From: Sebastien Bourdeauducq Date: Fri, 27 Jan 2012 13:35:58 +0000 (+0100) Subject: doc: cosmetic changes X-Git-Tag: 24jan2021_ls180~2099^2~1055 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=5466a82933a5e2eee41b55bd171bef9200c24008;p=litex.git doc: cosmetic changes --- diff --git a/doc/asmi.txt b/doc/asmi.txt index a16de956..3eeb51ff 100644 --- a/doc/asmi.txt +++ b/doc/asmi.txt @@ -28,12 +28,11 @@ should be able to peek ahead at the incoming requests and service several of them in parallel, while respecting the various timing specifications of each DRAM bank and avoiding conflicts for the shared data lines. Going further in this direction, a controller able to -complete transfers out of order can provide more performance by: -(1) grouping together requests by DRAM row, in order to minimize time - spent on precharging and activating banks. -(2) grouping together requests by direction (read or write) in order to - minimize delays introduced by bus turnaround and write recovery - times. +complete transfers out of order can provide even more performance by: +(1) grouping requests by DRAM row, in order to minimize time spent on + precharging and activating banks. +(2) grouping requests by direction (read or write) in order to minimize + delays introduced by bus turnaround and write recovery times. (3) being able to complete a request that hits a page earlier than a concurrent one which requires the cycling of another bank. @@ -81,8 +80,8 @@ The data signals are used to complete requests. - DATA_W must supply data to the controller from the appropriate write transaction, on the cycle after they have been called using CALL and TAG_CALL. - - DATA_WM are the byte-granularity write data masks. They are used - in combination with DATA_W to identify the bytes that should be + - DATA_WM are the byte-granular write data masks. They are used in + combination with DATA_W to identify the bytes that should be modified in the memory. The DATA_WM bit should be high for its corresponding DATA_W byte to be written. @@ -112,8 +111,8 @@ STB <0><1><0><0><1><1><0><1><1><0> ACK <0><0><1><0><0><0><1><0><1><1> TAG ------------------ -SDRAM burst width and clock ratios -================================== +SDRAM burst length and clock ratios +=================================== A system using ASMI must set the SDRAM burst length B, the ASMIbus word width W and the ratio between the ASMIbus clock frequency Fa and the SDRAM I/O frequency Fi so that all data transfers last for exactly one