at89ls51-16si ATMEL Corporation, at89ls51-16si Datasheet - Page 6

• Manufacturer Part Number: at89ls51-16si
• Description: At89ls51, Low-voltage Microcontroller With 4k Bytes In-system Programmable Flash
• Manufacturer: ATMEL Corporation

4.10
4.11
4.12
5. Special Function Registers
6
EA/VPP
XTAL1
XTAL2
AT89LS51
External Access Enable. EA must be strapped to GND in order to enable the device to fetch
code from external program memory locations starting at 0000H up to FFFFH. Note, however,
that if lock bit 1 is programmed, EA will be internally latched on reset.
EA should be strapped to V
This pin also receives the 12-volt programming enable voltage (V
Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
Output from the inverting oscillator amplifier
A map of the on-chip memory area called the Special Function Register (SFR) space is shown in
Table
Note that not all of the addresses are occupied, and unoccupied addresses may not be imple-
mented on the chip. Read accesses to these addresses will in general return random data, and
write accesses will have an indeterminate effect.
5-1.
CC
for internal program executions.
PP
) during Flash programming.
3053B–MICRO–3/05