M50FLW080A datasheet(21/64 Pages) STMICROELECTRONICS

21 / 64 page

M50FLW080A, M50FLW080B

Bus operations

21/64

Figure 7.

FWH Bus Write waveforms

Table 7.

FWH Bus Write field definitions

Clock

Cycle

Number

Clock

Cycle

Count

Field

FWH0-

FWH3

Memory

I/O

Description

START

1110b

On the rising edge of CLK with FWH4 Low, the contents of

FWH0-FWH3 indicate the start of a FWH Write Cycle.

IDSEL

XXXX

Indicates which FWH Flash Memory is selected. The value on

FWH0-FWH3 is compared to the IDSEL strapping on the

FWH Flash Memory pins to select which FWH Flash Memory

is being addressed.

3-9

ADDR

XXXX

A 28-bit address is transferred, with the most significant

nibble first. Address lines A20-21 and A23-27 are treated as

Don’t Care during a normal memory array access, with

A22=1, but are taken into account for a register access, with

A22=0. (See Table 15)

MSIZE

XXXX

0000(Single Byte Transfer) 0001 (Double Byte Transfer)

0010b (Quadruple Byte Transfer).

11-18

M=2/4/8

DATA

XXXX

Data transfer is two cycles, starting with the least significant

nibble. (The first pair of nibbles is that at the address with A1-

A0 set to 00, the second pair with A1-A0 set to 01, the third

pair with A1-A0 set to 10, and the fourth pair with A1-A0 set

to 11. In Double Byte Program the first pair of nibbles is that

at the address with A0 set to 0, the second pair with A0 set to

previous +1

TAR

1111b

The host drives FWH0-FWH3 to 1111b to indicate a

turnaround cycle.

previous +1

TAR

1111b

(float)

The FWH Flash Memory takes control of FWH0-FWH3 during

this cycle.

previous +1

SYNC

0000b

The FWH Flash Memory drives FWH0-FWH3 to 0000b,

indicating it has received data or a command.

previous +1

TAR

1111b

The FWH Flash Memory drives FWH0-FWH3 to 1111b,

indicating a turnaround cycle.

previous +1

TAR

1111b

(float)

N/A

The FWH Flash Memory floats its outputs and the host takes

control of FWH0-FWH3.

AI08434B

CLK

FWH4

FWH0-FWH3

Number of

clock cycles

START

IDSEL

ADDR

MSIZE

DATA

TAR

SYNC

TAR

1171

212

M50FLW080A Datasheet(PDF) 21 Page - STMicroelectronics

M50FLW080A Datasheet(HTML) 21 Page - STMicroelectronics

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64

Datasheet Download

Link URL