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P80C32EFBB View Datasheet(PDF) - Philips Electronics

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P80C32EFBB
Philips
Philips Electronics Philips
P80C32EFBB Datasheet PDF : 62 Pages
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Philips Semiconductors
CMOS single-chip 8-bit microcontrollers
Product specification
80C52/80C54/80C58
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:
Baud
Rate
+
Timer
2
Overflow
16
Rate
If Timer 2 is being clocked internally, the baud rate is:
Baud Rate + [32
fOSC
[65536 * (RCAP2H, RCAP2L)]]
Where fOSC= Oscillator Frequency
Table 4. Timer 2 as a Timer
MODE
16-bit Auto-Reload
16-bit Capture
Baud rate generator receive and transmit same baud rate
Receive only
Transmit only
To obtain the reload value for RCAP2H and RCAP2L, the above
equation can be rewritten as:
ǒ Ǔ RCAP2H, RCAP2L + 65536 * 32
fOSC
Baud Rate
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 FLAG3
The Power Off Flag (POF) is set by on-chip circuitry when the VCC
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 VCC
level must remain above 3V for the POF to remain unaffected by the
VCC level.
INTERNAL CONTROL
(Note 1)
00H
01H
34H
24H
14H
T2CON
EXTERNAL CONTROL
(Note 2)
08H
09H
36H
26H
16H
Table 5. Timer 2 as a Counter
MODE
16-bit
Auto-Reload
INTERNAL CONTROL
(Note 1)
02H
03H
TMOD
EXTERNAL CONTROL
(Note 2)
0AH
0BH
NOTES:
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
generator mode.
3. POF not present in 80C52.
1996 Aug 16
12
 

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