P89C54X2BA NXP Semiconductors, P89C54X2BA Datasheet - Page 20

• Manufacturer Part Number: P89C54X2BA
• Manufacturer: NXP Semiconductors

Specifications of P89C54X2BA

• Cpu Family: 89C
• Device Core: 80C51
• Device Core Size: 8b
• Frequency (max): 20MHz
• Interface Type: UART
• Program Memory Type: Flash
• Program Memory Size: 16KB
• Total Internal Ram Size: 256Byte
• # 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: Compliant

Philips Semiconductors
Table 5.
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:
To obtain the reload value for RCAP2H and RCAP2L, the above
equation can be rewritten as:
2002 Jun 06
80C51 8-bit Flash microcontroller family
4K/8K/16K/32K Flash
n = 16 in 6-clock mode, 32 in 12-clock mode.
f
12-clk
Baud Rate + Timer 2 Overflow Rate
Baud Rate +
RCAP2H, RCAP2L + 65536 *
mode
375 K
OSC
9.6 K
4.8 K
2.4 K
1.2 K
300
110
300
110
Baud Rate
= Oscillator Frequency
Timer 2 Generated Commonly Used
Baud Rates
19.2 K
mode
750 K
6-clk
9.6 K
4.8 K
2.4 K
[n
600
220
600
220
[65536 * (RCAP2H, RCAP2L)]]
Osc Freq
16
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
12 MHz
6 MHz
6 MHz
f
OSC
n
Baud Rate
f
RCAP2H
OSC
FD
FF
FF
FF
FF
FE
FB
F2
F9
Timer 2
RCAP2L
FF
D9
B2
C8
1E
AF
8F
64
57
20
1. Capture/reload occurs only on timer/counter overflow.
2. Capture/reload occurs on timer/counter overflow and a 1-to-0
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 6 for set-up
of Timer 2 as a timer. Also see Table 7 for set-up of Timer 2 as a
counter.
Table 6. Timer 2 as a Timer
Table 7. Timer 2 as a Counter
NOTES:
MODE
16-bit Auto-Reload
16-bit Capture
Baud rate generator receive
and transmit same baud rate
Receive only
Transmit only
MODE
16-bit
Auto-Reload
transition on T2EX (P1.1) pin except when Timer 2 is used in the
baud rate generator mode.
P89C51X2/52X2/54X2/58X2
INTERNAL
CONTROL
(Note 1)
00H
01H
34H
24H
14H
INTERNAL
CONTROL
(Note 1)
02H
03H
T2CON
TMOD
EXTERNAL
CONTROL
(Note 2)
08H
09H
36H
26H
16H
EXTERNAL
CONTROL
(Note 2)
Preliminary data
0AH
0BH