AT89C4051AT89C4051, █ Układy Scalone
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Features • Compatible with MCS ® 51 Products • 4K Bytes of Reprogrammable Flash Memory – Endurance: 1,000 Write/Erase Cycles • 2.7V to 6V Operating Range • Fully Static Operation: 0 Hz to 24 MHz • Two-level Program Memory Lock • 128 x 8-bit Internal RAM • 15 Programmable I/O Lines • Two 16-bit Timer/Counters • Six Interrupt Sources • Programmable Serial UART Channel • Direct LED Drive Outputs • On-chip Analog Comparator • Low-power Idle and Power-down Modes • Brown-out Detection • Power-On Reset (POR) • Green (Pb/Halide-free/RoHS Compliant) Packaging 8-bit Microcontroller with 4K Bytes Flash AT89C4051 1. Description The AT89C4051 is a low-voltage, high-performance CMOS 8-bit microcontroller with 4K bytes of Flash programmable and erasable read-only memory. The device is man- ufactured using Atmel’s high-density nonvolatile memory technology and is compatible with the industry-standard MCS-51 instruction set. By combining a versa- tile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C4051 is a powerful microcontroller which provides a highly-flexible and cost-effective solution to many embedded control applications. The AT89C4051 provides the following standard features: 4K bytes of Flash, 128 bytes of RAM, 15 I/O lines, two 16-bit timer/counters, a five-vector, two-level inter- rupt architecture, a full duplex serial port, a precision analog comparator, on-chip oscillator and clock circuitry. In addition, the AT89C4051 is designed with static logic for operation down to zero frequency and supports two software-selectable power saving modes. The Idle Mode stops the CPU while allowing the RAM, timer/counters, serial port and interrupt system to continue functioning. The power-down mode saves the RAM contents but freezes the oscillator disabling all other chip functions until the next hardware reset. 1001E–MICRO–6/05 2. Pin Configuration 2.1 PDIP/SOIC RST/VPP (RXD) P3.0 (TXD) P3.1 XTAL2 XTAL1 (INT0) P3.2 (INT1) P3.3 (TO) P3.4 (T1) P3.5 GND 1 2 3 4 5 6 7 8 9 10 20 19 18 17 16 15 14 13 12 11 VCC P1.7 P1.6 P1.5 P1.4 P1.3 P1.2 P1.1 (AIN1) P1.0 (AIN0) P3.7 3. Block Diagram 2 AT89C4051 1001E–MICRO–6/05 AT89C4051 4. Pin Description 4.1 VCC Supply voltage. 4.2 GND Ground. 4.3 Port 1 Port 1 is an 8-bit bi-directional I/O port. Port pins P1.2 to P1.7 provide internal pullups. P1.0 and P1.1 require external pullups. P1.0 and P1.1 also serve as the positive input (AIN0) and the neg- ative input (AIN1), respectively, of the on-chip precision analog comparator. The Port 1 output buffers can sink 20 mA and can drive LED displays directly. When 1s are written to Port 1 pins, they can be used as inputs. When pins P1.2 to P1.7 are used as inputs and are externally pulled low, they will source current (I IL ) because of the internal pullups. Port 1 also receives code data during Flash programming and verification. 4.4 Port 3 Port 3 pins P3.0 to P3.5, P3.7 are seven bi-directional I/O pins with internal pullups. P3.6 is hard-wired as an input to the output of the on-chip comparator and is not accessible as a gen- eral-purpose I/O pin. The Port 3 output buffers can sink 20 mA. When 1s are written to Port 3 pins they are pulled high by the internal pullups and can be used as inputs. As inputs, Port 3 pins that are externally being pulled low will source current (I IL ) because of the pullups. Port 3 also serves the functions of various special features of the AT89C4051 as listed below: Port Pin Alternate Functions P3.0 RXD (serial input port) P3.1 TXD (serial output port) P3.2 INT0 (external interrupt 0) P3.3 INT1 (external interrupt 1) P3.4 T0 (timer 0 external input) P3.5 T1 (timer 1 external input) Port 3 also receives some control signals for Flash programming and verification. 4.5 RST Reset input. All I/O pins are reset to 1s as soon as RST goes high. Holding the RST pin high for two machine cycles while the oscillator is running resets the device. Each machine cycle takes 12 oscillator or clock cycles. 4.6 XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. 3 1001E–MICRO–6/05 4.7 XTAL2 Output from the inverting oscillator amplifier. 5. Oscillator Characteristics XTAL1 and XTAL2 are the input and output, respectively, of an inverting amplifier which can be configured for use as an on-chip oscillator, as shown in Figure 5-1 . Either a quartz crystal or ceramic resonator may be used. To drive the device from an external clock source, XTAL2 should be left unconnected while XTAL1 is driven as shown in Figure 5-2 . There are no require- ments on the duty cycle of the external clock signal, since the input to the internal clocking circuitry is through a divide-by-two flip-flop, but minimum and maximum voltage high and low time specifications must be observed. Figure 5-1. Oscillator Connections Note: C1, C2 = 30 pF = 40 pF ± 10 pF for Ceramic Resonators ± 10 pF for Crystals Figure 5-2. External Clock Drive Configuration 4 AT89C4051 1001E–MICRO–6/05 AT89C4051 6. Special Function Registers A map of the on-chip memory area called the Special Function Register (SFR) space is shown in the Table 6-1 . Note that not all of the addresses are occupied, and unoccupied addresses may not be imple- mented on the chip. Read accesses to these addresses will in general return random data, and write accesses will have an indeterminate effect. User software should not write 1s to these unlisted locations, since they may be used in future products to invoke new features. In that case, the reset or inactive values of the new bits will always be 0. Table 6-1. AT89C4051 SFR Map and Reset Values 0F8H 0FFH 0F0H B 00000000 0F7H 0E8H 0EFH 0E0H ACC 00000000 0E7H 0D8H 0DFH 0D0H PSW 00000000 0D7H 0C8H 0CFH 0C0H 0C7H 0B8H IP XXX00000 0BFH 0B0H P3 11111111 0B7H 0A8H IE 0XX00000 0AFH 0A0H 0A7H 98H SCON 00000000 SBUF XXXXXXXX 9FH 90H P1 11111111 97H 88H TCON 00000000 TMOD 00000000 TL0 00000000 TL1 00000000 TH0 00000000 TH1 00000000 8FH 80H SP 00000111 DPL 00000000 DPH 00000000 PCON 0XXX0000 87H 5 1001E–MICRO–6/05 [ Pobierz całość w formacie PDF ] |
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