P80C32EBBB PHILIPS [NXP Semiconductors], P80C32EBBB Datasheet - Page 42

• Manufacturer Part Number: P80C32EBBB
• Description: CMOS single-chip 8-bit microcontrollers
• Manufacturer: PHILIPS [NXP Semiconductors]

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
3. POF not present in 80C52.
Philips Semiconductors
When Timer 2 is in the baud rate generator mode, one should not try
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:
If Timer 2 is being clocked internally, the baud rate is:
Where f
Table 4. Timer 2 as a Timer
Table 5. Timer 2 as a Counter
NOTES:
1996 Aug 16
CMOS single-chip 8-bit microcontrollers
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
Baud Rate
OSC
= Oscillator Frequency
[32
Timer 2 Overflow Rate
[65536
16
MODE
MODE
MODE
MODE
(RCAP2H, RCAP2L)]]
f
OSC
12
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 4 for set-up
of Timer 2 as a timer. Also see Table 5 for set-up of Timer 2 as a
counter.
POWER OFF FLAG
The Power Off Flag (POF) is set by on-chip circuitry when the V
level on the 80C54/80C58 rises from 0 to 5V. The POF bit can be
set or cleared by software allowing a user to determine if the reset is
the result of a power-on or a warm start after powerdown. The V
level must remain above 3V for the POF to remain unaffected by the
V
INTERNAL CONTROL
INTERNAL CONTROL
CC
RCAP2H, RCAP2L
level.
(Note 1)
(Note 1)
00H
01H
34H
24H
14H
02H
03H
3
65536
T2CON
TMOD
80C52/80C54/80C58
EXTERNAL CONTROL
EXTERNAL CONTROL
32
Baud Rate
f
OSC
(Note 2)
(Note 2)
0AH
0BH
08H
09H
36H
26H
16H
Product specification
CC
CC