AT89C52-33PI Atmel, AT89C52-33PI Datasheet - Page 5

• Manufacturer Part Number: AT89C52-33PI
• Description: IC 8051 MCU FLASH 8K 40DIP
• Manufacturer: Atmel
• Series: 89Cr

Specifications of AT89C52-33PI

• Core Processor: 8051
• Core Size: 8-Bit
• Speed: 33MHz
• Connectivity: SIO, UART/USART
• Number Of I /o: 32
• Program Memory Size: 8KB (8K x 8)
• Program Memory Type: FLASH
• Ram Size: 256 x 8
• Voltage - Supply (vcc/vdd): 4 V ~ 6 V
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 40-DIP (0.600", 15.24mm)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Eeprom Size: -
• Data Converters: -
• Peripherals: -

Special Function Registers
A map of the on-chip memory area called the Special Func-
tion Register (SFR) space is shown in Table 1.
Note that not all of the addresses are occupied, and unoc-
cupied addresses may not be implemented on the chip.
Read accesses to these addresses will in general return
random data, and write accesses will have an indetermi-
nate effect.
User software should not write 1s to these unlisted loca-
tions, since they may be used in future products to invoke
Table 2. T2CON – Timer/Counter 2 Control Registe
Data Memory
The AT89C52 implements 256 bytes of on-chip RAM. The
upper 128 bytes occupy a parallel address space to the
Special Function Registers. That means the upper 128
bytes have the same addresses as the SFR space but are
physically separate from SFR space.
When an instruction accesses an internal location above
address 7FH, the address mode used in the instruction
Symbol
TF2
EXF2
RCLK
TCLK
EXEN2
TR2
C/T2
CP/RL2
T2CON Address = 0C8H
Bit Addressable
Bit
TF2
Function
Timer 2 overflow flag set by a Timer 2 overflow and must be cleared by software. TF2 will not be set when either
RCLK = 1 or TCLK = 1.
Timer 2 external flag set when either a capture or reload is caused by a negative transition on T2EX and
EXEN2 = 1. When Timer 2 interrupt is enabled, EXF2 = 1 will cause the CPU to vector to the Timer 2 interrupt
routine. EXF2 must be cleared by software. EXF2 does not cause an interrupt in up/down counter mode
(DCEN = 1).
Receive clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its receive clock in serial
port Modes 1 and 3. RCLK = 0 causes Timer 1 overflow to be used for the receive clock.
Transmit clock enable. When set, causes the serial port to use Timer 2 overflow pulses for its transmit clock in serial
port Modes 1 and 3. TCLK = 0 causes Timer 1 overflows to be used for the transmit clock.
if Timer 2 is not being used to clock the serial port. EXEN2 = 0 causes Timer 2 to ignore events at T2EX.
Start/Stop control for Timer 2. TR2 = 1 starts the timer.
Timer or counter select for Timer 2. C/T2 = 0 for timer function. C/T2 = 1 for external event counter (falling edge
triggered).
Capture/Reload select. CP/RL2 = 1 causes captures to occur on negative transitions at T2EX if EXEN2 = 1. CP/RL2
= 0 causes automatic reloads to occur when Timer 2 overflows or negative transitions occur at T2EX when EXEN2
= 1. When either RCLK or TCLK = 1, this bit is ignored and the timer is forced to auto-reload on Timer 2 overflow.
Timer 2 external enable. When set, allows a capture or reload to occur as a result of a negative transition on T2EX
7
EXF2
6
RCLK
5
TCLK
4
new features. In that case, the reset or inactive values of
the new bits will always be 0.
Timer 2 Registers Control and status bits are contained in
registers T2CON (shown in Table 2) and T2MOD (shown in
Table 4) for Timer 2. The register pair (RCAP2H, RCAP2L)
are the Capture/Reload registers for Timer 2 in 16-bit cap-
ture mode or 16-bit auto-reload mode.
Interrupt Registers The individual interrupt enable bits are
in the IE register. Two priorities can be set for each of the
six interrupt sources in the IP register.r
specifies whether the CPU accesses the upper 128 bytes
of RAM or the SFR space. Instructions that use direct
addressing access SFR space.
For example, the following direct addressing instruction
accesses the SFR at location 0A0H (which is P2).
EXEN2
3
MOV 0A0H, #data
TR2
2
Reset Value = 0000 0000B
C/T2
1
CP/RL2
0
5