From 4f387c8ff0571deedc86dc459e94e555b9768282 Mon Sep 17 00:00:00 2001 From: Wade Fife Date: Mon, 10 Aug 2020 09:31:26 -0500 Subject: fpga: lib: Change max FFT size to 1024 The max FFT size was 4096, but we don't currently have any devices that can do that without modification. This is because, currently, the FFT size must be the same as the packet size, and the largest packet size supported by most devices is about 8000 bytes, or 2000 sc16 samples. Therefore, the largest FFT size supported without modifying other code is 1024 samples. This change frees up about 21% of the LUTs and 36% of the BRAM used by axi_fft and makes the software block controller and the IP agree on the maximum FFT size. --- host/lib/rfnoc/fft_block_control.cpp | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'host/lib/rfnoc') diff --git a/host/lib/rfnoc/fft_block_control.cpp b/host/lib/rfnoc/fft_block_control.cpp index 867d458ca..23ee380ac 100644 --- a/host/lib/rfnoc/fft_block_control.cpp +++ b/host/lib/rfnoc/fft_block_control.cpp @@ -22,7 +22,7 @@ constexpr int DEFAULT_FFT_SCALING = 1706; // Conservative 1/N scaling // FFT IP constraints constexpr int MIN_FFT_LENGTH = 8; -constexpr int MAX_FFT_LENGTH = 2048; +constexpr int MAX_FFT_LENGTH = 1024; const uhd::rfnoc::io_type_t DEFAULT_TYPE = uhd::rfnoc::IO_TYPE_SC16; -- cgit v1.2.3