ONT color=#ff00ff>0x88// MAX7456 FM_ADDRH register#define FM_ADDRH_WRITE 0x09#define FM_ADDRH_READ 0x89// MAX7456 FM_ADDRL register#define FM_ADDRL_WRITE 0x0A#define FM_ADDRL_READ 0x8A// MAX7456 FM_DATA_IN register#define FM_DATA_IN_WRITE 0x0B#define FM_DATA_IN_READ 0x8B// MAX7456 FM_DATA_OUT register#define FM_DATA_OUT_READ 0xC0// MAX7456 STATUS register#define STATUS_READ 0xA0#define STATUS_40_RESET_BUSY 0x40#define STATUS_20_NVRAM_BUSY 0x20#define STATUS_04_LOSS_OF_SYNC 0x04#define STATUS_02_PAL_DETECTED 0x02#define STATUS_01_NTSC_DETECTED 0x01// MAX7456 requires clearing OSD Black Level// register bit 0x10 after reset#define OSDBL_WR 0x6C#define OSDBL_RD 0xEC#define OSDBL_10_DisableAutoBlackLevel 0x10結(jié)論和性能
MAX7456評估板采用工作在20MHz時鐘的MAXQ2000微控制器,該微控制器包含內(nèi)部硬件SPI控制器。因此,MAX7456的SPI端口可以全速工作。上述軟件SPI程序工作速度低于硬件控制器。不過針對客戶缺少硬件SPI端口的工作環(huán)境,程序已優(yōu)化至最簡。
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