IS93C46A Datasheet, PDF (3/13 Pages) Integrated Silicon Solution, Inc – 1,024-BIT SERIAL ELECTRICALLY ERASABLE PROM

IS93C46A
ISSI ^®
Write Enable (WEN)
The write enable (WEN) instruction must be executed
before any device programming (WRITE, WRALL,
ERASE, and ERAL) can be done. When Vcc is applied,
this device powers up in the write disabled state. The
device then remains in a write disabled state until a WEN
instruction is executed. Thereafter, the device remains
enabled until a WDS instruction is executed or until Vcc
is removed. (See Figure 4.) (Note: Chip select must
remain LOW until Vcc reaches its operational value.)
Write (WRITE)
The WRITE instruction includes 8 or 16 bits of data to be
written into the specified register. After the last data bit
has been applied to DIN, and before the next rising edge
of SK, CS must be brought LOW. If the device is write-
enabled, then the falling edge of CS initiates the self-
timed programming cycle (see WEN).
If CS is brought HIGH, after a minimum wait of 250 ns (5V
operation) after the falling edge of CS (tCS) DOUT will
indicate the READY/BUSY status of the chip. Logical “0”
means programming is still in progress; logical “1” means
the selected register has been written, and the part is
ready for another instruction (see Figure 5). The READY/
BUSY status will not be available if: a) The CS input goes
HIGH after the end of the self-timed programming cycle,
tWP; or b) Simultaneously CS is HIGH, Din is HIGH, and
SK goes HIGH, which clears the status flag.
Write All (WRALL)
The write all (WRALL) instruction programs all registers
with the data pattern specified in the instruction. As with the
WRITE instruction, the falling edge of CS must occur to
initiate the self-timed programming cycle. If CS is then
brought HIGH after a minimum wait of 250 ns (tCS), the
DOUT pin indicates the READY/BUSY status of the chip (see
Figure 6).
Write Disable (WDS)
The write disable (WDS) instruction disables all programming
capabilities. This protects the entire device against acci-
dental modification of data until a WEN instruction is
executed. (When Vcc is applied, this part powers up in the
write disabled state.) To protect data, a WDS instruction
should be executed upon completion of each programming
operation.
Erase Register (ERASE)
After the erase instruction is entered, CS must be brought
LOW. The falling edge of CS initiates the self-timed internal
programming cycle. Bringing CS HIGH after a minimum of
tCS, will cause DOUT to indicate the READ/BUSY status of the
chip: a logical “0” indicates programming is still in progress;
a logical “1” indicates the erase cycle is complete and the
part is ready for another instruction (see Figure 8).
Erase All (ERAL)
Full chip erase is provided for ease of programming. Erasing
the entire chip involves setting all bits in the entire memory
array to a logical “1” (see Figure 9).
INSTRUCTION SET - IS93C46A
Instruction
Start Bit
READ
1
WEN (Write Enable)
1
WRITE
1
WRALL (Write All Registers) 1
WDS (Write Disable)
1
ERASE
1
ERAL (Erase All Registers) 1
OP Code
10
00
01
00
00
11
00
8-bit Organization
(ORG = GND)
Address ⁽¹⁾ Input Data
(A6-A0)
—
11xxxxx
—
(A6-A0)
(D7-D0) ⁽³⁾
01xxxxx (D7-D0) ⁽³⁾
00xxxxx
—
(A6-A0)
—
10xxxxx
—
Notes:
1. x = Don't care bit.
2. If input data is not 16 bits exactly, the last 16 bits will be taken as input data.
3. If input data is not 8 bits exactly, the last 8 bits will be taken as input data.
16-bit Organization
(ORG = Vcc)
Address ⁽¹⁾ Input Data
(A5-A0)
—
11xxxx
—
(A5-A0) (D15-D0) ⁽²⁾
01xxxx (D15-D0) ⁽²⁾
00xxxx
—
(A5-A0)
—
10xxxx
—
Integrated Silicon Solution, Inc. — www.issi.com — 1-800-379-4774
3
Rev. E
06/07/04