8-Bit CMOS Microcontorller

GMS97C2051/L2051

HYUNDAI MicroElectonics

Features

Compatible with MCS-51

Products

2 Kbytes of programmable EPROM

4.25V to 5.5V Operating Range (GMS97C2051)

2.70V to 3.6V Operating Range (GMS97L2051)

Version for 12MHz / 24 MHz Operating frequency (GMS97C2051)

Only 12MHz Operating frequency (GMS97L2051)

Two-Level Program Memory Lock with encryption array

128 bytes SRAM

15 Programmable I/O Lines

Two 16-Bit Timer/Counters

Programmable serial USART

Five Interrupt Sources

Direct LED Drive Outputs

On-Chip Analog Comparator

Low Power Idle and Power Down Modes

Description

The GMS97C2051/L2051 is a high-performance CMOS 8-bit microcontroller with 2Kbytes of programmable

EPROM. The device is compatible with the industry standard MCS-51

instruction set and pinout. The HYUN-

DAI MicroElectronics GMS97C2051/L2051 is a powerful microcontroller which provides a highly flexible and

cost effective solution to many embedded control applications. The GMS97C2051/L2051 provides the following

standard features: 2Kbytes of EPROM, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five vector

two-level interrupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and

clock circuitry. In addition, the GMS97C2051/L2051 supports two software selectable power saving modes. The

Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue

functioning. The Power Down Mode saves the RAM contents but freezes the oscillator disabling all other chip

functions until the next hardware reset.

Pin Configuration

PDIP/SOP

(T0) P3.4

VCC
P1.7
P1.6
P1.5
P1.4
P1.3
P1.2
P1.1 (AIN1)
P1.0 (AIN0)
P3.7

RST

(RXD) P3.0
(TXD) P3.1

XTAL2
XTAL1

(

INT1

) P3.3

(T1) P3.5

GND

20
19
18
17
16
15
14
13
12
11

1
2
3
4
5
6
7
8
9
10

(

INT0

)P3.2

8-Bit CMOS Microcontorller

GMS97C2051/L2051

HYUNDAI MicroElectonics

Pin Description

Vcc

Supply voltage.

GND

Ground.

Port 1

Port 1 is an 8-bit bidirectional I/O port. Port pins P1.2
to P1.7 provide internal pullups. P1.0 and P1.1 re-
quire external pullups. P1.0 and P1.1 also serve as the
positive input (AIN0) and the negative input (AIN1),
respectively, of the on-chip precision analog compara-
tor. The Port 1 output buffers can sink 10mA and can
drive LED displays directly. When 1s are written to
Port1 pins, they can be used as inputs. When pins
P1.2 to P1.7 are used as inputs and are externally pulled
low, they will source current (I

) because of the inter-

nal pullups.
Port 1 also receives code data during EPROM pro-
gramming and program verification.

Port3

Port 3 pins P3.0 to P3.5, P3.7 are seven bidirectional
I/O pins with internal pullups. P3.6 is hard-wired as
an input to the output of the on-chip comparator and is
not accessible as a general purpose I/O pin. The Port
3 output buffers can sink 10mA. When 1s are written
to Port 3 pins they are pulled high by the internal pul-
lups and can be used as inputs. As inputs, Port 3 pins
that are externally being pulled low will source current
(I

) because of the pullups.

Port 3 also serves the functions of various special fea-
ture of the GMS97C2051 as listed below:

Port Pin

Alternate Functions

P3.0
P3.1
P3.2
P3.3
P3.4
P3.5

RXD ( serial input port )
TXD ( serial output port )

INT0 ( external interrupt 0 )

INT1( external interrupt 1 )
T0 ( timer 0 external input )
T1 ( timer 0 external input )

Port 3 also receives some control signals for EPROM
programming and programming verification.

RST

Reset input. All I/O pins are reset to 1s as soon as
RST goes high. Holding the RST pin high for two
machine cycles while the oscillator is running resets the
device.
This pin is also receives the 12.75V programming
supply voltage ( Vpp ) during EPROM programming.

XTAL1

Input to the inverting oscillator amplifier and input to
the internal clock operating circuit.

XTAL2

Output from the inverting oscillator amplifier.

Recommended Oscillator Circuit

XTAL1 and XTAL2 are the input and output, respec-
tively, of an inverting amplifier which can be config-
ured for use as an on-chip oscillator, as shown in Fig-
ure 1. To drive the device from an external clock
source, XTAL2 should be left unconnected while
XTAL1 is driven as shown in Figure 2.

Figure 1. Oscillator Connections

C 2

C 1

X T A L 2

X T A L 1

G N D

Notes: C1, C2 = 30pF

10pF for Crystals

( include stray capacitance )

Figure 2. External Clock Drive Configuration

XTAL2

XTAL1

GND

EXTERNAL

OSCILLATOR

SIGNAL

GMS97C2051/L2051

8-Bit CMOS Microcontroller

HYUNDAI MicroElectronics

Special Function Registers

A map of the on-chip memory area called the Special
Function Register (SFR) space is shown in the Table1,
Table 2 and Table 3.
Note that not all of the addresses are occupied, and
unoccupied addresses may not be implemented on the
chip. Read accesses to these addresses will in general
return random data, and write accesses will have an
indeterminate effect.

User software should not write 1s to these unlisted
locations, since they may be used in future products to
invoke new features. In that case, the reset or inactive
values of the new bits will always be 0.

Table 1. GMS97C2051/L2051 SFR Map and Reset Values

0F8H

0FFH

0F0H

00000000

0F7H

0E8H

0EFH

0E0H

ACC

00000000

0E7H

0D8H

0DFH

0D0H

PSW

00000000

0D7H

0C8H

0CFH

0C0H

0C7H

0B8H

XXX00000

0BFH

0B0H

11111111

0B7H

0A8H

0XX00000

0AFH

0A0H

0A7H

98H

SCON

00000000

SBUF

XXXXXXXX

9FH

90H

11111111

97H

88H

TCON

00000000

TMOD

00000000

TL0

00000000

TL1

00000000

TH0

00000000

TH1

00000000

8FH

80H

00000111

DPL

00000000

DPH

00000000

PCON

0XXX0000

87H

8-Bit CMOS Microcontorller

GMS97C2051/L2051

HYUNDAI MicroElectonics

Table 2. Bit Assignment of SFRs

Address Register

Bit7

Bit6

Bit5

Bit4

Bit3

Bit2

Bit1

Bit0

DPL

DPH

PCON

SMOD

GF1

GF0

IDLE

TCON

TF1

TR1

TF0

TR0

IE1

IT1

IE0

IT0

TMOD

GATE

C /

GATE

C /

TL0

TL1

TH0

TH1

SCON

SM0

SM1

SM2

REN

TB8

RB8

SBUF

ET1

EX1

ET0

EX0

PT1

PX1

PT0

PX0

PSW

RS1

RS0

ACC

- : This Bit Location is reserved

Bit manipulation is available

Bit manipulation is not available

Электронный компонент: GMS97C1051-24D