P87LPC762BD NXP Semiconductors, P87LPC762BD Datasheet - Page 25

• Manufacturer Part Number: P87LPC762BD
• Description: MCU 8-Bit 87LP 80C51 CISC 2KB EPROM 5V 20-Pin SO Tube
• Manufacturer: NXP Semiconductors

Specifications of P87LPC762BD

• Package: 20SO
• Device Core: 80C51
• Family Name: 87LP
• Maximum Speed: 20 MHz
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Number Of Programmable I/os: 18
• Interface Type: I2C/UART
• Number Of Timers: 2
• Ram Size: 128 Byte
• Program Memory Size: 2 KB
• Program Memory Type: EPROM
• Operating Temperature: 0 to 70 °C

Philips Semiconductors
Oscillator
The 87LPC762 provides several user selectable oscillator options,
allowing optimization for a range of needs from high precision to
lowest possible cost. These are configured when the EPROM is
Low Frequency Oscillator Option
This option supports an external crystal in the range of 20 kHz to 100 kHz.
Table 5 shows capacitor values that may be used with a quartz crystal in this mode.
Table 5. Recommended oscillator capacitors for use with the low frequency oscillator option
Medium Frequency Oscillator Option
This option supports an external crystal in the range of 100 kHz to 4 MHz. Ceramic resonators are also supported in this configuration.
Table 6 shows capacitor values that may be used with a quartz crystal in this mode.
Table 6. Recommended oscillator capacitors for use with the medium frequency oscillator option
High Frequency Oscillator Option
This option supports an external crystal in the range of 4 to 20 MHz. Ceramic resonators are also supported in this configuration.
Table 7 shows capacitor values that may be used with a quartz crystal in this mode.
Table 7. Recommended oscillator capacitors for use with the high frequency oscillator option
On-Chip RC Oscillator Option
The on-chip RC oscillator option has a typical frequency of 6 MHz
and can be divided down for slower operation through the use of the
DIVM register. Note that some devices have 10% tolerance and
others 25% tolerance at this time. For on-chip oscillator tolerance
see Electrical Characteristics table. A clock output on the X2/P2.0
pin may be enabled when the on-chip RC oscillator is used.
External Clock Input Option
In this configuration, the processor clock is input from an external
source driving the X1/P2.1 pin. The rate may be from 0 Hz up to
20 MHz when V
below 4.5 V. When the external clock input mode is used, the X2/P2.0
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Frequency
Frequency
Oscillator
Oscillator
100 kHz
16 MHz
20 MHz
20 kHz
32 kHz
Oscillator Freq ency
Oscillator Frequency
4 MHz
8 MHz
100 kHz
1 MHz
4 MHz
DD
is above 4.5 V and up to 10 MHz when V
Lower Limit
Lower Limit
15 pF
15 pF
15 pF
15 pF
15 pF
–
–
V
V
DD
DD
Optimal Value
Optimal Value
= 2.7 to 4.5 V
= 2.7 to 4.5 V
Lower Limit
15 pF
15 pF
15 pF
33 pF
15 pF
–
–
33 pF
15 pF
15 pF
DD
is
Upper Limit
Upper Limit
33 pF
33 pF
33 pF
47 pF
33 pF
22
–
–
programmed. Basic oscillator types that are supported include: low,
medium, and high speed crystals, covering a range from 20 kHz to
20 MHz; ceramic resonators; and on-chip RC oscillator.
pin may be used as a standard port pin. A clock output on the X2/P2.0
pin may be enabled when the external clock input is used.
Clock Output
The 87LPC762 supports a clock output function when either the
on-chip RC oscillator or external clock input options are selected.
This allows external devices to synchronize to the 87LPC762. When
enabled, via the ENCLK bit in the P2M1 register, the clock output
appears on the X2/CLKOUT pin whenever the on-chip oscillator is
running, including in Idle mode. The frequency of the clock output is
1/6 of the CPU clock rate. If the clock output is not needed in Idle
mode, it may be turned off prior to entering Idle, saving additional
power. The clock output may also be enabled when the external
clock input option is selected.
V
DD
Optimal Value
= 2.7 to 4.5 V
Lower Limit
Lower Limit
33 pF
15 pF
15 pF
33 pF
33 pF
15 pF
15 pF
15 pF
15 pF
15 pF
V
V
DD
DD
Optimal Value
Optimal Value
= 4.5 to 6.0 V
= 4.5 to 6.0 V
33 pF
33 pF
15 pF
33 pF
33 pF
15 pF
15 pF
Upper Limit
87LPC762
47 pF
33 pF
33 pF
Upper Limit
Upper Limit
Preliminary data
47 pF
47 pF
33 pF
68 pF
47 pF
33 pF
33 pF