AT89C51CC03CA-RLTUM Atmel, AT89C51CC03CA-RLTUM Datasheet - Page 71

• Manufacturer Part Number: AT89C51CC03CA-RLTUM
• Description: IC 8051 MCU 64K FLASH 44-VQFP
• Manufacturer: Atmel
• Series: AT89C CANr

Specifications of AT89C51CC03CA-RLTUM

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 40MHz
• Connectivity: CAN, UART/USART
• Peripherals: POR, PWM, WDT
• Number Of I /o: 36
• Program Memory Size: 64KB (64K x 8)
• Program Memory Type: FLASH
• Eeprom Size: 2K x 8
• Ram Size: 2.25K x 8
• Voltage - Supply (vcc/vdd): 3 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: External
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 44-TQFP, 44-VQFP
• Processor Series: AT89x
• Core: 8051
• Data Bus Width: 8 bit
• Data Ram Size: 2304 B
• Interface Type: UART, SPI
• Maximum Clock Frequency: 60 MHz
• Number Of Programmable I/os: 36
• Number Of Timers: 2
• Operating Supply Voltage: 3 V to 5.5 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: PK51, CA51, A51, ULINK2
• Minimum Operating Temperature: - 40 C
• On-chip Adc: 10 bit, 8 Channel
• Package: 44VQFP
• Device Core: 8051
• Family Name: AT89
• Maximum Speed: 60 MHz
• For Use With: AT89OCD-01 - USB EMULATOR FOR AT8XC51 MCU
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Timer 1
Mode 0 (13-bit Timer)
Mode 1 (16-bit Timer)
Mode 2 (8-bit Timer with Auto-
Reload)
Mode 3 (Halt)
4182O–CAN–09/08
Timer 1 is identical to Timer 0 excepted for Mode 3 which is a hold-count mode. The fol-
lowing comments help to understand the differences:
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Mode 0 configures Timer 1 as a 13-bit Timer, which is set up as an 8-bit Timer (TH1 reg-
ister) with a modulo-32 prescaler implemented with the lower 5 bits of the TL1 register
(see Figure 35). The upper 3 bits of TL1 register are ignored. Prescaler overflow incre-
ments TH1 register.
Mode 1 configures Timer 1 as a 16-bit Timer with TH1 and TL1 registers connected in
cascade (see Figure 36). The selected input increments TL1 register.
Mode 2 configures Timer 1 as an 8-bit Timer (TL1 register) with automatic reload from
TH1 register on overflow (see Figure 37). TL1 overflow sets TF1 flag in TCON register
and reloads TL1 with the contents of TH1, which is preset by software. The reload
leaves TH1 unchanged.
Placing Timer 1 in mode 3 causes it to halt and hold its count. This can be used to halt
Timer 1 when TR1 run control bit is not available i.e. when Timer 0 is in mode 3.
Timer 1 functions as either a Timer or event Counter in three modes of operation.
Figure 35 to Figure 37 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 Figure 31)
and bits 2, 3, 6 and 7 of TCON register (see Figure 30). 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 Timer/Counter before changing mode.
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