SST89E554 SST [Silicon Storage Technology, Inc], SST89E554 Datasheet - Page 9

• Manufacturer Part Number: SST89E554
• Description: FlashFlex51 MCU
• Manufacturer: SST [Silicon Storage Technology, Inc]

FlashFlex51 MCU
SST89E564 / SST89V564 / SST89E554 / SST89V554
Preliminary Specifications
TABLE
©2001 Silicon Storage Technology, Inc.
ALE/PROG#
Symbol
1. I = Input; O = Output
2. It is not necessary to receive a 12V programming supply voltage during flash programming.
XTAL1
XTAL2
RST
EA#
V
Vss
DD
2-1: P
IN
Type
D
I/O
O
I
I
I
I
I
ESCRIPTIONS
1
Name and Functions
Reset: While the oscillator is running, a high logic state on this pin for two machine cycles will
reset the device. After a reset, if the PSEN# pin is driven by a high-to-low input transition
while the RST input pin is held high, the device will enter the External Host mode, otherwise
the device will enter the Normal operation mode.
External Access Enable: EA# must be driven to V
code from the External Program Memory. EA# must be driven to V
cution. However, Security lock level 4 will disable EA#, and program execution is only possi-
ble from internal program memory. The EA# pin can tolerate a high voltage
(see “Absolute Maximum Stress Ratings” on page 47).
Address Latch Enable: ALE is the output signal for latching the low byte of the address dur-
ing accesses to external memory. This pin is also the programming pulse input (PROG#) for
the external host mode. ALE is activated twice each machine cycle, except when access to
External Data Memory, one ALE activation is skipped in the second machine cycle. However,
if AO is set to 1, ALE is disabled. (see “Auxiliary Register (AUXR)” on page 20)
Oscillator: Input and output to the inverting oscillator amplifier. XTAL1 is input to internal
clock generation circuits from an external clock source.
Power Supply: Supply voltage during normal, Idle, Power Down, and Standby Mode opera-
tions.
Ground: Circuit ground. (0V reference)
(C
ONTINUED
) (2
OF
2)
9
IL
in order to enable the device to fetch
IH
for internal program exe-
S71181-03-000 9/01
2
of 12V
T2-1.6 384
384