NXP技术支持：
您好！
以下是NXP官方RT1052的SDK中的.ini文件中的SDRAM初始化部分：
FUNC void _sdr_Init(void)
{
// Config IOMUX
_WDWORD(0x401F8014, 0x00000000);
_WDWORD(0x401F8018, 0x00000000);
_WDWORD(0x401F801C, 0x00000000);
_WDWORD(0x401F8020, 0x00000000);
_WDWORD(0x401F8024, 0x00000000);
_WDWORD(0x401F8028, 0x00000000);
_WDWORD(0x401F802C, 0x00000000);
_WDWORD(0x401F8030, 0x00000000);
_WDWORD(0x401F8034, 0x00000000);
_WDWORD(0x401F8038, 0x00000000);
_WDWORD(0x401F803C, 0x00000000);
_WDWORD(0x401F8040, 0x00000000);
_WDWORD(0x401F8044, 0x00000000);
_WDWORD(0x401F8048, 0x00000000);
_WDWORD(0x401F804C, 0x00000000);
_WDWORD(0x401F8050, 0x00000000);
_WDWORD(0x401F8054, 0x00000000);
_WDWORD(0x401F8058, 0x00000000);
_WDWORD(0x401F805C, 0x00000000);
_WDWORD(0x401F8060, 0x00000000);
_WDWORD(0x401F8064, 0x00000000);
_WDWORD(0x401F8068, 0x00000000);
_WDWORD(0x401F806C, 0x00000000);
_WDWORD(0x401F8070, 0x00000000);
_WDWORD(0x401F8074, 0x00000000);
_WDWORD(0x401F8078, 0x00000000);
_WDWORD(0x401F807C, 0x00000000);
_WDWORD(0x401F8080, 0x00000000);
_WDWORD(0x401F8084, 0x00000000);
_WDWORD(0x401F8088, 0x00000000);
_WDWORD(0x401F808C, 0x00000000);
_WDWORD(0x401F8090, 0x00000000);
_WDWORD(0x401F8094, 0x00000000);
_WDWORD(0x401F8098, 0x00000000);
_WDWORD(0x401F809C, 0x00000000);
_WDWORD(0x401F80A0, 0x00000000);
_WDWORD(0x401F80A4, 0x00000000);
_WDWORD(0x401F80A8, 0x00000000);
_WDWORD(0x401F80AC, 0x00000000);
_WDWORD(0x401F80B0, 0x00000010); // EMC_39, DQS PIN, enable SION
// PAD ctrl
// drive strength = 0x7 to increase drive strength
// otherwise the data7 bit may fail.
_WDWORD(0x401F8204, 0x000110F9);
_WDWORD(0x401F8208, 0x000110F9);
_WDWORD(0x401F820C, 0x000110F9);
_WDWORD(0x401F8210, 0x000110F9);
_WDWORD(0x401F8214, 0x000110F9);
_WDWORD(0x401F8218, 0x000110F9);
_WDWORD(0x401F821C, 0x000110F9);
_WDWORD(0x401F8220, 0x000110F9);
_WDWORD(0x401F8224, 0x000110F9);
_WDWORD(0x401F8228, 0x000110F9);
_WDWORD(0x401F822C, 0x000110F9);
_WDWORD(0x401F8230, 0x000110F9);
_WDWORD(0x401F8234, 0x000110F9);
_WDWORD(0x401F8238, 0x000110F9);
_WDWORD(0x401F823C, 0x000110F9);
_WDWORD(0x401F8240, 0x000110F9);
_WDWORD(0x401F8244, 0x000110F9);
_WDWORD(0x401F8248, 0x000110F9);
_WDWORD(0x401F824C, 0x000110F9);
_WDWORD(0x401F8250, 0x000110F9);
_WDWORD(0x401F8254, 0x000110F9);
_WDWORD(0x401F8258, 0x000110F9);
_WDWORD(0x401F825C, 0x000110F9);
_WDWORD(0x401F8260, 0x000110F9);
_WDWORD(0x401F8264, 0x000110F9);
_WDWORD(0x401F8268, 0x000110F9);
_WDWORD(0x401F826C, 0x000110F9);
_WDWORD(0x401F8270, 0x000110F9);
_WDWORD(0x401F8274, 0x000110F9);
_WDWORD(0x401F8278, 0x000110F9);
_WDWORD(0x401F827C, 0x000110F9);
_WDWORD(0x401F8280, 0x000110F9);
_WDWORD(0x401F8284, 0x000110F9);
_WDWORD(0x401F8288, 0x000110F9);
_WDWORD(0x401F828C, 0x000110F9);
_WDWORD(0x401F8290, 0x000110F9);
_WDWORD(0x401F8294, 0x000110F9);
_WDWORD(0x401F8298, 0x000110F9);
_WDWORD(0x401F829C, 0x000110F9);
_WDWORD(0x401F82A0, 0x000110F9);
// Config SDR Controller Registers/
_WDWORD(0x402F0000,0x10000004); // MCR
_WDWORD(0x402F0008,0x00000081); // BMCR0
_WDWORD(0x402F000C,0x00000081); // BMCR1
_WDWORD(0x402F0010,0x8000001B); // BR0, 32MB
_WDWORD(0x402F0040,0x00000F07); // SDRAMCR0
_WDWORD(0x402F0044,0x00652922); // SDRAMCR1
_WDWORD(0x402F0048,0x00010920); // SDRAMCR2
_WDWORD(0x402F004C,0x50210A08); // SDRAMCR3
_WDWORD(0x402F0090,0x80000000); // IPCR0
_WDWORD(0x402F0094,0x00000002); // IPCR1
_WDWORD(0x402F0098,0x00000000); // IPCR2
_WDWORD(0x402F009C,0xA55A000F); // IPCMD, SD_CC_IPREA
SDRAM_WaitIpCmdDone();
_WDWORD(0x402F009C,0xA55A000C); // SD_CC_IAF
SDRAM_WaitIpCmdDone();
_WDWORD(0x402F009C,0xA55A000C); // SD_CC_IAF
SDRAM_WaitIpCmdDone();
_WDWORD(0x402F00A0,0x00000030); // IPTXDAT
_WDWORD(0x402F009C,0xA55A000A); // SD_CC_IMS
SDRAM_WaitIpCmdDone();
_WDWORD(0x402F004C,0x08080A01 ); // enable sdram self refresh again after initialization done.
}
我查了官方的RM（参考手册），然后，还是不理解“_WDWORD(0x402F00A0,0x00000030); // IPTXDAT”这个语句中，为何要把0x402F00A0这一寄存器的数据配置成x00000030。事实上，RM中，这部分描述很少。网上有种说法，说这是为了配置成“0011 = CAS Latency = 3个时钟周期”，对吗？
谢谢！
