diff --git a/src/libboard_artiq/src/cxp_proto.rs b/src/libboard_artiq/src/cxp_proto.rs
index de1e39f..604e5ca 100644
--- a/src/libboard_artiq/src/cxp_proto.rs
+++ b/src/libboard_artiq/src/cxp_proto.rs
@@ -85,45 +85,55 @@ pub enum DownConnPacket {
     },
 }
 
-fn capture_ctrl_packet(reader: &mut Cursor<&mut [u8]>, with_tag: bool) -> Result<DownConnPacket, Error> {
-    let mut tag: Option<u8> = None;
-    if with_tag {
-        tag = Some(reader.read_4x_u8()?);
+impl DownConnPacket {
+    pub fn read_from(reader: &mut Cursor<&mut [u8]>, packet_type: u8) -> Result<Self, Error> {
+        match packet_type {
+            0x03 => DownConnPacket::get_ctrl_packet(reader, false),
+            0x06 => DownConnPacket::get_ctrl_packet(reader, true),
+            _ => Err(Error::UnknownPacket(packet_type)),
+        }
     }
 
-    let ackcode = reader.read_4x_u8()?;
-
-    match ackcode {
-        0x00 => {
-            let length = reader.read_u32()?;
-            let mut data: [u8; DATA_MAXSIZE] = [0; DATA_MAXSIZE];
-            reader.read(&mut data[0..length as usize])?;
-
-            let checksum = get_cxp_crc(&reader.get_ref()[0..reader.position()]);
-            let recv_checksum = reader.read_u32()?;
-            println!("calculated checksum = {:#010X}", checksum);
-            println!("read checksum = {:#010X}", recv_checksum);
-            if recv_checksum != checksum {
-                return Err(Error::CorruptedPacket);
-            }
-            return Ok(DownConnPacket::CtrlReply { tag, length, data });
+    fn get_ctrl_packet(reader: &mut Cursor<&mut [u8]>, with_tag: bool) -> Result<Self, Error> {
+        let mut tag: Option<u8> = None;
+        if with_tag {
+            tag = Some(reader.read_4x_u8()?);
         }
-        0x01 => return Ok(DownConnPacket::CtrlAck { tag }),
-        0x04 => {
-            let length = reader.read_u32()?;
-            let mut time: [u8; DATA_MAXSIZE] = [0; DATA_MAXSIZE];
-            reader.read(&mut time[0..length as usize])?;
 
-            let checksum = get_cxp_crc(&reader.get_ref()[0..reader.position()]);
-            let recv_checksum = reader.read_u32()?;
-            println!("calculated checksum = {:#010X}", checksum);
-            println!("read checksum = {:#010X}", recv_checksum);
-            if recv_checksum != checksum {
-                return Err(Error::CorruptedPacket);
+        let ackcode = reader.read_4x_u8()?;
+
+        match ackcode {
+            0x00 => {
+                let length = reader.read_u32()?;
+                let mut data: [u8; DATA_MAXSIZE] = [0; DATA_MAXSIZE];
+                reader.read(&mut data[0..length as usize])?;
+
+                let checksum = get_cxp_crc(&reader.get_ref()[0..reader.position()]);
+                let recv_checksum = reader.read_u32()?;
+                println!("calculated checksum = {:#010X}", checksum);
+                println!("read checksum = {:#010X}", recv_checksum);
+                if recv_checksum != checksum {
+                    return Err(Error::CorruptedPacket);
+                }
+                return Ok(DownConnPacket::CtrlReply { tag, length, data });
             }
-            return Ok(DownConnPacket::CtrlDelay { tag, length, time });
+            0x01 => return Ok(DownConnPacket::CtrlAck { tag }),
+            0x04 => {
+                let length = reader.read_u32()?;
+                let mut time: [u8; DATA_MAXSIZE] = [0; DATA_MAXSIZE];
+                reader.read(&mut time[0..length as usize])?;
+
+                let checksum = get_cxp_crc(&reader.get_ref()[0..reader.position()]);
+                let recv_checksum = reader.read_u32()?;
+                println!("calculated checksum = {:#010X}", checksum);
+                println!("read checksum = {:#010X}", recv_checksum);
+                if recv_checksum != checksum {
+                    return Err(Error::CorruptedPacket);
+                }
+                return Ok(DownConnPacket::CtrlDelay { tag, length, time });
+            }
+            _ => return Err(Error::CtrlAckError(ackcode)),
         }
-        _ => return Err(Error::CtrlAckError(ackcode)),
     }
 }
 
@@ -133,11 +143,8 @@ pub fn receive(channel: usize) -> Result<(), Error> {
         let mut reader = Cursor::new(slice::from_raw_parts_mut(ptr as *mut u8, MEM_LEN));
         let packet_type = (CXP[channel].downconn_packet_type_read)();
 
-        let packet = match packet_type {
-            0x03 => capture_ctrl_packet(&mut reader, false),
-            0x06 => capture_ctrl_packet(&mut reader, true),
-            _ => return Err(Error::UnknownPacket(packet_type)),
-        };
+        let packet = DownConnPacket::read_from(&mut reader, packet_type);
+
         println!("{:?}", packet);
     }
     Ok(())
@@ -190,7 +197,6 @@ pub enum UpConnPacket {
 
 impl UpConnPacket {
     pub fn write_to(&self, writer: &mut Cursor<&mut [u8]>) -> Result<(), Error> {
-        // CoaXpress use big endian
         match *self {
             UpConnPacket::CtrlRead { tag, addr, length } => {
                 match tag {