Memory timing
806
NS9750 Hardware Reference
Static RAM asynchronous page mode read, WTPG = 1

Figure 114: Static RAM asynchronous page mode read, WTPG = 1 timing

WTPG = 1

WTRD = 2

If the PB field is set to 1, all four byte_lane signals will go low for 32-bit,

16-bit, and 8-bit read cycles.

The asy nchron ous pag e mode w ill rea d 16 byt es in a p age cyc le. A 32 -bit bu s

will do four 32-bit reads, as shown (3-2-2-2). A 16-bit bus will do eight 16-

bit reads (3-2-2-2-3-2-2-2) per page cycle, and an 8-bit bus will do sixteen

8-bit reads (3-2-2-2-3-2-2-2-3-2-2-2-3-2-2-2) per page cycle. 3-2-2-2 is the

example used here, but the WTRD and WTPG fields can set them

differently.

Notes:
1The length of the first cycle in the page is determined by the WTRD field.
2The length of the 2nd, 3rd, and 4th cycles is determined by the WTPG field.
3This is the starting address. The least significant two bits will always be ‘00.’
4The least significant two bits in the second cycle will always be ‘01.’
5The least significant two bits in the third cycle will always be ‘10.’
6The least significant two bits in the fourth cycle will always be ‘11.’
7If the PB field is set to 0, the byte_lane signal will always be high during a read cycle.
Note-1 Note-2 Note-2 Note-2
M24M23
M28M27
M20M19
M18M18M17
M26
M25
M26
M25
Note-3 Note-4 Note-5 Note-6
Note-7
CPU clock / 2
data<31:0>
addr<27:0>
st_cs_n<3:0>
oe_n
byte_lane<3:0>