s3c2410 storage system

1 SDRAM addressing:

The board uses a modern sdram chip 4M×16b×4Bank, which is 32MB. It should have 25 address lines, but the chip only provides 13 address lines, 2 bank select lines (BA0, BA1), and two chip select signals. How to address it?
Answer from: http://www.52rd.com/Blog/Archive_Thread.asp?SID=11206

Let's take the HY57V561620 film as an example.

From the chip data sheet, we can learn that: 4M×16b×4Bank, that is, a total of 32MB, providing 13 address lines (row address lines RA0-RA12, column address lines CA0-CA8 shared by row and column address lines), 2 bank select lines (BA0, BA1).

Two bank selection lines (BA0, BA1) can select four banks, which means we can analyze only one bank.

One bank is 4Mx16bit, which requires 23 address lines. According to the above addressing method, the space of one bank = the space accessible by the row address x the space accessible by the column address.

The size of 1 Bank = 2^13 x 2^9 = 2^22.

There are only 22, how come there is still one missing? J (Hehe)

This is because the chip uses half-word as a storage unit. That is, two words at a time, so 2^22 x 2=2^23. You can access the entire bank.

2 nand flash

1) The address line and data line of nandflash are shared, and it is read and written in blocks, and is mapped to ngcs1 (the 0 address of ngcs0 only hangs 4k of internal ram), so you can't run programs directly on it. And when the board is set to start from nandflash, it actually copies the first 4k of the content on nandflash to the internal ram, and then runs the program from the internal ram. The advantage of nand is that it is relatively large and can be used as a storage device like a hard disk.

3 nor flash

The advantage of nor flash is random reading, and programs can be run directly on it. The disadvantage is that the cost is relatively high. The Ulong board only has 2M.