M27W512 datasheet(9/22 Pages) STMICROELECTRONICS

9 / 22 page

M27W512

Device operation

9/22

Figure 3.

Programming flowchart

2.5

Programming

The M27W512 has been designed to be fully compatible with the M27C512 and has the

same electronic signature. As a result, the M27W512 can be programmed as the M27C512

on the same programming equipment applying 12.75V on VPP and 6.25V on VCC. The

M27W512 can use PRESTO IIB Programming Algorithm that drastically reduces the

programming time. Nevertheless to achieve compatibility with all programming equipment,

PRESTO II Programming Algorithm can be used as well. When delivered, all bits of the

M27W512 are in the '1' state. Data is introduced by selectively programming '0's into the

desired bit locations. Although only '0's will be programmed, both '1's and '0's can be

present in the data word. The M27W512 is in the programming mode when VPP input is at

12.75V and E is pulsed to VIL. The data to be programmed is applied to 8 bits in parallel to

the data output pins. The levels required for the address and data inputs are TTL. VCC is

specified to be 6.25V ± 0.25V.

AI00738C

n = 0

Last

Addr

VERIFY

E = 100

μs Pulse

++n

= 25

++ Addr

VCC = 6.25V, VPP = 12.75V

FAIL

CHECK ALL BYTES

1st: VCC = 5V

2nd: VCC = 2.7V

YES

SET MARGIN MODE

RESET MARGIN MODE

M27W512 Datasheet(PDF) 9 Page - STMicroelectronics