It is customary that the X space contains stationary arrays, e.g. digital filter coefficients, FFT blocks, etc, whereas the Y space contains dynamic arrays, e.g. samples of the signal being processed or similar. For this reason it was made possible that one section of he program memory is mapped as X space. This means that the coefficients of a digital filter may be saved in the program memory as constants, that this section of the program memory is declared an extention of the X space and that it is accessible as if it was in the data memory. Of course, the addresses of these elements will not be the same as in the program memory, but they will start from the address 0x8000, as can be seen in Fig. 11-2. In this way an additional capacity for saving coefficients has been obtained which is essential particularly for high order filters, FFT algorithms and many other applications. This procedure is known as Program Space Visibility (PSV) Management.Address generation in PSV management is shown in Fig. 11-3.