diff --git a/tb/sw/src/main.c b/tb/sw/src/main.c
index 2891ac2..bb25b41 100644
--- a/tb/sw/src/main.c
+++ b/tb/sw/src/main.c
@@ -41,8 +41,9 @@ int main()
 
 	// udelay(50);
 
-	*(cdr_0_tx_txLen) = 32;
+	*(cdr_0_tx_txLen) = 32*4;
 	for( uint8_t i = 0; i < 32; i ++ ){
+		while( (*cdr_0_tx_status & 0x1) );
 		*cdr_0_tx_txFifo = 32-i;
 	}