stm32f429主频大于160MHz时,sdram数据不稳定

2019-07-20 18:27发布

stm32f429主频为180MHz, sdramz做lcd缓存时,刷完一帧图片,部分像素点颜 {MOD}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]





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麦田稻草
1楼-- · 2019-07-24 06:35
刚打样了stm32f429iit6的板子,回来后测试SDRAM的频率也只能上到85M,新帖在这里:
http://www.openedv.com/posts/list/45430.htm
heitu103
2楼-- · 2019-07-24 11:43
麦田稻草 发表于 2014-12-5 15:37
回复【15楼】heitu103:
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不会吧,我的超频到240M都没问题呀

后来找到问题了 100309o1yi6me2az6ad7m0.png.thumb.jpg
yyx112358
3楼-- · 2019-07-24 12:24
heitu103 发表于 2016-1-29 17:28
后来找到问题了

小白求问,这是什么问题啊?
heitu103
4楼-- · 2019-07-24 18:04
 精彩回答 2  元偷偷看……
jcqi
5楼-- · 2019-07-24 21:37
 精彩回答 2  元偷偷看……
刘仿
6楼-- · 2019-07-24 21:51
可能是电容小啦,过滤高频吧

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