Features • Utilizes the ARM7TDMI™ ARM Thumb Processor Core • • • • • • • • • • • • • • • • – High-performance 32-bit RISC Architecture – High-density 16-bit Instruction Set – Leader in MIPS/Watt – Embedded ICE (In-Circuit Emulation) 8K Bytes Internal RAM Fully Programmable External Bus Interface (EBI) – Maximum External Address Space of 64M Bytes – Up to 8 Chip Selects – Software Programmable 8/16-bit External Data Bus 8-channel Peripheral Data Controller 8-level Priority, Individually Maskable, Vectored Interrupt Controller – 5 External Interrupts, Including a High-priority, Low-latency Interrupt Request 54 Programmable I/O Lines 6-channel 16-bit Timer/Counter – 6 External Clock Inputs – 2 Multi-purpose I/O Pins per Channel 2 USARTs – 2 Dedicated Peripheral Data Controller (PDC) Channels per USART – Support for up to 9-bit Data Transfers 2 Master/Slave SPI Interfaces – 2 Dedicated Peripheral Data Controller (PDC) Channels per SPI – 8- to 16-bit Programmable Data Length – 4 External Slave Chip Selects per SPI 3 System Timers: – Period Interval Timer (PIT); Real-time Timer (RTT); Watchdog Timer (WDT) Power Management Controller (PMC) – CPU and Peripherals Can be Deactivated Individually Clock Generator with 32.768 kHz Low-power Oscillator and PLL – Support for 31.25 kHz and 38.4 kHz Crystals – Software Programmable System Clock (up to 33 MHz) IEEE 1149.1 JTAG Boundary Scan on All Active Pins Fully Static Operation: 0 Hz to 33 MHz (17 MHz at 1.8V) 1.8V to 3.6V Core Operating Voltage Range; 2.7V to 5.5V I/O Operating Voltage Range -40°C to +85°C Operating Temperature Range Available in a 144-lead TQFP Package and in 144-ball BGA Package AT91 ARM® Thumb® Microcontrollers AT91M42800 Summary Description The AT91M42800 Microcontroller is a member of the Atmel AT91 16/32-bit Microcontroller family, which is based on the ARM7TDMI processor core. This processor has a high-performance 32-bit RISC architecture with a high-density 16-bit instruction set and very low power consumption. In addition, a large number of internally banked registers result in very fast exception handling, making the device ideal for real-time control applications. The AT91 ARM-based MCU family also features Atmel’s highdensity, in-system programmable, nonvolatile memory technology. The AT91M42800 has a direct connection to off-chip memory, including Flash, through the External Bus Interface. The Power Management Controller allows the user to adjust the device activity according to system requirements, and, with the 32.768 kHz low-power oscillator, enables the AT91M42800 to reduce power requirements to an absolute minimum. The AT91M42800 is manufactured using Atmel’s high-density CMOS technology. By combining the ARM7TDMI processor core with on-chip SRAM and a wide range of peripheral functions including timers, serial communication controllers and a versatile clock generator on a monolithic chip, the AT91M42800 provides a highly flexible and cost-effective solution to many compute-intensive applications. Rev. 1328AS–06/00 1 Pin Configuration Figure 1. Pin Configuration in TQFP144 Package (Top View) 108 73 109 72 AT91M42800 33AI 144 37 1 36 Figure 2. Pin Configuration in BGA144 Package (Top View) 1 2 3 A B C D E F G H J K L M 2 AT91M42800 4 5 6 7 8 9 10 11 12 AT91M42800 