081029..a6cb5adb6d 100644
--- a/stmhal/modpyb.c
+++ b/stmhal/modpyb.c
@@ -287,16 +287,19 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_Exti), (mp_obj_t)&exti_obj_type },
 };
 
-STATIC const mp_map_t pyb_module_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)pyb_module_globals_table,
+STATIC const mp_obj_dict_t pyb_module_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(pyb_module_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)pyb_module_globals_table,
+    },
 };
 
 const mp_obj_module_t pyb_module = {
     .base = { &mp_type_module },
     .name = MP_QSTR_pyb,
-    .globals = (mp_map_t*)&pyb_module_globals,
+    .globals = (mp_obj_dict_t*)&pyb_module_globals,
 };
diff --git a/stmhal/modtime.c b/stmhal/modtime.c
index 9756ec3b5a..c20752e21d 100644
--- a/stmhal/modtime.c
+++ b/stmhal/modtime.c
@@ -28,16 +28,19 @@ STATIC const mp_map_elem_t time_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_sleep), (mp_obj_t)&time_sleep_obj },
 };
 
-STATIC const mp_map_t time_module_globals = {
-    .all_keys_are_qstrs = 1,
-    .table_is_fixed_array = 1,
-    .used = sizeof(time_module_globals_table) / sizeof(mp_map_elem_t),
-    .alloc = sizeof(time_module_globals_table) / sizeof(mp_map_elem_t),
-    .table = (mp_map_elem_t*)time_module_globals_table,
+STATIC const mp_obj_dict_t time_module_globals = {
+    .base = {&mp_type_dict},
+    .map = {
+        .all_keys_are_qstrs = 1,
+        .table_is_fixed_array = 1,
+        .used = sizeof(time_module_globals_table) / sizeof(mp_map_elem_t),
+        .alloc = sizeof(time_module_globals_table) / sizeof(mp_map_elem_t),
+        .table = (mp_map_elem_t*)time_module_globals_table,
+    },
 };
 
 const mp_obj_module_t time_module = {
     .base = { &mp_type_module },
     .name = MP_QSTR_time,
-    .globals = (mp_map_t*)&time_module_globals,
+    .globals = (mp_obj_dict_t*)&time_module_globals,
 };