Am28F256A 13
Embedded Programming Algorithm
The Embedded Progr am Se tup i s a command only op-
eration that stages the device for automatic program-
ming. Embedded Program Setup is performed by
writing 10h or 50h to the command register.
Once the Embed ded Setup Prog r am ope r ation is per-
for med, the next WE# pulse causes a transition to an
activ e pro gr amming oper ation. Address es are lat ched
on the falling edge of CE# or WE# pulse, whichever
happens later. Data is latched on the rising edge of
WE# or CE# , whiche ver happ ens first. The rising e dge
of WE# also begins the programming operation. The
system is not required to provide further controls or
timings. The device wi ll automatically provide an ade-
quate internally generated program pulse and verify
margin. The automatic programming operation is
completed when the d ata on DQ7 is equi valent to dat a
written to th is bit (s ee Write Oper at io n Stat us s ecti on)
at which time the device returns to Read mode.
Figure 2 and Table 5 illustrate the Embedded Program
algorithm, a typical command string, and bus operation.
Table 5. Embedded Programming Algorithm
Note: See AC and DC Characteristics for values of V
PP
parameters. The V
PP
power supply can be hard-wired to the device or
switchable. When V
PP
is switched, V
PPL
may be ground, no connect with a resistor tied to ground, or less than V
CC
+ 2 .0 V. Re f er
to Functional Description. Device is either powered-down, erase inhibit or program inhibit.
Bus Operations Command Comments
Standby Wait for V
PP
Ramp to V
PPH
(see Note)
Write Embedded Program Setup Command Data = 10h or 50h
Write Embedded Program Command Valid Address/Data
Read Data
# Polling to Verify Completion
Read Available for Read Operations
START
Apply V
PPH
Write Embedded Setup Program Command
Write Embedded
Program Command (A/D)
Programming Completed
Yes
Data# Poll Device
Increme nt Add res s
No
18879C-7
Figure 2. Embedded Programming Algorithm
Last Address