Table 1. AT91M42800 Pinout in TQFP 144 Package Pin AT91M42800 Pin AT91M42800 Pin AT91M42800 Pin AT91M42800 1 GND 37 GND 73 GND 109 GND 2 GND 38 GND 74 GND 110 GND 3 NLB/A0 39 D4 75 PB22/TIOA5 111 PA26 4 A1 40 D5 76 PB23/TIOB5 112 GNDPLL 5 A2 41 D6 77 PA0/IRQ0 113 XIN 6 A3 42 D7 78 PA1/IRQ1 114 XOUT 7 A4 43 D8 79 PA2/IRQ2 115 GND 8 A5 44 D9 80 PA3/IRQ3 116 PLLRCA 9 A6 45 D10 81 PA4/FIQ 117 VDDPLL 10 A7 46 D11 82 PA5/SCK0 118 PLLRCB 11 A8 47 D12 83 PA6/TXD0 119 VDDPLL 12 VDDIO 48 VDDIO 84 VDDIO 120 VDDIO 13 GND 49 GND 85 GND 121 GND 14 A9 50 D13 86 PA7/RXD0 122 NWDOVF 15 A10 51 D14 87 PA8/SCK1 123 PA27/BMS 16 A11 52 D15 88 PA9/TXD1/NTRI 124 JTAGSEL 17 A12 53 PB6/TCLK0 89 PA10/RXD1 125 TMS 18 A13 54 PB7/TIOA0 90 PA11/SPCKA 126 TDI 19 A14 55 PB8/TIOB0 91 PA12/MISOA 127 TDO 20 A15 56 PB9/TCLK1 92 PA13/MOSIA 128 TCK 21 A16 57 PB10/TIOA1 93 PA14/NPCSA0/NSSA 129 NTRST 22 A17 58 PB11/TIOB1 94 PA15/NPCSA1 130 NRST 23 A18 59 PB12/TCLK2 95 PA16/NPCSA2 131 PA28/HOLDA 24 VDDIO 60 VDDIO 96 VDDIO 132 VDDIO 25 GND 61 GND 97 GND 133 GND 26 A19 62 PB13/TIOA2 98 PA17/NPCSA3 134 PA29/HOLD 27 PB2/A20/CS7 63 PB14/TIOB2 99 PA18/SPCKB 135 NWAIT 28 PB3/A21/CS6 64 PB15/TCLK3 100 PA19/MISOB 136 NOE/NRD 29 PB4/A22/CS5 65 PB16/TIOA3 101 PA20/MOSIB 137 NWE/NWR0 30 PB5/A23/CS4 66 PB17/TIOB3 102 PA21/NPCSB0/NSSB 138 NUB/NWR1 31 D0 67 PB18/TCLK4 103 PA22/NPCSB1 139 NCS0 32 D1 68 PB19/TIOA4 104 PA23/NPCSB2 140 NCS1 33 D2 69 PB20/TIOB4 105 PA24/NPCSB3 141 PB0/NCS2 34 D3 70 PB21/TCLK5 106 PA25/MCKO 142 PB1/NCS3 35 VDDCORE 71 VDDCORE 107 VDDCORE 143 VDDCORE 36 VDDIO 72 VDDIO 108 VDDIO 144 VDDIO 3 Table 2. AT91M42800 Pinout in BGA 144 Package 4 Pin AT91M42800 Pin AT91M42800 Pin AT91M42800 Pin AT91M42800 A1 PB1/NCS3 D1 A2 G1 A17 K1 D1 A2 NCS0 D2 A3 G2 A16 K2 VDDCORE A3 NCS1 D3 A4 G3 A11 K3 VDDIO A4 GND D4 NWAIT G4 A13 K4 D9 A5 PLLRCB D5 PA29/HOLD G5 GND K5 D10 A6 GND D6 PA28/HOLDA G6 GND K6 D14 A7 PLLRCA D7 TCK G7 GND K7 PB9/TCLK1 A8 GNDPLL D8 TMS G8 GND K8 PB13/TIOA2 A9 XOUT D9 JTAGSEL G9 PA9/TXD1/NTRI K9 PB11/TIOB1 A10 XIN D10 PA25/MCKO G10 PA10/RXD1 K10 VDDIO A11 GND D11 PA21/NPCSB0 G11 PA8/SCK1 K11 PB16/TIOA3 A12 PA22/NPCSB1 D12 PA18/SPCKB G12 PA7/RXD0 K12 PB23/TIOB5 B1 NUB/NWR1 E1 A7 H1 A18 L1 D3 B2 PB0/NCS2 E2 VDDIO H2 VDDIO L2 D2 B3 VDDCORE E3 A6 H3 A15 L3 D5 B4 NWE/NWR0 E4 A5 H4 A14 L4 D8 B5 VDDPLL E5 GND H5 A19 L5 VDDIO B6 TDO E6 GND H6 GND L6 D13 B7 VDDPLL E7 GND H7 GND L7 PB8/TIOB0 B8 NWDOVF E8 NTRST H8 GND L8 VDDIO B9 PA26 E9 PA13/MOSIA H9 PA6/TXD0 L9 PB17/TIOB3 B10 PA19/MISOB E10 PA16/NPCSA2 H10 PA4/FIQ L10 VDDCORE B11 PA24/NPCSB3 E11 VDDIO H11 VDDIO L11 PB20/TIOB4 B12 PA23/NPCSB2 E12 PA17/NPCSA3 H12 PA5/SCK0 L12 PB22/TIOA5 C1 NLB/A0 F1 A8 J1 PB5/A23/CS4 M1 D4 D6 C2 A1 F2 A12 J2 D0 M2 C3 VDDIO F3 A9 J3 PB4/A22/CS5 M3 D7 C4 NOE/NRD F4 A10 J4 PB3/A21/CS6 M4 D11 C5 VDDIO F5 GND J5 PB2/A20/CS7 M5 D12 C6 NRST F6 GND J6 D15 M6 PB7/TIOA0 C7 TDI F7 GND J7 PB6/TCLK0 M7 PB12/TCLK2 C8 VDDIO F8 GND J8 PB10/TIOA1 M8 PB15/TCLK3 C9 PA27/BMS F9 PA12/MISOA J9 PA3/IRQ3 M9 PB14/TIOB2 C10 VDDIO F10 PA15/NPCSA1 J10 PA2/IRQ2 M10 PB18/TCLK4 C11 VDDCORE F11 PA11/SPCKA J11 PA0/IRQ0 M11 PB19/TIOA4 C12 PA20/MOSIB F12 PA14/NPCSA0 J12 PA1/IRQ1 M12 PB21/TCLK5 AT91M42800 AT91M42800 Pin Description Table 3. AT91M42800 Pin Description Module EBI AIC TC USART SPIA SPIB PIO ST CLOCK Reset Name