starterware boot 读取 nand page 与 sy***ios 中 读取nand page 时间差异很大
你好：
遇到的问题为：
starterware boot 读取 nand page 大小528字节 耗时为4-5ms；
sy***ios
中 读取nand page 大小528字节，耗时为1.5ms；
代码实现是一样的；时间差异很大的原因不知道是为什么？
DSTATUS NAND_initialize (void)
{
DWORD i, j, w, /*d[2],*/ bb, bf, flag = SIZE_PAGE/4;
BYTE ww;
WORD stat;
static DWORD *d;
nand_init();
flush_block();
d = BlockBuff[0];
/* Create physical block status table */
for (bb = 0, i = N_RES_BLKS; i < N_TOTAL_BLKS; i++) {
read_page(d, i * N_SIZE_BLK, 1, N_GET_BLOCK_BUFF); /* Read two DWORDs of the spare area of 1st page */
bf = 0;
ww = ~(d[flag] & 0xff); /* Check bad block mark */
if (ww & (ww - 1)) { /* Bad block (2 or more zeros) */
bb++; bf = 1;
} else {
w = d[flag+1]; /* Get block status */
if (w != 0xFFFFFFFF && (WORD)w != (WORD)(~w >> 16)) { /* Bit error in the status? */
read_page(d, i * N_SIZE_BLK + 1, 1, N_GET_BLOCK_BUFF); /* Read 2nd page */
w = d[flag+1]; /* Get block status */
if (w != 0xFFFFFFFF && (WORD)w != (WORD)(~w >> 16)) {
bb++; bf = 1;
}
}
}
stat = bf ? 0xFFFE : (WORD)w;
BlockStat
[/tr]
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