P87C52SBPN,112 NXP Semiconductors, P87C52SBPN,112 Datasheet - Page 14

• Manufacturer Part Number: P87C52SBPN,112
• Description: IC 80C51 MCU 8K OTP 40-DIP
• Manufacturer: NXP Semiconductors
• Series: 87Cr

Specifications of P87C52SBPN,112

• Program Memory Type: OTP
• Program Memory Size: 8KB (8K x 8)
• Package / Case: 40-DIP (0.600", 15.24mm)
• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 16MHz
• Connectivity: EBI/EMI, UART/USART
• Peripherals: POR
• Number Of I /o: 32
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Oscillator Type: Internal
• Operating Temperature: 0°C ~ 70°C
• Processor Series: P87C5x
• Core: 80C51
• Data Bus Width: 8 bit
• Data Ram Size: 256 B
• Interface Type: UART
• Maximum Clock Frequency: 33 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 3
• Operating Supply Voltage: 2.7 V to 5.5 V
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Data Converters: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• Other names: 568-1012-5; 935253690112; P87C52SBPN

When Timer 2 is in the baud rate generator mode, one should not try
Philips Semiconductors
Baud Rate Generator Mode
Bits TCLK and/or RCLK in T2CON (Table 3) allow the serial port
transmit and receive baud rates to be derived from either Timer 1 or
Timer 2. When TCLK= 0, Timer 1 is used as the serial port transmit
baud rate generator. When TCLK= 1, Timer 2 is used as the serial
port transmit baud rate generator. RCLK has the same effect for the
serial port receive baud rate. With these two bits, the serial port can
have different receive and transmit baud rates – one generated by
Timer 1, the other by Timer 2.
Figure 6 shows the Timer 2 in baud rate generation mode. The baud
rate generation mode is like the auto-reload mode, in that a rollover
in TH2 causes the Timer 2 registers to be reloaded with the 16-bit
value in registers RCAP2H and RCAP2L, which are preset by
software.
The baud rates in modes 1 and 3 are determined by Timer 2’s
overflow rate given below:
The timer can be configured for either “timer” or “counter” operation.
In many applications, it is configured for “timer” operation (C/T2*=0).
Timer operation is different for Timer 2 when it is being used as a
baud rate generator.
Usually, as a timer it would increment every machine cycle (i.e., 1/12
the oscillator frequency). As a baud rate generator, it increments
every state time (i.e., 1/2 the oscillator frequency). Thus the baud
rate formula is as follows:
Where: (RCAP2H, RCAP2L)= The content of RCAP2H and
RCAP2L taken as a 16-bit unsigned integer.
The Timer 2 as a baud rate generator mode shown in Figure 6, is
valid only if RCLK and/or TCLK = 1 in T2CON register. Note that a
rollover in TH2 does not set TF2, and will not generate an interrupt.
Thus, the Timer 2 interrupt does not have to be disabled when
Timer 2 is in the baud rate generator mode. Also if the EXEN2
(T2 external enable flag) is set, a 1-to-0 transition in T2EX
(Timer/counter 2 trigger input) will set EXF2 (T2 external flag) but
will not cause a reload from (RCAP2H, RCAP2L) to (TH2,TL2).
Therefore when Timer 2 is in use as a baud rate generator, T2EX
can be used as an additional external interrupt, if needed.
to read or write TH2 and TL2. As a baud rate generator, Timer 2 is
incremented every state time (osc/2) or asynchronously from pin T2;
2000 Aug 07
80C51 8-bit microcontroller family
4 K/8 K OTP/ROM low voltage (2.7 V–5.5 V),
low power, high speed (33 MHz), 128/256 B RAM
Modes 1 and 3 Baud Rates + Timer 2 Overflow Rate
Modes 1 and 3 Baud Rates =
[32
[65536 * (RCAP2H, RCAP2L)]]
Oscillator Frequency
16
14
under these conditions, a read or write of TH2 or TL2 may not be
accurate. The RCAP2 registers may be read, but should not be
written to, because a write might overlap a reload and cause write
and/or reload errors. The timer should be turned off (clear TR2)
before accessing the Timer 2 or RCAP2 registers.
Table 4 shows commonly used baud rates and how they can be
obtained from Timer 2.
Table 4.
Summary Of Baud Rate Equations
Timer 2 is in baud rate generating mode. If Timer 2 is being clocked
through pin T2(P1.0) the baud rate is:
If Timer 2 is being clocked internally, the baud rate is:
Where f
To obtain the reload value for RCAP2H and RCAP2L, the above
equation can be rewritten as:
Timer/Counter 2 Set-up
Except for the baud rate generator mode, the values given for
T2CON do not include the setting of the TR2 bit. Therefore, bit TR2
must be set, separately, to turn the timer on. See Table 5 for set-up
of Timer 2 as a timer. Also see Table 6 for set-up of Timer 2 as a
counter.
Ba d Rate
Baud Rate
Baud Rate + Timer 2 Overflow Rate
Baud Rate +
RCAP2H, RCAP2L + 65536 *
375 K
9.6 K
2.8 K
2.4 K
1.2 K
300
300
110
110
OSC
= Oscillator Frequency
Timer 2 Generated Commonly Used
Baud Rates
80C51/87C51/80C52/87C52
[32
Osc Freq
Osc Freq
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
6 MHz
6 MHz
[65536 * (RCAP2H, RCAP2L)]]
16
f
OSC
32
RCAP2H
FD
FF
FF
FF
FF
FE
FB
F2
F9
Baud Rate
f
OSC
Timer 2
Product specification
RCAP2L
FF
D9
B2
C8
1E
AF
8F
64
57