Function A0 - A23 Address Bus Type Active Level Output – D0 - D15 Data Bus I/O – CS4 - CS7 Chip Select Output High NCS0 - NCS3 Chip Select Output Low NWR0 Lower Byte 0 Write Signal Output Low Comments All valid after reset A23 - A20 after reset Used in Byte Write option NWR1 Lower Byte 1 Write Signal Output Low Used in Byte Write option NRD Read Signal Output Low Used in Byte Write option NWE Write Enable Output Low Used in Byte Select option NOE Output Enable Output Low Used in Byte Select option NUB Upper Byte Select (16-bit SRAM) Output Low Used in Byte Select option NLB Lower Byte Select (16-bit SRAM) Output Low Used in Byte Select option NWAIT Wait Input Input Low HOLD Bus Request from External Device Input High PIO-controlled after reset HOLDA Bus Grant to External Device Output High PIO-controlled after reset BMS Boot Mode Select Input – Sampled during reset IRQ0 - IRQ3 External Interrupt Request Input – PIO-controlled after reset FIQ Fast External Interrupt Request Input – PIO-controlled after reset TCLK0 - TCLK5 Timer External Clock Input – PIO-controlled after reset TIOA0 - TIOA5 Multi-purpose Timer I/O Pin A I/O – PIO-controlled after reset TIOB0 - TIOB5 Multi-purpose Timer I/O Pin B I/O – PIO-controlled after reset SCK0 - SCK1 External Serial Clock I/O – PIO-controlled after reset TXD0 - TXD1 Transmit Data Output Output – PIO-controlled after reset RXD0 - RXD1 Receive Data Input Input – PIO-controlled after reset SPCKA/SPCKB Clock I/O – PIO-controlled after reset MISOA/MISOB Master In Slave Out I/O – PIO-controlled after reset MOSIA/MOSIB Master Out Slave In I/O – PIO-controlled after reset NSSA/NSSB Slave Select Input Low PIO-controlled after reset NPCSA0 - NPCSA3 NPCSB0 - NPCSB3 Peripheral Chip Selects PA0 - PA29 Programmable I/O Port A I/O – Input after reset PB0 - PB23 Programmable I/O Port B I/O – Input after reset Output Low Input – Output – Input – NWDOVF Watchdog Timer Overflow XIN Oscillator Input XOUT Oscillator Output PLLRCA RC Filter for PLL A PLLRCB RC Filter for PLL B MCKO Clock Output NRST Hardware Reset Input Output Low Input – Output – Input Low PIO-controlled after reset Open drain Schmitt trigger 5 Table 3. AT91M42800 Pin Description (Continued) Module JTAG/ICE Emulation Power 6 Name Function Type Active Level Comments High enables IEEE 1149.1 JTAG boundary scan Low enables ARM Standard ICE debug Schmitt trigger JTAGSEL JTAG/ ICE selection Input TMS Test Mode Select Input – Schmitt trigger, internal pull-up TDI Test Data In Input – Schmitt trigger, internal pull-up Output – Input – TDO Test Data Out TCK Test Clock Schmitt trigger, internal pull-up NTRST Test Reset Input Input Low Schmitt trigger, internal pull-up NTRI Tri-state Mode Enable Input Low Sampled during reset VDDIO I/O Power Power – 3V or 5V nominal supply VDDCORE Core Power Power – 2V or 3V nominal supply VDDPLL PLL Power Power – 3V nominal supply GND Ground Ground – AT91M42800 AT91M42800 Block Diagram Figure 3. AT91M42800 NRST Reset Embedded ICE JTAG JTAGSEL JTAGSEL NTRST TMS TDO TDI TCK D0-D15 ARM7TDMI Core A0/NLB A1-A19 NRD/NOE NWR0/NWE NWR1/NUB NWAIT NCS0 NCS1 XIN XOUT Internal RAM 8K Bytes Clock Generator PLLRCA PLLRCB EBI: External Bus Interface ASB PA27/BMS PA28/HOLDA PA29HOLD ASB Controller PA25/MCKO PA26 PB0/NCS2 PB1/NCS3 PB2/A20/CS7 