Specifications

88
3706C–MICRO–2/11
AT89LP3240/6440
16.2.2 Using Timer 2 to Generate Baud Rates
Timer 2 is selected as the baud rate generator by setting TCLK and/or RCLK in T2CON. Under
these conditions, the baud rates for transmit and receive can be simultaneous ly different by
using Timer 1 for transmit and Timer 2 for receive, or vice versa. The baud rate genera tor mode
is similar to the auto-reload mode, in that a rollover causes the Timer 2 registers to be reloaded
with the 16-bit value in regi
sters RCAP2H a nd RCAP2L, which are preset by software. In this
case, the baud rates in Modes 1 and 3 are determined by Timer 2’s overflow rate according to
the following equation:.
Table 16-3 lists commonly used baud rates and how they can be obtained from Timer 2.
Table 16-2. Commonly Used Baud Rates Generated by Timer 1 (TPS = 0000B)
Baud Rate f
OSC
(MHz) SMOD1
Timer 1
C/T Mode Reload Value
Mode 0: 1 MHz 4 0 X X X
Mode 2: 750K 12 1 X X X
62.5K 12 1 0 2 F4H
38.4K 11.059 0 0 2 F7H
19.2K 11.059 1 0 2 DCH
9.6K 11.059 0 0 2 DCH
4.8K 11.059 0 0 2 B8H
2.4K 11.059 0 0 2 70H
1.2K 11.059 0 0 1 FEE0H
137.5 11.986001F55CH
110 6 0 0 1 F958H
110 12 0 0 1 F304H
Table 16-3. Commonly Used Baud Rates Generated by Timer 2 (TPS = 0000B)
Baud Rate f
OSC
(MHz)
Timer 2
CP/RL2 C/T2 TCLK or RCLK Reload Value
62.5K 12 0 0 1 FFF4H
19.2K 11.059 0 0 1 FFDCH
9.6K 11.059 0 0 1 FFB8H
4.8K 11.059 0 0 1 FF70H
2.4K 11.059 0 0 1 FEE0H
1.2K 11.059 0 0 1 FDC0H
137.5 11.986 0 0 1 EAB8H
110 6 0 0 1 F2AFH
110 12 0 0 1 E55EH
Modes 1 and 3
Baud Rate
1
16
------
Oscillator Frequency
65536 RCAP2H,RCAP2L()–[]
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1
TPS 1+
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××=