FSMC异步传输第一次读取的数据为0,后续读取正常是怎么回事?用逻辑分析仪捕获到数据总线上是有正常数据的。
异步传输等待信号在手册中没有详细的介绍,有没有相关的介绍和时序图。
FSMC的配置
RWTiming.FSMC_AddressSetupTime = 0x01;
RWTiming.FSMC_AddressHoldTime = 0x00;
RWTiming.FSMC_DataSetupTime = 0x01;
RWTiming.FSMC_BusTurnAroundDuration = 0x00;
RWTiming.FSMC_CLKDivision = 0x00;
RWTiming.FSMC_DataLatency = 0x00;
RWTiming.FSMC_AccessMode = FSMC_AccessMode_A;
FSMC_NORSRAMInitStructure.FSMC_Bank = FSMC_Bank1_NORSRAM1;
FSMC_NORSRAMInitStructure.FSMC_DataAddressMux = FSMC_DataAddressMux_Enable;
FSMC_NORSRAMInitStructure.FSMC_MemoryType = FSMC_MemoryType_SRAM;
FSMC_NORSRAMInitStructure.FSMC_MemoryDataWidth = FSMC_MemoryDataWidth_16b;
FSMC_NORSRAMInitStructure.FSMC_BurstAccessMode =FSMC_BurstAccessMode_Disable;
FSMC_NORSRAMInitStructure.FSMC_WaitSignalPolarity = FSMC_WaitSignalPolarity_Low;
FSMC_NORSRAMInitStructure.FSMC_AsynchronousWait=FSMC_AsynchronousWait_Enable;
FSMC_NORSRAMInitStructure.FSMC_WrapMode = FSMC_WrapMode_Disable;
FSMC_NORSRAMInitStructure.FSMC_WaitSignalActive = FSMC_WaitSignalActive_BeforeWaitState;
FSMC_NORSRAMInitStructure.FSMC_WriteOperation = FSMC_WriteOperation_Enable;
FSMC_NORSRAMInitStructure.FSMC_WaitSignal = FSMC_WaitSignal_Disable;
FSMC_NORSRAMInitStructure.FSMC_ExtendedMode = FSMC_ExtendedMode_Enable;
FSMC_NORSRAMInitStructure.FSMC_WriteBurst = FSMC_WriteBurst_Disable;
FSMC_NORSRAMInitStructure.FSMC_ReadWriteTimingStruct = &RWTiming;
FSMC_NORSRAMInitStructure.FSMC_WriteTimingStruct = &RWTiming;
FSMC_NORSRAMInit(&FSMC_NORSRAMInitStructure);
FSMC_NORSRAMCmd(FSMC_Bank1_NORSRAM1, ENABLE);
读写的程序
*(vu16*)(FSMC_SRAM_BASE + 0x2) = 0xAA55;
*(vu16*)(FSMC_SRAM_BASE + 0x4) = 0x55AA;
rd16_1 = *(vu16 *)(FSMC_SRAM_BASE + 0x2);
rd16_2 = *(vu16 *)(FSMC_SRAM_BASE + 0x4);
printf("0x%04X\n", rd16_1);
printf("0x%04X\n", rd16_2);
volatile uint16_t *pdat = (volatile uint16_t *)FSMC_SRAM_BASE;
for (int i = 0; i < 1024; i++) {
*pdat = i;
pdat += 2;
}
pdat = (volatile uint16_t *)FSMC_SRAM_BASE;
for (int i = 0; i < 1024; i++) {
rx_buf[i] = *pdat;
pdat += 2;
}
print_buffer(rx_buf, 1024);