TI中文支持网想请教各位专家，我是用omap35芯片。用GPMC方式异步读取数据，在OEOTIME有效后，信号的建立保持时间有多长？就是想问OE有效之后最长可以经过几个GPMC_FCLK把数据放到数据线上？
Chris Meng：
你好，
OEOFFSTIME减去OEONTIME就是你需要的时间。
OEOFFSTIME和OEONTIME的长度可以在下面寄存器里面配置，理论上可以配置最大差值为31-0=31 GPMC_FCLK cycles。但是请注意，GPMC上的外部设备必须能够接受这样的时序才可以。
The GPMC.GPMC_CONFIG4_i[3:0] OEONTIME field (where i = 0 to 7) defines the nOE/nRE signalassertion time relative to start access time. It is applicable only to read accesses.The GPMC.GPMC_CONFIG4_i[12:8] OEOFFTIME field defines the nOE/nRE signal deassertion timerelative to start access time. It is applicable only to read accesses.
12:8 OEOFFTIME nOE de-assertion time from start cycle time RW 0x100x00: 0 GPMC_FCLK cycle0x01: 1 GPMC_FCLK cycle…0x1F: 31 GPMC_FCLK cycles3:0 OEONTIME nOE assertion time from start cycle time RW 0x30x0: 0 GPMC_FCLK cycle0x1: 1 GPMC_FCLK cycle…0xF: 15 GPMC_FCLK cycles
