diff --git a/package/ctypes/ctypes.c b/package/ctypes/ctypes.c
index 732b001f9..d75cfb349 100644
--- a/package/ctypes/ctypes.c
+++ b/package/ctypes/ctypes.c
@@ -1,7 +1,7 @@
 #include "ctypes_Test.h"
+#include "ctypes_c_float.h"
 #include "ctypes_c_uint.h"
 #include "ctypes_c_wchar_p.h"
-#include "ctypes_c_float.h"
 #include "ctypes_utils.h"
 
 void ctypes_c_uint___init__(PikaObj* self, int value) {
@@ -12,7 +12,7 @@ void ctypes_c_wchar_p___init__(PikaObj* self, char* value) {
     ctypesUtils_setStr(self, value);
 }
 
-void ctypes_c_float___init__(PikaObj *self, float value){
+void ctypes_c_float___init__(PikaObj* self, float value) {
     ctypesUtils_setFloat(self, value);
 }
 
@@ -27,6 +27,18 @@ int ctypes_Test_dc_cpuapdu_hex(PikaObj* self,
                                int slen) {
     printf("input: slen = %d, sendbuf = %s\n", slen, sendbuf);
     ctypesUtils_setInt(rlen, 5);
-    ctypesUtils_setStr(rcvbuf, "testout");
+    char rcv[] = {0x01, 0x02, 0x03, 0x00, 0x05, 0x08};
+    ctypesUtils_setMem(rcvbuf, rcv, sizeof(rcv));
     return 0;
 }
+
+void ctypes_Test_print_rcv(PikaObj* self, PikaObj* rcvbuf) {
+    char* rcv = ctypesUtils_getMem(rcvbuf);
+    size_t rcv_size = ctypesUtils_getMemSize(rcvbuf);
+    __platform_printf("{");
+    for (size_t i = 0; i < rcv_size - 1; i++) {
+        __platform_printf("%x, ", rcv[i]);
+    }
+    __platform_printf("%x", rcv[rcv_size - 1]);
+    __platform_printf("}\r\n");
+}
diff --git a/package/ctypes/ctypes.py b/package/ctypes/ctypes.py
index ad73133ca..d6fbacaf4 100644
--- a/package/ctypes/ctypes.py
+++ b/package/ctypes/ctypes.py
@@ -32,3 +32,4 @@ class c_longdouble(c_float):...
 class Test(TinyObj):
     def add(self, c_uint1:c_uint, c_uint2:c_uint)->int:...
     def dc_cpuapdu_hex(self, slen:int, sendbuf:str, rlen:c_uint, rcvbuf:c_char_p) -> int:...
+    def print_rcv(self, rcvbuf: c_char_p):...
diff --git a/port/linux/package/pikascript/ctypes.py b/port/linux/package/pikascript/ctypes.py
index ad73133ca..d6fbacaf4 100644
--- a/port/linux/package/pikascript/ctypes.py
+++ b/port/linux/package/pikascript/ctypes.py
@@ -32,3 +32,4 @@ class c_longdouble(c_float):...
 class Test(TinyObj):
     def add(self, c_uint1:c_uint, c_uint2:c_uint)->int:...
     def dc_cpuapdu_hex(self, slen:int, sendbuf:str, rlen:c_uint, rcvbuf:c_char_p) -> int:...
+    def print_rcv(self, rcvbuf: c_char_p):...
diff --git a/port/linux/package/pikascript/pikascript-lib/ctypes/ctypes.c b/port/linux/package/pikascript/pikascript-lib/ctypes/ctypes.c
index 732b001f9..d75cfb349 100644
--- a/port/linux/package/pikascript/pikascript-lib/ctypes/ctypes.c
+++ b/port/linux/package/pikascript/pikascript-lib/ctypes/ctypes.c
@@ -1,7 +1,7 @@
 #include "ctypes_Test.h"
+#include "ctypes_c_float.h"
 #include "ctypes_c_uint.h"
 #include "ctypes_c_wchar_p.h"
-#include "ctypes_c_float.h"
 #include "ctypes_utils.h"
 
 void ctypes_c_uint___init__(PikaObj* self, int value) {
@@ -12,7 +12,7 @@ void ctypes_c_wchar_p___init__(PikaObj* self, char* value) {
     ctypesUtils_setStr(self, value);
 }
 
-void ctypes_c_float___init__(PikaObj *self, float value){
+void ctypes_c_float___init__(PikaObj* self, float value) {
     ctypesUtils_setFloat(self, value);
 }
 
@@ -27,6 +27,18 @@ int ctypes_Test_dc_cpuapdu_hex(PikaObj* self,
                                int slen) {
     printf("input: slen = %d, sendbuf = %s\n", slen, sendbuf);
     ctypesUtils_setInt(rlen, 5);
-    ctypesUtils_setStr(rcvbuf, "testout");
+    char rcv[] = {0x01, 0x02, 0x03, 0x00, 0x05, 0x08};
+    ctypesUtils_setMem(rcvbuf, rcv, sizeof(rcv));
     return 0;
 }
+
+void ctypes_Test_print_rcv(PikaObj* self, PikaObj* rcvbuf) {
+    char* rcv = ctypesUtils_getMem(rcvbuf);
+    size_t rcv_size = ctypesUtils_getMemSize(rcvbuf);
+    __platform_printf("{");
+    for (size_t i = 0; i < rcv_size - 1; i++) {
+        __platform_printf("%x, ", rcv[i]);
+    }
+    __platform_printf("%x", rcv[rcv_size - 1]);
+    __platform_printf("}\r\n");
+}