I have some questions in writing 2D FFT code in MPC5775k by using its SPT
1) Use WIN instruction, failed.
// Transfer input vector by PDMA
// 128 x 64-bit real numbers(32bit real,32 bit image), 64-bit PDMA SRAM word holds 2 input points
// Sign Extension,direct, 24 bit complex pack
// VECTOR_LEN = 128 (128 x 2 input points in each), 128 = 0x0080
// SRAM(input_addr) -> OPRAM (0x8000)
0xA1040080, 0xDEADDEAD, 0x80000000, 0x01000001, // test ,move data from SRAM to SPT OPRAM, ok
// FFT 128 RDX4 instruction w/ complex input
// WIN instruction, multiply a constant complex, here is 2 + 0i;
0x86000080, 0x80009000, 0x00000101, 0x00020000, // WIN failed here
// Stop Cmd
0x10000000, 0x00000000, 0x00000000, 0x00000000,
what I want to do is all the data x 2,but failed, why?
2) SPT is fixed point, when I do 2D FFT, the input data is comlex, and its range is -2^23 to +2^23,
Is SPT capable of doing such FFT? I use the real FFT examples provided by NXP FAE, it supports
input data range is 0 ~ 4096(with left shift, unsigned int)
I have implemented real FFT128/256/512/1024, supported input data range is 0 ~ 4096, but get stuck in complex FFT when input data is very large.
3) Where to find complex FFT example for MPC5775K in this forum?
Any help will be very appreciated..