diff --git a/BLEh.c b/BLEh.c
index 1036e36..2824e08 100644
--- a/BLEh.c
+++ b/BLEh.c
@@ -128,6 +128,23 @@ void ble_advertise(void){
   ESP_ERROR_CHECK(ble_gap_adv_start(BLE_OWN_ADDR_PUBLIC, NULL, BLE_HS_FOREVER, &adv_params, ble_gap_event, NULL));
 }
 
+int gatt_svr_chr_write_get_data(struct os_mbuf *om, uint16_t min_len, uint16_t max_len, void *dst, uint16_t *len){
+    uint16_t om_len;
+    int rc;
+
+    om_len = OS_MBUF_PKTLEN(om);
+    if (om_len < min_len || om_len > max_len) {
+        return BLE_ATT_ERR_INVALID_ATTR_VALUE_LEN;
+    }
+
+    rc = ble_hs_mbuf_to_flat(om, dst, max_len, len);
+    if (rc != 0) {
+        return BLE_ATT_ERR_UNLIKELY;
+    }
+
+    return 0;
+}
+
 static int char_access_handler(uint16_t conn_handle, uint16_t attr_handle, struct ble_gatt_access_ctxt* ctxt, void* arg){
   int rc = 0;
 
@@ -145,6 +162,12 @@ static int char_access_handler(uint16_t conn_handle, uint16_t attr_handle, struc
       on_char_read_callback(svc_ind, chr_ind, &value, &value_size);
       rc = os_mbuf_append(ctxt->om, value, value_size);
     break;
+    case BLE_GATT_ACCESS_OP_WRITE_CHR:
+      ;
+      if(on_char_write_callback == NULL) return 0;
+      rc = on_char_write_callback(svc_ind, chr_ind, ctxt->om);
+    break;
+
     case BLE_GATT_ACCESS_OP_READ_DSC:
       ;
       struct dsc_content* content = (struct dsc_content*)ctxt->dsc->arg;
@@ -155,9 +178,12 @@ static int char_access_handler(uint16_t conn_handle, uint16_t attr_handle, struc
   return rc ? BLE_ATT_ERR_INSUFFICIENT_RES : 0;
 }
 
-void add_on_char_read_handler(charReadCallback cb){
+void set_on_char_read_handler(charReadCallback cb){
   on_char_read_callback = cb;
 }
+void set_on_char_write_handler(charWriteCallback cb){
+  on_char_write_callback = cb;
+}
 
 void set_gatt_services(struct ble_gatt_svc_def* svcs, uint16_t num){
   gatt_svr_svcs = svcs;
diff --git a/include/BLEh.h b/include/BLEh.h
index f8c32b2..33f350e 100644
--- a/include/BLEh.h
+++ b/include/BLEh.h
@@ -21,7 +21,7 @@ struct dsc_content {
 };
 
 typedef void (*charReadCallback)(int svc_ind, int chr_ind, void** value, size_t* value_size);
-typedef void (*charWriteCallback)(int svc_ind, int chr_ind, void* value, size_t value_size);
+typedef int (*charWriteCallback)(int svc_ind, int chr_ind, struct os_mbuf* om);
 typedef void (*dscReadCallback)(int svc_ind, int chr_ind, void** value, size_t* value_size);
 
 void initBLE(char* name);
@@ -29,4 +29,6 @@ void ble_advertise(void);
 void set_gatt_services(struct ble_gatt_svc_def* svcs, uint16_t num);
 void print_service(struct ble_gatt_svc_def* svcs);
 void notify(uint16_t svc_ind, uint16_t chr_ind, void* value, size_t value_size);
-void add_on_char_read_handler(charReadCallback cb);
+void set_on_char_read_handler(charReadCallback cb);
+void set_on_char_write_handler(charWriteCallback cb);
+int gatt_svr_chr_write_get_data(struct os_mbuf *om, uint16_t min_len, uint16_t max_len, void *dst, uint16_t *len);
\ No newline at end of file