stm32f429主频为180MHz, sdramz做lcd缓存时,刷完一帧图片，部分像素点颜色发送了变化，如下图。但将主频设置为160MHz时图片显示又很稳定，后来测试了一下sdram，发现主频大于160M,并且随着主频的增大，sdram的数据越不稳定。而160M时数据又很稳定，有没有人遇到这样的问题呢？会不会是sdram的布线不好引起的？

sdram配置如下：

[mw_shl_code=c,true]/* FMC SDRAM Bank configuration */

/* Timing configuration for 90 Mhz of SD clock frequency (180Mhz/2) */

/* TMRD: 2 Clock cycles */

FMC_SDRAMTimingInitStructure.FMC_LoadToActiveDelay = 2;

/* TXSR: min=70ns (7x11.11ns) */

FMC_SDRAMTimingInitStructure.FMC_ExitSelfRefreshDelay = 7;

/* TRAS: min=42ns (4x11.11ns) max=120k (ns) */

FMC_SDRAMTimingInitStructure.FMC_SelfRefreshTime = 4;

/* TRC: min=70 (7x11.11ns) */

FMC_SDRAMTimingInitStructure.FMC_RowCycleDelay = 7;

/* TWR: min=1+ 7ns (1+1x11.11ns) */

FMC_SDRAMTimingInitStructure.FMC_WriteRecoveryTime = 2;

/* TRP: 20ns => 2x11.11ns */

FMC_SDRAMTimingInitStructure.FMC_RPDelay = 2;

/* TRCD: 20ns => 2x11.11ns */

FMC_SDRAMTimingInitStructure.FMC_RCDDelay = 2;

/* FMC SDRAM control configuration */

FMC_SDRAMInitStructure.FMC_Bank = FMC_Bank2_SDRAM;

/* Row addressing: [7:0] */

FMC_SDRAMInitStructure.FMC_ColumnBitsNumber = FMC_ColumnBits_Number_8b;

/* Column addressing: [11:0] */

FMC_SDRAMInitStructure.FMC_RowBitsNumber = FMC_RowBits_Number_12b;

FMC_SDRAMInitStructure.FMC_SDMemoryDataWidth = SDRAM_MEMORY_WIDTH;

FMC_SDRAMInitStructure.FMC_InternalBankNumber = FMC_InternalBank_Number_4;

FMC_SDRAMInitStructure.FMC_CASLatency = SDRAM_CAS_LATENCY;

FMC_SDRAMInitStructure.FMC_WriteProtection = FMC_Write_Protection_Disable;

FMC_SDRAMInitStructure.FMC_SDClockPeriod = SDCLOCK_PERIOD;

FMC_SDRAMInitStructure.FMC_ReadBurst = SDRAM_READBURST;

FMC_SDRAMInitStructure.FMC_ReadPipeDelay = FMC_ReadPipe_Delay_1;

FMC_SDRAMInitStructure.FMC_SDRAMTimingStruct = &FMC_SDRAMTimingInitStructure;[/mw_shl_code]

bd1fa35bcce5b69d939ec48de2ffbbe3_15.jpg (0 Bytes, 下载次数: 15)

2010-12-14 22:54 上传