diff --git a/bspMCU/bsp_uart.c b/bspMCU/bsp_uart.c
index eb4fc76..f155d7f 100644
--- a/bspMCU/bsp_uart.c
+++ b/bspMCU/bsp_uart.c
@@ -121,6 +121,7 @@ void UART_DMA_RX_IRQHandler(TComCtrl *_ptComCtrl)
             data_len = current_pos - ptUartUserData->m_last_dma_pos;
             if (data_len > 0) 
             {
+                SCB_InvalidateDCache_by_Addr((uint32_t*)&ptUartUserData->m_dma_rx_buf[ptUartUserData->m_last_dma_pos], data_len);
                 rd_ComRecvProc(_ptComCtrl, (const char*)&ptUartUserData->m_dma_rx_buf[ptUartUserData->m_last_dma_pos], data_len);
             }
         } 
@@ -133,10 +134,12 @@ void UART_DMA_RX_IRQHandler(TComCtrl *_ptComCtrl)
             
             if (part1 > 0) 
             {
+                SCB_InvalidateDCache_by_Addr((uint32_t*)&ptUartUserData->m_dma_rx_buf[ptUartUserData->m_last_dma_pos], part1);
                 rd_ComRecvProc(_ptComCtrl, (const char*)&ptUartUserData->m_dma_rx_buf[ptUartUserData->m_last_dma_pos], part1);
             }
             if (part2 > 0) 
             {
+                SCB_InvalidateDCache_by_Addr((uint32_t*)&ptUartUserData->m_dma_rx_buf[0], part2);
                 rd_ComRecvProc(_ptComCtrl, (const char*)&ptUartUserData->m_dma_rx_buf[0], part2);
             }
         }
diff --git a/library/ringbuffer/include/ringbuffer.h b/library/ringbuffer/include/ringbuffer.h
index d07a246..813bdba 100644
--- a/library/ringbuffer/include/ringbuffer.h
+++ b/library/ringbuffer/include/ringbuffer.h
@@ -118,6 +118,7 @@ extern int rd_RingbufferGet(rd_ringbuf_t *rb, char *ptr, int length);
 extern int rd_RingbufferGetchar(rd_ringbuf_t *rb, char *ch);
 extern void rd_RingbufferInit(rd_ringbuf_t *rb, char *pool, int size);
 extern int rd_RingbufferPeak(rd_ringbuf_t *rb, char **ptr);
+extern int rd_RingbufferPeekLinear(rd_ringbuf_t *rb, char *out, int length);
 extern int rd_RingbufferPut(rd_ringbuf_t *rb, const char *ptr, int length);
 extern int rd_RingbufferPutchar(rd_ringbuf_t *rb, const char ch);
 extern int rd_RingbufferPutcharForce(rd_ringbuf_t *rb, const char ch);
diff --git a/library/ringbuffer/ringbuffer.c b/library/ringbuffer/ringbuffer.c
index 8628457..f8ac6fb 100644
--- a/library/ringbuffer/ringbuffer.c
+++ b/library/ringbuffer/ringbuffer.c
@@ -249,6 +249,34 @@ int rd_RingbufferPeak(rd_ringbuf_t *rb, char **ptr)
     return avail;
 }
 
+/**
+ * @brief Peek data from the ring buffer into a linear buffer without consuming.
+ *
+ * @param rb        A pointer to the ring buffer object.
+ * @param out       A pointer to the output buffer to fill.
+ * @param length    Maximum number of bytes to peek.
+ *
+ * @return Return the number of bytes actually copied.
+ */
+int rd_RingbufferPeekLinear(rd_ringbuf_t *rb, char *out, int length)
+{
+    if (!rb || !out || length <= 0) return RD_INVALUE;
+
+    int avail = rd_RingbufferDataLen(rb);
+    if (avail == 0) return 0;
+    if (length > avail) length = avail;
+
+    unsigned short ri = ATOMIC_LOAD(&rb->m_sReadIndex, unsigned short, ATOMIC_ORDER_RELAXED);
+    if (rb->m_iBufsize - ri >= length) {
+        RD_MEMCPY(out, &rb->m_pcBufPtr[ri], length);
+    } else {
+        int first = rb->m_iBufsize - ri;
+        RD_MEMCPY(out, &rb->m_pcBufPtr[ri], first);
+        RD_MEMCPY(out + first, &rb->m_pcBufPtr[0], length - first);
+    }
+    return length;
+}
+
 /**
  * @brief Put a byte into the ring buffer. If ring buffer is full, this operation will fail.
  *
diff --git a/peripheral/com.c b/peripheral/com.c
index 911299b..fc6ee26 100644
--- a/peripheral/com.c
+++ b/peripheral/com.c
@@ -229,6 +229,8 @@ int rd_ComRead(TComCtrl *_ptComCtrl, char *_pBuffer, uint32_t _iSize)
 
     char *pPeakData = NULL;
     int iPeakLen = rd_RingbufferPeak(_ptComCtrl->m_stComBuf.m_ptRecv, &pPeakData);
+    char cPeekBuf[512];
+    int iPeekLenLinear = rd_RingbufferPeekLinear(_ptComCtrl->m_stComBuf.m_ptRecv, cPeekBuf, sizeof(cPeekBuf));
 
     if (iPeakLen < 0) 
     {
@@ -238,6 +240,7 @@ int rd_ComRead(TComCtrl *_ptComCtrl, char *_pBuffer, uint32_t _iSize)
     {
         Rd_SemWait(&_ptComCtrl->m_stComBuf.m_sem_Recv, __func__, NULL);
         iPeakLen = rd_RingbufferPeak(_ptComCtrl->m_stComBuf.m_ptRecv, &pPeakData);
+        iPeekLenLinear = rd_RingbufferPeekLinear(_ptComCtrl->m_stComBuf.m_ptRecv, cPeekBuf, sizeof(cPeekBuf));
 
         if (iPeakLen < 0)
         {
@@ -269,7 +272,7 @@ int rd_ComRead(TComCtrl *_ptComCtrl, char *_pBuffer, uint32_t _iSize)
             iPackLen = 1;
             if (NULL != ptMutiDev->m_pfCheck)
             {
-                iPackLen = ptMutiDev->m_pfCheck(pPeakData, iPeakLen);
+                iPackLen = ptMutiDev->m_pfCheck(cPeekBuf, iPeekLenLinear);
             }
 
             if (iPackLen > 0)
@@ -341,7 +344,7 @@ int rd_ComRead(TComCtrl *_ptComCtrl, char *_pBuffer, uint32_t _iSize)
             iPackLen = 1;
             if (NULL != ptMutiDev->m_pfCheck) 
             {
-                iPackLen = ptMutiDev->m_pfCheck(pPeakData, iPeakLen);
+                iPackLen = ptMutiDev->m_pfCheck(cPeekBuf, iPeekLenLinear);
             }
         }