M45PE10 Operating features
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4.3 A fast way to modify data
The Pa ge Prog ram (PP) in st ruct ion provides a f ast way of modif y ing data (u p t o 256
conti guous byt es at a time), pro v ided th at it only involves resetting bits to 0 that had
previ o us ly been set to ‘1 ’.
This might be:
when the designer is programmi ng the device for the first time
when the designer knows that the page has al ready been erased by an earlier page
eras e ( P E) or s ec tor erase ( S E) instructio n. This is useful, for examp le , whe n s t or i ng a
fast stream of data, having first pe rformed the e r ase cycle wh en time was availa ble
when the desi gner knows tha t th e only changes in volve rese tting bits t o 0 t hat are s ti ll
set to ‘1’. Whe n t his method is possibl e, it has the addit ional ad vantage of mini m izing
the num ber of un necessary erase operat ions, and t he extra stress incurred by e ach
page.
For optimized timings, it is recommended to use the page program (PP) instruction to
program all consecutive targeted bytes in a single sequence versus using several page
program (PP) sequences with each containing only a few bytes (see Section 6.8: Page
program (PP), Tabl e 14: AC characteristics (50 MHz operation), an d Table 15: AC
characteristics (75 MHz operatio n, T9HX (0.11 µm ) proc ess) ).
4.4 Polling during a write, program or erase cycle
A furt her imp roveme nt in the writ e, pr ogram o r era se time can be achie ved by not wa itin g for
the worst case delay (t
PW
, t
PP
, t
PE
, or t
SE
). The wri te in progr e s s (WIP) bit is provided in the
status registe r so that the a pplicat ion program ca n m onit or its value, polling it to esta blish
when the previous cycle is complete.
4.5 Reset
An internal power on reset circuit helps protect against inadvertent data writes. Addition
protection is provided by driving Reset (R eset) Low du ring the power-on process, and only
driving it High when V
CC
has reached the correct vol tag e level, V
CC
(min).
4.6 Active power, standby power and deep power-down modes
When Chip Select (S ) is Low, the device is selected, and in the active power mode.
When Chip Select (S) is Hi gh, the d evic e is dese lected , but coul d rema in in th e active po wer
mode until all internal cycles have completed (program, erase, write). The device then goes
in to the standby power mode. The device consumption drops to I
CC1
.
The deep power-down mode is entered when the specific instruction (the deep power-down
(DP) instruction) is executed. The device consumption drops further to I
CC2
. The device
remains in this mode until another specific instruction (the release from deep power-down
and read electronic signature (RES) instruction) is executed.
All other instructions are ignored while the device is in the deep power-down mode. This can
be use d as an ext ra sof twa re prot ecti on mecha nis m, w hen th e dev ic e is not i n ac tive u se, to
protec t the dev ice from inadv er te nt wr ite, pro gram or erase ins t ruc t i on s .