PB3/A21/CS6 PB4/A22/CS5 PB5/A23/CS4 AMBA™ Bridge PA0/IRQ0 PA1/IRQ1 PA2/IRQ2 PA3/IRQ3 PA4/FIQ AIC: Advanced Interrupt Controller PA5/SCK0 PA6/TXD0 PA7/RXD0 PA8/SCK1 PA9/TXD1/NTRI PA10/RXD1 PA11/SPCKA PA12/MISOA PA13/MOSIA PA14/NPCSA0/NSSA PA15/NPCSA1 PA16/NPCSA2 PA17/NPCSA3 PA18/SPCKB PA19/MISOB PA20/MOSIB PA21/NPCSB0/NSSB PA22/NPCSB1 PA23/NPCSB2 PA24/NPCSB3 EBI User Interface USART0 2 PDC Channels USART1 2 PDC Channels TC: Timer/ Counter Block 0 APB P I O SPIB: Serial Peripheral Interface 2 PDC Channels 2 PDC Channels PB7/TIOA0 PB8/TIOB0 TC0 TC1 TC2 SPIA: Serial Peripheral Interface PB6/TCLK0 PB9/TCLK1 PB12/TCLK2 P I O PB10/TIOA1 PB11/TIOB1 PB13/TIOA2 PB14/TIOB2 TC: Timer/ Counter Block 1 PB15/TCLK3 PB18/TCLK4 PB21/TCLK5 TC3 PB16/TIOA3 PB17/TIOB3 TC4 PB19/TIOA4 PB20/TIOB4 TC5 PB22/TIOA5 PB23/TIOB5 System Timers PMC: Power Management Controller Watchdog NWDOVF Real-time Period Interval Chip ID PIO: Parallel I/O Controller 7 Architectural Overview The AT91M42800 Microcontroller integrates an ARM7TDMI with its embedded ICE interface, memories and peripherals. Its architecture consists of two main buses, the Advanced System Bus (ASB) and the Advanced Peripheral Bus (APB). Designed for maximum performance and controlled by the memory controller, the ASB interfaces the ARM7TDMI processor with the on-chip 32-bit memories, the External Bus Interface (EBI) and the AMBA™ Bridge. The AMBA Bridge drives the APB, which is designed for accesses to on-chip peripherals and optimized for low power consumption. The AT91M42800 Microcontroller implements the ICE port of the ARM7TDMI processor on dedicated pins, offering a complete, low-cost and easy-to-use debug solution for target debugging. Memories The AT91M42800 Microcontroller embeds up to 8K bytes of internal SRAM. The internal memory is directly connected to the 32-bit data bus and is single-cycle accessible. This provides maximum performance of 30 MIPS at 33 MHz by using the ARM instruction set of the processor. The on-chip memory significantly reduces the system power consumption and improves its performance over external memory solutions. The AT91M42800 Microcontroller features an External Bus Interface (EBI), which enables connection of external memories and application-specific peripherals. The EBI supports 8- or 16-bit devices and can use two 8-bit devices to emulate a single 16-bit device. The EBI implements the early read protocol, enabling faster memory accesses than standard memory interfaces. Peripherals The AT91M42800 Microcontroller integrates several peripherals, which are classified as system or user peripherals. All on-chip peripherals are 32-bit accessible by the AMBA Bridge, and can be programmed with a minimum number of instructions. The peripheral register set is composed of control, mode, data, status and enable/disable/status registers. An on-chip Peripheral Data Controller (PDC) transfers data between the on-chip USARTs/SPIs and the on- and offchip memories without processor intervention. Most importantly, the PDC removes the processor interrupt handling overhead and significantly reduces the number of clock cycles required for a data transfer. It can transfer up to 64K continuous bytes without reprogramming the start address. As a result, the performance of the microcontroller is increased and the power consumption reduced. 