Features
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80C51 Core Architecture 256 Bytes of On-chip RAM 1 KB of On-chip XRAM 32 KB of On-chip Flash Memory – Data Retention: 10 Years at 85°C Read/Write Cycle: 10K 2 KB of On-chip Flash for Bootloader 2 KB of On-chip EEPROM Read/Write Cycle: 100K 14-sources 4-level Interrupts Three 16-bit Timers/Counters Full Duplex UART Compatible 80C51 Maximum Crystal Frequency 40 MHz, in X2 Mode, 20 MHz (CPU Core, 20 MHz) Five Ports: 32 + 2 Digital I/O Lines Five-channel 16-bit PCA with: – PWM (8-bit) – High-speed Output – Timer and Edge Capture Double Data Pointer 21-bit Watchdog Timer (7 Programmable Bits) 10-bit Resolution Analog to Digital Converter (ADC) with 8 Multiplexed Inputs On-chip Emulation Logic (Enhanced Hook System) Power Saving Modes: – Idle Mode – Power-down Mode Power Supply: 3V to 5.5V Temperature Range: Industrial (-40° to +85°C) Packages: VQFP44, PLCC44
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Enhanced 8-bit Microcontroller with 32 KB Flash Memory
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AT89C51AC2 T89C51AC2
Description
The A/T89C51AC2 is a high performance Flash version of the 80C51 single chip 8-bit microcontrollers. It contains a 32 KB Flash memory block for program and data. The 32 KB Flash memory can be programmed either in parallel mode or in serial mode with the ISP capability or with software. The programming voltage is internally generated from the standard VCC pin. The A/T89C51AC2 retains all features of the 80C51 with 256 bytes of internal RAM, a 7-source 4-level interrupt controller and three timer/counters. In addition, the A/T89C51AC2 has a 10-bit A/D converter, a 2 KB Boot Flash memory, 2 KB EEPROM for data, a Programmable Counter Array, an XRAM of 1024 bytes, a Hardware WatchDog Timer, and a more versatile serial channel that facilitates multiprocessor communication (EUART). The fully static design of the A/T89C51AC2 reduces system power consumption by bringing the clock frequency down to any value, even DC, without loss of data. The A/T89C51AC2 has two software-selectable modes of reduced activity and an 8bit clock prescaler for further reduction in power consumption. In the idle mode the CPU is frozen while the peripherals and the interrupt system are still operating. In the Power-down mode the RAM is saved and all other functions are inoperative. The added features of the A/T89C51AC2 make it more powerful for applications that need A/D conversion, pulse width modulation, high speed I/O and counting capabilities such as industrial control, consumer goods, alarms, motor control, among others. While remaining fully compatible with the 80C52, the T8C51AC2 offers a superset of this standard microcontroller. In X2 mode, a maximum external clock rate of 20 MHz reaches a 300 ns cycle time.
Rev. 4127G–8051–05/06
1
Block Diagram
T2EX VAVCC VAREF RxD TxD Vcc Vss PCA ECI T2 VAGND
XTAL1 XTAL2 ALE PSEN CPU EA RD WR Timer 0 Timer 1 INT Ctrl Parallel I/O Ports and Ext. Bus Watch Dog Port 0 Port 1 Port 2 Port 3 Port 4 10 bit ADC UART RAM 256x8
C51 CORE
Flash Boot EE 32kx loader PROM 8 2kx8 2kx8
XRAM
1kx8
PCA
Timer 2
IB-bus
P1(1)
RESET
INT0
Notes:
1. 8 analog Inputs/8 Digital I/O 2. 2-Bit I/O Port
2
A/T89C51AC2
4127G–8051–05/06
INT1
P4(2)
P2
T0
T1
P0
P3
A/T89C51AC2
Pin Configuration
P1.3/AN3/CEX0 P1.2/AN2/ECI P1.1/AN1/T2EX P1.0/AN 0/T2 VAREF VAGND RESET VSS VCC XTAL1 XTAL2 P1.4/AN4/CEX1 P1.5/AN5/CEX2 P1.6/AN6/CEX3 P1.7/AN7/CEX4 EA P3.0/RxD P3.1/TxD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1 7 8 9 10 11 12 13 14 15 16 17 6 5 4 3 2 1 44 43 42 41 40 39 38 37 36 35 34 33 32 31 30 29
PLCC44
ALE PSEN P0.7/AD7 P0.6/AD6 P0.5/AD5 P0.4/AD4 P0.3/AD3 P0.2/AD2 P0.1/AD1 P0.0/AD0 P2.0/A8
44 43 42 41 40 39 38 37 36 35 34
P1.3/AN3/CEX0 P1.2/AN2/ECI P1.1/AN1/T2EX P1.0/AN 0/T2 VAREF VAGND RESET VSS VCC XTAL1 XTAL2
P3.6/WR P3.7/RD P4.0 P4.1 P2.7/A15 P2.6/A14 P2.5/A13 P2.4/A12 P2.3/A11 P2.2/A10 P2.1/A9
18 19 20 21 22 23 24 25 26 27 28
P1.4/AN4/CEX1 P1.5/AN5/CEX2 P1.6/AN6/CEX3 P1.7/AN7/CEX4 EA P3.0/RxD P3.1/TxD P3.2/INT0 P3.3/INT1 P3.4/T0 P3.5/T1
1 2 3 4 5 6 7 8 9 10 11
33 32 31 30 29 28 27 26 25 24 23
VQFP44
ALE PSEN P0.7/AD7 P0.6/AD6 P0.5/AD5 P0.4 /AD4 P0.3 /AD3 P0.2 /AD2 P0.1 /AD1 P0.0 /AD0 P2.0/A8
12 13 14 15 16 17 18 19 20 21 22
P3.6/WR P3.7/RD P4.0 P4.1 P2.7/A15 P2.6/A14 P2.5/A13 P2.4/A12 P2.3/A11 P2.2/A10 P2.1/A9
3
4127G–8051–05/06
Table 1. Pin Description
