check display-bus transaction status and act accordingly

1 files changed, 6 insertions, 1 deletions

diff --git a/shared-bindings/displayio/ParallelBus.c b/shared-bindings/displayio/ParallelBus.c
index a54a84471..6a499ed06 100644
--- a/shared-bindings/displayio/ParallelBus.c
+++ b/shared-bindings/displayio/ParallelBus.c
@@ -114,7 +114,12 @@ STATIC mp_obj_t displayio_parallelbus_obj_send(mp_obj_t self, mp_obj_t command_o
     mp_buffer_info_t bufinfo;
     mp_get_buffer_raise(data_obj, &bufinfo, MP_BUFFER_READ);
 
-    common_hal_displayio_parallelbus_begin_transaction(self);
+    // Wait for display bus to be available.
+    while (!common_hal_displayio_parallelbus_begin_transaction(self)) {
+#ifdef MICROPY_VM_HOOK_LOOP
+        MICROPY_VM_HOOK_LOOP ;
+#endif
+    }
     common_hal_displayio_parallelbus_send(self, true, &command, 1);
     common_hal_displayio_parallelbus_send(self, false, ((uint8_t*) bufinfo.buf), bufinfo.len);
     common_hal_displayio_parallelbus_end_transaction(self);