P89C51RB2HBA NXP Semiconductors, P89C51RB2HBA Datasheet - Page 17

• Manufacturer Part Number: P89C51RB2HBA
• Manufacturer: NXP Semiconductors

Specifications of P89C51RB2HBA

• Cpu Family: 89C
• Device Core: 80C51
• Device Core Size: 8b
• Frequency (max): 33MHz
• Interface Type: UART
• Program Memory Type: Flash
• Program Memory Size: 16KB
• Total Internal Ram Size: 512Byte
• # I/os (max): 32
• Number Of Timers - General Purpose: 3
• Operating Supply Voltage (typ): 5V
• Operating Supply Voltage (max): 5.5V
• Operating Supply Voltage (min): 4.5V
• Instruction Set Architecture: CISC
• Operating Temp Range: 0C to 70C
• Operating Temperature Classification: Commercial
• Mounting: Surface Mount
• Pin Count: 44
• Package Type: PLCC
• Lead Free Status / Rohs Status: Not Compliant

When Timer 2 is in the baud rate generator mode, one should not try
1. Capture/reload occurs only on timer/counter overflow.
2. Capture/reload occurs on timer/counter overflow and a 1-to-0 transition on T2EX (P1.1) pin except when Timer 2 is used in the baud rate
Philips Semiconductors
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;
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 3 shows commonly used baud rates and how they can be
obtained from Timer 2.
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:
Table 4.
Table 5.
NOTES:
2002 May 24
80C51 8-bit Flash microcontroller family
16KB/32KB/64KB ISP/IAP Flash with 512B/512B/1KB RAM
16-bit Auto-Reload
16-bit Capture
Baud rate generator receive and transmit same baud rate
Receive only
Transmit only
16-bit
Auto-Reload
generator mode.
Baud Rate + Timer 2 Overflow Rate
Timer 2 as a Timer
Timer 2 as a Counter
16
MODE
MODE
14
Except for the baud rate generator mode, the values given for T2CON
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
do not include the setting of the TR2 bit. Therefore, bit TR2 must be
set, separately, to turn the timer on. see Table 4 for set-up of Timer 2
as a timer. Also see Table 5 for set-up of Timer 2 as a counter.
INTERNAL CONTROL
INTERNAL CONTROL
Baud Rate +
RCAP2H, RCAP2L + 65536 +
(Note 1)
(Note 1)
OSC
00H
01H
34H
24H
14H
02H
03H
= Oscillator Frequency
[ n *
* n =
P89C51RB2/P89C51RC2/
[65536 + (RCAP2H, RCAP2L)]]
T2CON
TMOD
16 in 6 clock mode
32 in 12 clock mode
f
OSC
P89C51RD2Hxx
EXTERNAL CONTROL
EXTERNAL CONTROL
n *
Baud Rate
f
OSC
(Note 2)
(Note 2)
0AH
0BH
08H
09H
36H
26H
16H
Product data