DS2251T-32-16# Maxim Integrated Products, DS2251T-32-16# Datasheet - Page 6
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DS2251T-32-16#
Manufacturer Part Number
DS2251T-32-16#
Description
IC MCU 32KB 16MHZ 72-SIMM
Manufacturer
Maxim Integrated Products
Series
DS225xr
Datasheet
1.DS2251T-32-16.pdf
(22 pages)
Specifications of DS2251T-32-16#
Core Processor
8051
Core Size
8-Bit
Speed
16MHz
Connectivity
SIO, UART/USART
Peripherals
Power-Fail Reset, WDT
Number Of I /o
32
Program Memory Type
SRAM
Ram Size
32K x 8
Voltage - Supply (vcc/vdd)
4.5 V ~ 5.5 V
Oscillator Type
External
Operating Temperature
0°C ~ 70°C
Package / Case
72-SIMM
Processor Series
DS2251T
Core
8051
Data Bus Width
8 bit
Program Memory Size
32 KB
Data Ram Size
32 KB
Interface Type
UART
Maximum Clock Frequency
16 MHz
Number Of Programmable I/os
32
Number Of Timers
2
Operating Supply Voltage
4.75 V to 5.25 V
Maximum Operating Temperature
+ 70 C
Mounting Style
SMD/SMT
Minimum Operating Temperature
0 C
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
Eeprom Size
-
Program Memory Size
-
Data Converters
-
Lead Free Status / Rohs Status
Details
INSTRUCTION SET
The DS2251T executes an instruction set that is object code compatible with the industry standard 8051
microcontroller. As a result, software development packages such as assemblers and compilers that have
been written for the 8051 are compatible with the DS2251T.
A complete description of the instruction set and operation are provided in the Secure Microcontroller
User’s Guide.
MEMORY ORGANIZATION
Figure 2 illustrates the memory map accessed by the DS2251T. The entire 64k of program and 64k of
data are available to the byte-wide bus. This preserves the I/O ports for application use. The user controls
the portion of memory that is actually mapped to the byte-wide bus by selecting the Program Range and
Data Range. Any area not mapped into the NV RAM is reached via the Expanded bus on Ports 0 and 2.
An alternate configuration allows dynamic Partitioning of a 64k space as shown in Figure 3. Selecting
PES = 1 provides access to the real-time clock on the DS2251T and enables
access as shown in Figure 4. These selections are made using Special Function Registers. The memory
map and its controls are covered in detail in the Secure Microcontroller User’s Guide.
PIN
71
65
55
68
69
70
has fallen below the V
DS2251T will drive this pin to a logic 0. Because the micro is lithium backed, this signal is
guaranteed even when V
low externally. This allows multiple parts to synchronize their power-down resets.
It corresponds to V
even when V
input.
connected to a micro interrupt input.
input.
SQW. Square-wave output from the DS1283 real-time clock. Can be programmed to output
a 1024Hz square wave.
INTB
INTP
INTA
VRST
PF
. This output goes to a logic 0 to indicate that the micro has switched to lithium backup.
.
.
.
. This I/O pin (open-drain with internal pullup) indicates that the power supply (V
INTP
INTA
INTB
from the real-time clock. This open-drain output requires a pullup and may be
from the real-time clock. This output may be connected to a micro interrupt
CC
from the real-time clock. This output may be connected to a micro interrupt
= 0V.
CC
< V
CCMIN
CC
LI
. Because the micro is lithium backed, this signal is guaranteed
= 0V. Because it is an I/O pin, it will also force a reset if pulled
level and the micro is in a reset state. When this occurs, the
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DESCRIPTION
PE3
and
PE4
for peripheral
CC
)