diff --git a/include/fw_spi.h b/include/fw_spi.h
index a4dee18..3491df1 100644
--- a/include/fw_spi.h
+++ b/include/fw_spi.h
@@ -43,9 +43,10 @@ typedef enum
     SPI_ClockPreScaler_32or2   = 0x03,
 } SPI_ClockPreScaler_t;
 
-#define SPI_RxTxFinished()                  (SPSTAT & (0x01 << 7))
-#define SPI_ClearInterrupt()                SFR_RESET(SPSTAT, 7)
-#define SPI_ClearWriteConflictInterrupt()   SFR_RESET(SPSTAT, 6)
+#define SPI_RxTxFinished()                  (SPSTAT & 0x80)
+#define SPI_ClearInterrupt()                SFR_SET(SPSTAT, 7)
+#define SPI_ClearWriteConflictInterrupt()   SFR_SET(SPSTAT, 6)
+#define SPI_ClearInterrupts()               (SPSTAT |= 0xC0)
 
 #define SPI_IgnoreSlaveSelect(__STATE__)    SFR_ASSIGN(SPCTL, 7, __STATE__)
 #define SPI_SetEnableState(__STATE__)       SFR_ASSIGN(SPCTL, 6, __STATE__)
@@ -64,4 +65,6 @@ typedef enum
 */
 #define SPI_SwitchPort(__ALTER_PORT__)    (P_SW1 = P_SW1 & ~(0x03 << 2) | ((__ALTER_PORT__) << 2))
 
+uint8_t SPI_TxRx(uint8_t dat);
+
 #endif
diff --git a/src/fw_spi.c b/src/fw_spi.c
new file mode 100644
index 0000000..88ab700
--- /dev/null
+++ b/src/fw_spi.c
@@ -0,0 +1,27 @@
+// Copyright 2021 IOsetting <iosetting(at)outlook.com>
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "fw_spi.h"
+#include "fw_tim.h"
+#include "fw_sys.h"
+
+
+uint8_t SPI_TxRx(uint8_t dat)
+{
+    SPI_ClearInterrupts();
+	SPDAT = dat;
+    while (!SPI_RxTxFinished());
+    SPI_ClearInterrupts();
+	return SPDAT;
+}