EN27C512 Datasheet, PDF (4/12 Pages) List of Unclassifed Manufacturers – 512KBIT EPROM (64K x 8)

EN27C512
PROGRAM INHIBIT MODE
Programming of multiple EN27C512 in parallel with different data is also easily accomplished
by using the Program Inhibit Mode. Except for CE , all like inputs of the parallel EN27C512
may be common. A TTL low-level program pulse applied to an EN27C512 CE input with
OE /V_PP = 12.75 ± 0.25V will program that EN27C512. A high-level CE input inhibits the
other EN27C512 from being programmed.
PROGRAM VERIFY MODE
Verification should be performed on the programmed bits to determining that they were
correctly programmed. The verification should be performed with OE /VPP and CE at VIL. Data
should be verified at t_DV after the falling edge of CE .
AUTO PRODUCT IDENTIFICATION
The Auto Product Identification mode allows the reading out of a binary code from an EPROM that
will identify its manufacturer and type. This mode is intended for use by programming equipment
for the purpose of automatically matching the device to be programmed with its corresponding
programming algorithm. This mode is functional in the 25°C ± 5°C ambient temperature range
that is required when programming the EN27C512.
To activate this mode, the programming equipment must force 12.0 V ± 0.5V on address line A9
of the EN27C512. Two identifier bytes may then be sequenced from the device outputs by
toggling address line A0 from V_IL to V_IH, when A1 = V_IH. All other address lines must be held at
V_IL during Auto Product Identification mode.
Byte 0 (A0 = V_IL) represents the manufacturer code, and byte 1 (A0 = V_IH), the device code. For
the EN27C512, these two identifiers bytes are given in the Mode Select Table. All identifiers for
manufacturer and device codes will possess odd parity, with the MSB (DQ7) defined as the parity
bit. When A1 = V_IL, the EN27C512 will read out the binary code of 7F, continuation code, to
signify the unavailability of manufacturer ID codes.
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