P87LPC760BDH NXP Semiconductors, P87LPC760BDH Datasheet - Page 35

• Manufacturer Part Number: P87LPC760BDH
• Description: MCU 8-Bit 87LP 80C51 CISC 1KB EPROM 5V 14-Pin TSSOP Tube
• Manufacturer: NXP Semiconductors

Specifications of P87LPC760BDH

• Package: 14TSSOP
• Device Core: 80C51
• Family Name: 87LP
• Maximum Speed: 20 MHz
• Ram Size: 128 Byte
• Program Memory Size: 1 KB
• Operating Supply Voltage: 5 V
• Data Bus Width: 8 Bit
• Program Memory Type: EPROM
• Number Of Programmable I/os: 12
• Interface Type: I2C/UART
• Operating Temperature: 0 to 70 °C
• Number Of Timers: 2

Philips Semiconductors
Baud Rates
The baud rate in Mode 0 is fixed: Mode 0 Baud Rate = CPU clock/6.
The baud rate in Mode 2 depends on the value of bit SMOD1 in
Special Function Register PCON. If SMOD1 = 0 (which is the value
on reset), the baud rate is 1/32 of the CPU clock frequency. If
SMOD1 = 1, the baud rate is 1/16 of the CPU clock frequency.
Using Timer 1 to Generate Baud Rates
When Timer 1 is used as the baud rate generator, the baud rates in
Modes 1 and 3 are determined by the Timer 1 overflow rate and the
value of SMOD1. The Timer 1 interrupt should be disabled in this
2002 Mar 07
Low power, low price, low pin count (14 pin)
microcontroller with 1 kbyte OTP
SCON
Mode 2 Baud Rate + 1
BIT
SCON.7
SCON.7
SCON. 6
SCON.5
SCON.4
SCON.3
SCON.2
SCON.1
SCON.0
Address: 98h
Bit Addressable
SM0, SM1
SYMBOL
REN
SM0
SM1
SM2
RB8
TB8
FE
0 0
0 1
1 0
1 1
RI
TI
SM0/FE
7
SMOD1
32
FUNCTION
Framing Error. This bit is set by the UART receiver when an invalid stop bit is detected. Must be
cleared by software. The SMOD0 bit in the PCON register must be 1 for this bit to be accessible.
See SM0 bit below.
With SM1, defines the serial port mode. The SMOD0 bit in the PCON register must be 0 for this bit
to be accessible. See FE bit above.
With SM0, defines the serial port mode (see table below).
UART Mode
0: shift register
1: 8-bit UART
2: 9-bit UART
3: 9-bit UART
Enables the multiprocessor communication feature in Modes 2 and 3. In Mode 2 or 3, if SM2 is set
to 1, then Rl will not be activated if the received 9th data bit (RB8) is 0. In Mode 1, if SM2=1 then RI
will not be activated if a valid stop bit was not received. In Mode 0, SM2 should be 0.
Enables serial reception. Set by software to enable reception. Clear by software to disable reception.
The 9th data bit that will be transmitted in Modes 2 and 3. Set or clear by software as desired.
In Modes 2 and 3, is the 9th data bit that was received. In Mode 1, it SM2=0, RB8 is the stop bit that
was received. In Mode 0, RB8 is not used.
Transmit interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or at the beginning
of the stop bit in the other modes, in any serial transmission. Must be cleared by software.
Receive interrupt flag. Set by hardware at the end of the 8th bit time in Mode 0, or halfway through
the stop bit time in the other modes, in any serial reception (except see SM2). Must be cleared by
software.
SM1
x CPU clock frequency
6
Figure 31. Serial Port Control Register (SCON)
SM2
5
REN
Baud Rate
CPU clock/6
Variable (see text)
CPU clock/32 or CPU clock/16
Variable (see text)
4
32
TB8
3
application. The Timer itself can be configured for either “timer” or
“counter” operation, and in any of its 3 running modes. In the most
typical applications, it is configured for “timer” operation, in the
auto-reload mode (high nibble of TMOD = 0010b). In that case the
baud rate is given by the formula:
Tables 6 and 7 list various commonly used baud rates and how they
can be obtained using Timer 1 as the baud rate generator.
RB8
Mode 1, 3 Baud Rate +
2
TI
1
RI
0
192 (or 96 if SMOD1 + 1)
CPU clock frequency
Reset Value: 00h
256 * (TH1)
P87LPC760
Preliminary data
SU01550