Microcontroller

www.DataSheet4U.com Features • Utilizes the AVR® RISC Architecture • AVR – High-performance and Low-power RISC Architecture – 118 Powerful Instructions – Most Single Clock Cycle Execution – 32 x 8 General-purpose Working Registers – Up to 1.5 MIPS Throughput at 1.5 MHz Data and Nonvolatile Program Memory – 8K Bytes Flash Program Memory Endurance: 1,000 Write/Erase Cycles – 256 Bytes Internal SRAM – 512 Bytes EEPROM Endurance: 100,000 Write/Erase Cycles – Programming Lock for Flash Program and EEPROM Data Security Peripheral Features – One 8-bit Timer/Counter with Separate Prescaler – One 16-bit Timer/Counter with Separate Prescaler Special Microcontroller Features – Low-power Idle and Power-down Modes – External and Internal Interrupt Sources – 6-channel, 10-bit ADC Specifications – Low-power, High-speed CMOS Process Technology – Fully Static Operation Power Consumption at 1.5 MHz, 3.6V, 25°C – Active: 1.2 mA – Idle Mode: 0.2 mA – Power-down Mode: <10 µA I/O and Packages – Seven General Output Lines – Two External Interrupt Lines – 48-lead LQFP/VQFP Package Operating Voltage – 3.3 - 6.0V Speed Grade – 0 - 1.5 MHz • • • • • 8-bit Microcontroller with 8K Bytes Programmable Flash AT90C8534 Preliminary • • • Description The AT90C8534 is a low-power CMOS 8-bit microcontroller based on the AVR RISC architecture. By executing powerful instructions in a single clock cycle, the Pin Configuration 48 47 46 45 44 43 42 41 40 39 38 37 NC PA0 PA1 PA2 PA3 NC NC NC NC PA4 PA5 NC (continued) ADIN0 NC NC NC NC NC NC NC NC NC AGND NC 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 36 35 34 33 32 31 30 29 28 27 26 25 NC INT0 INT1 PA6 NC GND NC NC NC NC NC NC ADIN1 ADIN2 ADIN3 ADIN4 ADIN5 AVCC NC RESET NC VCC XTAL2 XTAL1 Rev. 1229B–11/00 1 AT90C8534 achieves throughputs approaching 1 MIPS per MHz allowing the system designer to optimize power consumption versus processing speed. Block Diagram Figure 1. The AT90C8534 Block Diagram PA0 - PA6 INT1,0 VCC PORTA DRIVERS EXTERNAL INTERRUPTS GND DATA REGISTER PORTA DATA DIR. REG. PORTA 8-BIT DATA BUS AVCC ADIN5..0 AGND OSCILLATOR ANALOG MUX ADC XTAL1 XTAL2 PROGRAM COUNTER STACK POINTER TIMING AND CONTROL RESET PROGRAM FLASH SRAM MCU CONTROL REGISTER INSTRUCTION REGISTER GENERAL PURPOSE REGISTERS X Y Z TIMER/ COUNTERS INSTRUCTION DECODER INTERRUPT UNIT CONTROL LINES ALU EEPROM STATUS REGISTER PROGRAMMING LOGIC 2 AT90C8534 AT90C8534 The AVR core combines a rich instruction set with 32 general-purpose working registers. All the 32 registers are directly connected to the Arithmetic Logic Unit (ALU), allowing two independent registers to be accessed in one single instruction executed in one clock cycle. The resulting architecture is more code efficient while achieving throughputs up to ten times faster than conventional CISC microcontrollers. The AT90C8534 provides the following features: 8K bytes of programmable Flash, 512 bytes EEPROM, 256 bytes SRAM, 7 general output lines, 2 external interrupt lines, 32 general-purpose working registers, 2 flexible timer/counters, internal and external interrupts, 6-channel, 10-bit ADC, and 2 software-selectable power saving modes. The Idle mode stops the CPU while allowing the ADC, timer/counters and interrupt system to continue functioning. The Power-down mode saves the SRAM and register contents but freezes the oscillator, disabling all other chip functions until the next interrupt or hardware reset. The device is manufactured using Atmel’s high-density nonvolatile memory technology. The on-chip programmable Flash allows the program memory to be reprogrammed by a conventional nonvolatile memory programmer. By combining an 8-bit RISC CPU with programmable Flash on a monolithic chip, the Atmel AT90C8534 is a powerful microcontroller that provides a highly flexible and cost-effective solution to many embedded control applications. The AT90C8534 AVR is supported with a full suite of program and system development tools including: C compilers, macro assemblers, program debugger/simulators, in-circuit emulators and evaluation kits. Pin Descriptions VCC Digital supply voltage GND Digital ground Port A (PA6..PA0) Port A is a 7-bit output port with tri-state mode. The Port A output buffers can sink 20 mA and can drive LED displays directly. The port pins are tri-stated when a reset condition becomes active, even if the clock is not running. INT1, 0 External interrupt input pins. A falling or rising edge on either of these pins will generate an interrupt request. Interrupt pulses longer than 40 ns will generate an interrupt, even if the clock is not running. ADIN5..0 ADC input pins. Any of these pins can be selected as the input to the ADC. RESET Reset input. An external reset is generated by a low level on the RESET pin. Reset pulses longer than 100 ns will generate a reset, even if the clock is not running. Shorter pulses are not guaranteed to generate a reset. