From 491d3a77cfe90b21c83304a2d4a5af54c909c916 Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Fri, 1 Nov 2013 11:56:23 -0400 Subject: [PATCH] mem: Less conservative tRAS in DRAM configurations This patch changes the default values of the tRAS timing parameter to be less conservative, and closer in line with existing parts. --- src/mem/SimpleDRAM.py | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/src/mem/SimpleDRAM.py b/src/mem/SimpleDRAM.py index f75860dce..8de210641 100644 --- a/src/mem/SimpleDRAM.py +++ b/src/mem/SimpleDRAM.py @@ -168,11 +168,11 @@ class DDR3_1600_x64(SimpleDRAM): # DDR3 has 8 banks in all configurations banks_per_rank = 8 - # DDR3-1600 11-11-11 + # DDR3-1600 11-11-11-28 tRCD = '13.75ns' tCL = '13.75ns' tRP = '13.75ns' - tRAS = '41.25ns' + tRAS = '35ns' # 8 beats across an x64 interface translates to 4 clocks @ 800 MHz. # Note this is a BL8 DDR device. @@ -224,7 +224,7 @@ class LPDDR2_S4_1066_x32(SimpleDRAM): # Pre-charge one bank 15 ns (all banks 18 ns) tRP = '15ns' - tRAS = '45ns' + tRAS = '42ns' # 8 beats across an x32 DDR interface translates to 4 clocks @ 533 MHz. # Note this is a BL8 DDR device. @@ -269,7 +269,7 @@ class WideIO_200_x128(SimpleDRAM): tRCD = '18ns' tCL = '18ns' tRP = '18ns' - tRAS = '54ns' + tRAS = '42ns' # 4 beats across an x128 SDR interface translates to 4 clocks @ 200 MHz. # Note this is a BL4 SDR device. @@ -317,7 +317,7 @@ class LPDDR3_1600_x32(SimpleDRAM): # 12 CK read latency, 6 CK write latency @ 800 MHz, 1.25 ns cycle time tCL = '15ns' - tRAS = '45ns' + tRAS = '42ns' # Pre-charge one bank 15 ns (all banks 18 ns) tRP = '15ns' -- 2.30.2