83C749 Philips Semiconductors, 83C749 Datasheet - Page 5

• Manufacturer Part Number: 83C749
• Description: 80C51 8-bit microcontroller family 2K/64 OTP/ROM/ 5 channel 8-bit A/D/ PWM/ low pin count
• Manufacturer: Philips Semiconductors

1. AV
2. When P0.2 is at or close to 0 volt, it may affect the internal ROM operation. We recommend that P0.2 be tied to V
Philips Semiconductors
PIN DESCRIPTION
NOTE:
1998 Apr 23
V
V
P0.0–P0.4
P1.0–P1.7
P3.0–P3.7
RST
X1
X2
AV
AV
MNEMONIC
SS
CC
80C51 8-bit microcontroller family
2K/64 OTP/ROM, 5 channel 8-bit A/D, PWM, low pin count
in the range 4.5V to 5.5V.
(e.g., 2k ).
CC
SS
SS
1
1
(reference ground) must be connected to 0V (ground). AV
PIN NO.
13–17,
23, 24
20–22
13–17
27–25
5–1,
8–6
12
28
20
21
22
10
19
18
11
6
7
8
9
TYPE
I/O
I/O
I/O
O
I
I
I
I
I
I
I
I
I
I
I
I
I
Circuit Ground Potential.
Supply voltage during normal, idle, and power-down operation.
Port 0: Port 0 is a 5-bit bidirectional port. Port 0.0–P0.2 are open drain. Port 0.0–P0.2 pins that have
1s written to them float, and in that state can be used as high-impedance inputs. P0.3–P0.4 are
bidirectional I/O port pins with internal pull-ups. These pins are driven low if the port register bit is
written with a 0. The state of the pin can always be read from the port register by the program. Port 0.3
and 0.4 have internal pull-ups that function identically to port 3. Pins that have 1s written to them are
pulled high by the internal pull-ups and can be used as inputs.
While P0.0 anbd P0.1 differ from “standard TTL” characteristics, they are close enough for the pins to
still be used as general-purpose I/O.
V
OE/PGM (P0.1) – Input which specifies verify mode (output enable) or the program mode.
OE/PGM = 1 output enabled (verify mode).
OE/PGM = 0 program mode.
ASEL (P0.0) – Input which indicates which bits of the EPROM address are applied to port 3.
ASEL = 0 low address byte available on port 3.
ASEL = 1 high address byte available on port 3 (only the three least significant bits are used).
Port 1: Port 1 is an 8-bit bidirectional I/O port with internal pull-ups. Port 1 pins that have 1s written to
them are pulled high by the internal pull-ups and can be used as inputs. P0.3–P0.4 pins are
bidirectional I/O port pins with internal pull-ups. As inputs, port 1 pins that are externally pulled low will
source current because of the internal pull-ups. (See DC Electrical Characteristics: I
serves the special function features of the SC80C51 family as listed below:
INT0 (P1.5): External interrupt.
INT1 (P1.6): External interrupt.
T0 (P1.7): Timer 0 external input.
ADC0 (P1.0)–ADC4 (P1.4): Port 1 also functions as the inputs to the five channel multiplexed A/D
converter. These pins can be used as outputs only if the A/D function has been disabled. These pins
can be used as digital inputs while the A/D converter is enabled.
Port 1 serves to output the addressed EPROM contents in the verify mode and accepts as inputs the
value to program into the selected address during the program mode.
Port 3: Port 3 is an 8-bit bidirectional I/O port with internal pull-ups. Port 3 pins that have 1s written to
them are pulled high by the internal pull-ups and can be used as inputs. As inputs, port 3 pins that are
externally being pulled low will source current because of the pull-ups. (See DC Electrical
Characteristics: I
programmed (or verified). The 11-bit address is multiplexed into this port as specified by P0.0/ASEL.
Reset: A high on this pin for two machine cycles while the oscillator is running resets the device. An
internal diffused resistor to V
After the device is reset, a 10-bit serial sequence, sent LSB first, applied to RESET, places the device
in the programming state allowing programming address, data and V
or verification purposes. The RESET serial sequence must be synchronized with the X1 input.
Crystal 1: Input to the inverting oscillator amplifier and input to the internal clock generator circuits. X1
also serves as the clock to strobe in a serial bit stream into RESET to place the device in the
programming state.
Crystal 2: Output from the inverting oscillator amplifier.
Analog supply voltage and reference input.
Analog supply and reference ground.
PP
(P0.2) – Programming voltage input. (See Note 2.)
IL
). Port 3 also functions as the address input for the EPROM memory location to be
CC
SS
(reference input) cannot differ from V
permits a power-on RESET using only an external capacitor to V
5
NAME AND FUNCTION
CC
PP
by more than 0.2V, and must be
to be applied for programming
83C749/87C749
CC
via a small pullup
Preliminary specification
IL
). Port 1 also
CC
.