ACT-F512K8N-090F7I Просмотр технического описания (PDF) - Aeroflex Corporation
Номер в каталоге
Компоненты Описание
производитель
ACT-F512K8N-090F7I Datasheet PDF : 21 Pages
| |||
If Data Polling or the Toggle Bit indicates the device has
been written with a valid erase command, D3 may be
used to determine if the sector erase timer window is still
open. If D3 is high ("1") the internally controlled erase
cycle has begun; attempts to write subsequent com-
mands to the device will be ignored until the erase oper-
ation is completed as indicated by Data Polling or Toggle
Bit. If D3 is low ("0"), the device will accept additional
sector erase commands. To ensure the command has
been accepted, the software should check the status of
D3 prior to and following each subsequent sector erase
command. If D3 were high on the second status check,
the command may not have been accepted. See Table 4
Sector Protection
Algorithims
SECTOR PROTECTION
The ACT-F512K8 features hardware sector protection
which will disable both program and erase operations to
an individual sector or any group of sectors. To activate
this mode, the programming equipment must force VID
on control pin OE and address pin A9. The sector
addresses should be set using higher address lines A18,
A17, and A16. The protection mechanism begins on the
falling edge of the WE pulse and is terminated with the
rising edge of the same.
To verify programming of the protection circuitry, the pro-
gramming equipment must force VID on address pin A9
with CE and OE at VIL and WE at VIH. Scanning the sec-
tor addresses (A16, A17, and A18) while (A6, A1, A0) =
(0, 1, 0,) will produce a logical "1" code at device output
D0 for a protected sector. Otherwise the device will read
00H for unprotected sector. In this mode, the lower order
addresses, except for 0, A1, and A6 are don't care.
It is also possible to verify if a sector is protected during
the sector protection operation. This is done by setting
A6 = CE = OE = VIL and WE = VIH (A9 remains high at
VID). Reading the device at address location XXX2H,
where the higher order addresses (A18, A17, and A16)
define a particular sector, will produce 01H at data out-
puts (D0 - D7) for a protected sector.
SECTOR UNPROTECT
The ACT-F512K8 also features a sector unprotect mode,
so that a protected sector may be unprotected to incor-
porate any changes in the code. All sectors should be
protected prior to unprotecting any sector.
To activate this mode, the programming equipment must
force Vid on control pins OE, CE, and address pin A9.
The address pins A6, A16, and A12 should be set to VIH.
The unprotection mechanism begins on the falling edge
of the WE pulse and is terminated with the rising edge of
the same.
It is also possible to determine if a sector is unprotected
in the system by writing the autoselect command and A6
is set at VIH. Performing a read operation at address
location XXX2H, where the higher order addresses (A18,
A17, and A16) define a particular sector address, will pro-
duce 00H at data outputs (D0-D7) for an unprotected
sector.
Aeroflex Circuit Technology
8
SCD1668 REV A 4/28/98 Plainview NY (516) 694-6700
Share Link: 