I inserted in a loop 4 sequential DIG_Block_In() calls to get input data with my AT-DIO-32HS in handshake mode. Before each call the program ensures that the previous transfer was completed, by means of DIG_Block_Check() calls, which indeed automatically call DIG_Block_Clear() at the end. The first call reads a small header (6 shorts) and retrieves how many data the next call should get. The second call reads that amount of data (which can be rather huge, say up to 2 Mbytes, dinamycally allocated). The third call reads a second header and the last call reads another huge block of data. This four operations must be repeated 100 times. What I experience is that the first time the loop is executed everything works fine, but before the second execution (getting next "first" header) the system waits for several seconds (!!). Note that the 4 calls use 4 distinct data buffers. I would avoid using double buffering in this case because my problem is really sequential and can be easily managed in the described way. Any help ?