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FM93C56A Rev. A
F
128 by 16-Bit Organization
(FM93C56A when ORG = V
CC
or NC)
Instruction
SB
OP-Code
2 Bits
Address
8 Bits
Data
16 Bits
Comments
READ
1
10
A7–A0
Read data stored in selected registers.
EWEN
1
00
11XXXXXX
Enables programming modes.
EWDS
1
00
00XXXXXX
Disables all programming modes.
ERASE
1
11
A7–A0
Erase selected register.
WRITE
1
01
A7–A0
D15–D0
Writes data pattern D15–D0 into selected register.
ERAL
1
00
10XXXXXX
Erases all registers.
WRAL
1
00
01XXXXXX
D15–D0
Writes data pattern D15–D0 into all registers.
Note:
The A7 bit is a "don't care" bit, but must be entered in the Address string.
Note:
X = Don't care.
256 by 8-Bit Organization
(FM93C56A when ORG = GND)
Instruction
SB
OP-Code
2 Bits
Address
9 Bits
Data
8 Bits
Comments
READ
1
10
A8–A0
Read data stored in selected registers.
EWEN
1
00
11XXXXXXX
Enables programming modes.
EWDS
1
00
00XXXXXXX
Disables all programming modes.
ERASE
1
11
A8–A0
Erase selected register.
WRITE
1
01
A8–A0
D7–D0
Writes data pattern D7–D0 into selected registers.
ERAL
1
00
10XXXXXXX
Erases all registers.
WRAL
1
00
01XXXXXXX
D7–D0
Writes data pattern D7–D0 into all registers.
Note:
The A8 bit is a "don't care" bit, but must be entered in the Address string.
Note:
X = Don't care.
Functional Description
Programming:
1. Programming is initiated by clocking in the Start Bit, Opcode
bits, Address bits and the 8/16 data bits (refer to the ORG
pin section).
2. Programming is started by bringing the CS pin low. Once the
programming cycle is started, it cannot be stopped. (Bringing
V
CC
low will stop any programming, but will also result in
data corruption.)
3. The status of the programming cycle (BUSY or READY) is
observed by bringing the CS pin high and observing the
output state. If the output is LOW, the device is still program-
ming (BUSY). If the output is HIGH, the programming cycle
has been completed and the device is ready for the next
operation. Note that the output will be tri-stated each time
CS is brought low and the READY/BUSY status will be
shown each time CS is brought high.
4. After programming, the READY state (output HIGH) can be
reset and the output tri-stated by clocking in a single Start
Bit. This Start Bit can be the first bit in a command string, or
CS can be brought low again to reset all internal circuits. In
any case, clocking in a '1' bit will tri-state the output.
Read (READ)
The READ instruction outputs serial data on the DO pin. After a
READ instruction is received, the instruction and address are
decoded, followed by data transfer from the selected memory
register into a serial-out shift register. A dummy bit (logical 0)
precedes the serial data output string. Output data changes are
initiated by a low to high transition of SK after the last address bit
(A0) is clocked in.
Erase/Write Enable (EWEN)
When V
CC
is applied to the part, it “powers up” in the Erase/Write
Disable (EWDS) state. Therefore, all programming modes must
be preceded by an Erase/Write Enable (EWEN) instruction. Once
an Erase/Write Enable instruction is executed, programming
remains enabled until an Erase/Write Disable (EWDS) instruction
is executed or V
CC
is removed from the part.