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit. XTAL2 Output from the inverting oscillator amplifier AVCC This is the supply voltage pin for the A/D Converter. If the ADC is not used, the pin must be connected to VCC. If the ADC is used, the pin should be connected to VCC via a low-pass filter. See page 30 for details on operation of the ADC. AGND Analog ground. If the board has a separate analog ground plane, this pin should be connected to this ground plane. Otherwise, connect to GND. 3 Crystal Oscillators XTAL1 and XTAL2 are input and output, respectively, of an inverting amplifier that can be configured for use as an on-chip oscillator, as shown in Figure 2. Either a quartz crystal or a 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 3. Note that XTAL2 should not be used to drive other components. Figure 2. Oscillator Connections Figure 3. External Clock Drive Configuration Architectural Overview The fast-access register file concept contains 32 x 8-bit general-purpose working registers with a single clock cycle access time. This means that during one single clock cycle, one ALU (Arithmetic Logic Unit) operation is executed. Two operands are output from the register file, the operation is executed and the result is stored back in the register file – in one clock cycle. Six of the 32 registers can be used as three 16-bit indirect address register pointers for Data Space addressing, enabling efficient address calculations. One of the three address pointers is also used as the address pointer for the constant table look-up function. These added function registers are the 16-bit X-register, Y-register and Z-register. The ALU supports arithmetic and logic functions between registers or between a constant and a register. Single register operations are also executed in the ALU. Figure 4 shows the AT90C8534 AVR RISC microcontroller architecture. In addition to the register operation, the conventional memory addressing modes can be used on the register file as well. This is enabled by the fact that the register file is assigned the 32 lowermost Data Space addresses ($00 - $1F), allowing them to be accessed as though they were ordinary memory locations. 4 AT90C8534 AT90C8534 The I/O memory space contains 64 addresses for CPU peripheral functions such as Control Registers, Timer/Counters, A/D converters and other I/O functions. The I/O memory can be accessed directly or as the Data Space locations following those of the register file, $20 - $5F. The AVR uses a Harvard architecture concept – with separate memories and buses for program and data. The program memory is executed with a single-level pipelining. While one instruction is being executed, the next instruction is pre-fetched from the program memory. This concept enables instructions to be executed in every clock cycle. The program memory is programmable Flash memory. With the relative jump and call instructions, the whole 4K word (8K bytes) address space is directly accessed. Most AVR instructions have a single 16-bit word format. Every program memory address contains a 16- or 32-bit instruction. During interrupts and subroutine calls, the return address program counter (PC) is stored on the stack. The stack is effectively allocated in the general data SRAM and, consequently, the stack size is only limited by the total SRAM size and the usage of the SRAM. All user programs must initialize the stack pointer (SP) in the reset routine (before subroutines or interrupts are executed). The 9-bit stack pointer is read/write accessible in the I/O space. The 256 bytes data SRAM can be easily accessed through the five different addressing modes supported in the AVR architecture. The memory spaces in the AVR architecture are all linear and regular memory maps. Figure 4. The AT90C8534 AVR RISC Architecture AVR AT90C8534 Architecture Data Bus 8-bit 4K X 16 Program Memory Program Counter Interrupt Unit Instruction Register 32 x 8 General Purpose Registrers Status and Control Indirect Addressing Direct Addressing Instruction Decoder ALU 8-bit Timer/Counter Control Lines 16-bit Timer/Counter 256 x 8 Data SRAM Analog to Digital Converter 512 x 8 EEPROM 7 Output Lines 5 Figure 5. Memory Maps Program Memory $000 Data Memory 32 Gen. Purpose $0000 Working Registers $001F $0020 64 I/O Registers Program Flash (4K x 16) $005F $0060 Internal SRAM (256 x 8) $015F $FFF A flexible interrupt module has its control registers in the I/O space with an additional global interrupt enable bit in the status register. All the different interrupts have a separate interrupt vector in the interrupt vector table at the beginning of the program memory. The different interrupts have priority in accordance with their interrupt vector position. The lower the interrupt vecto