diff --git a/ports/rp2/modules/rp2.py b/ports/rp2/modules/rp2.py
index c7e4d1fdd9..1e4bb26cf0 100644
--- a/ports/rp2/modules/rp2.py
+++ b/ports/rp2/modules/rp2.py
@@ -88,6 +88,10 @@ class PIOASMEmit:
     def side(self, value):
         self.num_sideset += 1
         if self.pass_ > 0:
+            if self.sideset_count == 0:
+                raise PIOASMError("no sideset")
+            elif value >= (1 << self.sideset_count):
+                raise PIOASMError("sideset too large")
             set_bit = 13 - self.sideset_count
             self.prog[_PROG_DATA][-1] |= self.sideset_opt << 12 | value << set_bit
         return self
@@ -269,17 +273,17 @@ def asm_pio(**kw):
 
 
 # sideset_count is inclusive of enable bit
-def asm_pio_encode(instr, sideset_count):
+def asm_pio_encode(instr, sideset_count, sideset_opt=False):
     emit = PIOASMEmit()
-    emit.delay_max = 31
     emit.sideset_count = sideset_count
-    if emit.sideset_count:
-        emit.delay_max >>= emit.sideset_count
+    emit.sideset_opt = sideset_opt != 0
+    emit.delay_max = 31 >> (emit.sideset_count + emit.sideset_opt)
     emit.pass_ = 1
     emit.num_instr = 0
     emit.num_sideset = 0
 
     gl = _pio_funcs
+    gl["word"] = emit.word
     gl["nop"] = emit.nop
     # gl["jmp"] = emit.jmp currently not supported
     gl["wait"] = emit.wait
diff --git a/ports/rp2/rp2_pio.c b/ports/rp2/rp2_pio.c
index 414fa8bd70..fe09ebe249 100644
--- a/ports/rp2/rp2_pio.c
+++ b/ports/rp2/rp2_pio.c
@@ -613,7 +613,12 @@ STATIC mp_obj_t rp2_state_machine_exec(mp_obj_t self_in, mp_obj_t instr_in) {
     mp_obj_t rp2_module = mp_import_name(MP_QSTR_rp2, mp_const_none, MP_OBJ_NEW_SMALL_INT(0));
     mp_obj_t asm_pio_encode = mp_load_attr(rp2_module, MP_QSTR_asm_pio_encode);
     uint32_t sideset_count = self->pio->sm[self->sm].pinctrl >> PIO_SM0_PINCTRL_SIDESET_COUNT_LSB;
-    mp_obj_t encoded_obj = mp_call_function_2(asm_pio_encode, instr_in, MP_OBJ_NEW_SMALL_INT(sideset_count));
+    uint8_t sideset_opt = !!(self->pio->sm[self->sm].execctrl & (1 << PIO_SM0_EXECCTRL_SIDE_EN_LSB));
+    mp_obj_t args[3];
+    args[0] = instr_in;
+    args[1] = MP_OBJ_NEW_SMALL_INT(sideset_count);
+    args[2] = MP_OBJ_NEW_SMALL_INT(sideset_opt);
+    mp_obj_t encoded_obj = mp_call_function_n_kw(asm_pio_encode, 3, 0, args);
     mp_int_t encoded = mp_obj_get_int(encoded_obj);
     pio_sm_exec(self->pio, self->sm, encoded);
     return mp_const_none;