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网上看来的
DREQ
is used to signal if VS1003’s FIFO is capable of receiving data. If DREQ
is high, VS1003 can take at least 32 bytes of SDI data or one SCI command. When these
criteria are not met, DREQ is turned low, and the sender should stop transferring new data.
Because of the 32-byte safety area, the sender may send upto 32 bytes of SDI data at a
time without checking the status of DREQ, making controlling VS1003 easier for low-speed
microcontrollers.
Note: DREQ may turn low or high at any time, even during a byte transmission. Thus, DREQ
should only be used to decide whether to send more bytes. It should not abort a transmission
that has already started.
也是就是说, 如果 DREQ 为高, 尽管写32字节, 不客气,
但是实际上发现不是这样, 如果这么做, 声音可能出不来.
没办法, 写32字节或者更多的时候就需要检查 DREQ 的状态,
这样以来, 就比较费时间, 导致读 SD 卡时间紧迫,
反倒有时候没有数据给他吃, 效果也不好.
请教各位如何操作最好?
谢过了先! |
阿莫论坛20周年了!感谢大家的支持与爱护!!
曾经有一段真挚的爱情摆在我的面前,我没有珍惜,现在想起来,还好我没有珍惜……
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