Pin Name VSS VCC VAREF VAGND P0.0:7 I/O Type GND Description Circuit ground Supply Voltage Reference Voltage for ADC Reference Ground for ADC Port 0: Is an 8-bit open drain bi-directional I/O port. Port 0 pins that have 1’s written to them float, and in this state can be used as high-impedance inputs. Port 0 is also the multiplexed low-order address and data bus during accesses to external Program and Data Memory. In this application it uses strong internal pull-ups when emitting 1’s. Port 0 also outputs the code Bytes during program validation. External pull-ups are required during program verification. Port 1: Is an 8-bit bi-directional I/O port with internal pull-ups. Port 1 pins can be used for digital input/output or as analog inputs for the Analog Digital Converter (ADC). Port 1 pins that have 1’s written to them are pulled high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 1 pins that are being pulled low externally will be the source of current (IIL, see section "Electrical Characteristic") because of the internal pull-ups. Port 1 pins are assigned to be used as analog inputs via the ADCCF register (in this case the internal pull-ups are disconnected). As a secondary digital function, port 1 contains the Timer 2 external trigger and clock input; the PCA external clock input and the PCA module I/O. P1.0/AN0/T2 Analog input channel 0, External clock input for Timer/counter2. P1.1/AN1/T2EX Analog input channel 1, Trigger input for Timer/counter2. P1.2/AN2/ECI Analog input channel 2, PCA external clock input. P1.3/AN3/CEX0 Analog input channel 3, PCA module 0 Entry of input/PWM output. P1.4/AN4/CEX1 Analog input channel 4, PCA module 1 Entry of input/PWM output. P1.5/AN5/CEX2 Analog input channel 5, PCA module 2 Entry of input/PWM output. P1.6/AN6/CEX3 Analog input channel 6, PCA module 3 Entry of input/PWM output. P1.7/AN7/CEX4 Analog input channel 7, PCA module 4 Entry ot input/PWM output. Port 1 receives the low-order address byte during EPROM programming and program verification. It can drive CMOS inputs without external pull-ups. P2.0:7 I/O Port 2: Is an 8-bit bi-directional I/O port with internal pull-ups. Port 2 pins that have 1’s written to them are pulled high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 2 pins that are being pulled low externally will be a source of current (IIL, see section "Electrical Characteristic") because of the internal pull-ups. Port 2 emits the high-order address byte during accesses to the external Program Memory and during accesses to external Data Memory that uses 16-bit addresses (MOVX @DPTR). In this application, it uses strong internal pull-ups when emitting 1’s. During accesses to external Data Memory that use 8 bit addresses (MOVX @Ri), Port 2 transmits the contents of the P2 special function register. It also receives high-order addresses and control signals during program validation. It can drive CMOS inputs without external pull-ups.
P1.0:7
I/O
4
A/T89C51AC2
4127G–8051–05/06
A/T89C51AC2
Table 1. Pin Description (Continued)
Pin Name P3.0:7 Type I/O Description Port 3: Is an 8-bit bi-directional I/O port with internal pull-ups. Port 3 pins that have 1’s written to them are pulled high by the internal pull-up transistors and can be used as inputs in this state. As inputs, Port 3 pins that are being pulled low externally will be a source of current (IIL , see section "Electrical Characteristic") because of the internal pull-ups. The output latch corresponding to a secondary function must be programmed to one for that function to operate (except for TxD and WR). The secondary functions are assigned to the pins of port 3 as follows: P3.0/RxD: Receiver data input (asynchronous) or data input/output (synchronous) of the serial interface P3.1/TxD: Transmitter data output (asynchronous) or clock output (synchronous) of the serial interface P3.2/INT0: External interrupt 0 input/timer 0 gate control input P3.3/INT1: External interrupt 1 input/timer 1 gate control input P3.4/T0: Timer 0 counter input P3.5/T1: Timer 1 counter input P3.6/WR: External Data Memory write strobe; latches the data byte from port 0 into the external data memory P3.7/RD: External Data Memory read strobe; Enables the external data memory. It can drive CMOS inputs without external pull-ups. P4.0:1 I/O Port 4: Is an 2-bit bi-directional I/O port with internal pull-ups. Port 4 pins that have 1’s written to them are pulled high by the internal pull-ups and can be used as inputs in this state. As inputs, Port 4 pins that are being pulled low externally will be a source of current (IIL, on the datasheet) because of the internal pull-up transistor. P4.0 P4.1: It can drive CMOS inputs without external pull-ups. Reset: A high level on this pin during two machine cycles while the oscillator is running resets the device. An internal pull-down resistor to VSS permits power-on reset using only an external capacitor to VCC. ALE: An Address Latch Enable output for latching the low byte of the address during accesses to the external memory. The ALE is activated every 1/6 oscillator periods (1/3 in X2 mode) except during an external data memory access. When instructions are executed from an internal Flash (EA = 1), ALE generation can be disabled by the software. PSEN: The Program Store Enable output is a control signal that enables the external program memory of the bus during external fetch operations. It is activated twice each machine cycle during fetches from the external program
