AT89C5132 Atmel Corporation, AT89C5132 Datasheet - Page 52
AT89C5132
Manufacturer Part Number
AT89C5132
Description
Manufacturer
Atmel Corporation
Datasheets
1.AT89C5132.pdf
(3 pages)
2.AT89C5132.pdf
(182 pages)
3.AT89C5132.pdf
(38 pages)
4.AT89C5132.pdf
(33 pages)
Specifications of AT89C5132
Flash (kbytes)
64 Kbytes
Max. Operating Frequency
20 MHz
Cpu
8051-12C
Max I/o Pins
44
Usb Transceiver
1
Usb Speed
Full Speed
Usb Interface
Device
Spi
1
Uart
1
Adc Channels
2
Adc Resolution (bits)
10
Adc Speed (ksps)
22.7
Sram (kbytes)
2.25
Self Program Memory
API
Operating Voltage (vcc)
2.7 to 3.6
Timers
2
Isp
UART/USB
Watchdog
Yes
Available stocks
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Figure 12-8. Timer/Counter 0 in Mode 3: Two 8-bit Counters
Figure 12-9. Mode 3 Overflow Period Formula
12.4
52
Timer 1
AT89C5132
INT0
CLOCK
CLOCK
TIM0
TIM0
T0
GATE0
TMOD.3
÷ 6
÷ 6
Counter. TL0 uses the Timer 0 control Bits C/T0# and GATE0 in TMOD register, and TR0 and
TF0 in TCON register in the normal manner. TH0 is locked into a Timer function (counting
F
ation of Timer 1 is restricted when Timer 0 is in mode 3. Figure 12-7 gives the autoreload period
calculation formulas for both TF0 and TF1 flags.
Timer 1 is identical to Timer 0 excepted for Mode 3 which is a hold-count mode. Following com-
ments help to understand the differences:
•
•
•
•
•
•
•
TF1
Timer 1 functions as either a Timer or event Counter in three modes of operation. Figure 12-
2 through Figure 12-6 show the logical configuration for modes 0, 1, and 2. Timer 1’s mode
3 is a hold-count mode.
Timer 1 is controlled by the four high-order Bits of TMOD register (see
3, 6 and 7 of TCON register (see Figure 40). TMOD register selects the method of Timer
gating (GATE1), Timer or Counter operation (C/T1#) and mode of operation (M11 and M01).
TCON register provides Timer 1 control functions: overflow flag (TF1), run control bit (TR1),
interrupt flag (IE1) and interrupt type control bit (IT1).
Timer 1 can serve as the Baud Rate Generator for the Serial Port. Mode 2 is best suited for
this purpose.
For normal Timer operation (GATE1 = 0), setting TR1 allows TL1 to be incremented by the
selected input. Setting GATE1 and TR1 allows external pin INT1 to control Timer operation.
Timer 1 overflow (count rolls over from all 1s to all 0s) sets the TF1 flag generating an
interrupt request.
When Timer 0 is in mode 3, it uses Timer 1’s overflow flag (TF1) and run control bit (TR1).
For this situation, use Timer 1 only for applications that do not require an interrupt (such as a
Baud Rate Generator for the Serial Port) and switch Timer 1 in and out of mode 3 to turn it
off and on.
It is important to stop the Timer/Counter before changing modes.
/6) and takes over use of the Timer 1 interrupt (TF1) and run control (TR1) Bits. Thus, oper-
TMOD.2
C/T0#
TF0
0
1
PER
TCON.4
TR0
=
6
⋅
(256 – TL0)
TCON.6
F
TR1
TIM0
(8 Bits)
(8 Bits)
TH0
TL0
TF1
PER
=
6
Overflow
Overflow
⋅
(256 – TH0)
F
TIM0
TCON.5
TCON.7
TF0
TF1
Table
Timer 0
Interrupt
Request
Timer 1
Interrupt
Request
41) and Bits 2,
4173E–USB–09/07