8 AT91M42800 System Peripherals The External Bus Interface (EBI) controls the external memory and peripheral devices via an 8- or 16-bit data bus and is programmed through the APB. Each chip select line has its own programming register. The Power Management Controller (PMC) optimizes power consumption of the product by controlling the clocking elements such as the oscillators and the PLL, system and user peripheral clocks. The Advanced Interrupt Controller (AIC) controls the internal sources from the internal peripherals and the five external interrupt lines (including the FIQ) to provide an interrupt and/or fast interrupt request to the ARM7TDMI. It integrates an 8-level priority controller, and, using the Autovectoring feature, reduces the interrupt latency time. The Parallel Input/Output Controllers (PIOA, PIOB) controls up to 54 I/O lines. It enables the user to select specific pins for on-chip peripheral input/output functions, and general-purpose input/output signal pins. The PIO controllers can be programmed to detect an interrupt on a signal change from each line. There are three embedded system timers. The Real-time Timer (RTT) counts elapsed seconds and can generate periodic or programmed interrupts. The Period Interval Timer (PIT) can be used as a user-programmable timebase, and can generate periodic ticks. The Watchdog (WD) can be used to prevent system lock-up if the software becomes trapped in a deadlock. The Special Function (SF) module integrates the Chip ID and the Reset Status registers. User Peripherals Two USARTs, independently configurable, enable communication at a high baud rate in synchronous or asynchronous mode. The format includes start, stop and parity bits and up to 9 data bits. Each USART also features a Time-out and a Time-guard register, facilitating the use of the two dedicated Peripheral Data Controller (PDC) channels. The two 3-channel, 16-bit Timer/Counters (TC) are highlyprogrammable and support capture or waveform modes. Each TC channel can be programmed to measure or generate different kinds of waves, and can detect and control two input/output signals. Each TC also has three external clock signals. Two independently configurable SPIs provide communication with external devices in master or slave mode. Each has four external chip selects which can be connected to up to 15 devices. The data length is programmable, from 8to 16-bit. AT91M42800 Supervisor Mode Protection The following system peripherals are protected against unintentional accesses by the Supervisor Operating Mode. • External Bus Interface (EBI) • Power Management Controller (PMC) • System Timers (ST) • Special Function (SF) 9 Associated Documentation Information Document Title Internal architecture of processor ARM/Thumb instruction sets Embedded in-circuit emulator ARM7TDMI (Thumb) Datasheet Mapping Peripheral operation Peripheral user interface AT91M42800 Datasheet Timings DC characteristics AT91M42800 Electrical Characteristics Datasheet 10 AT91M42800 AT91M42800 Product Overview Power Supply Reset The AT91M42800 has three kinds of power supply pins: • VDDCORE pins, which power the chip core Reset initializes the user interface registers to their default states as defined in the peripheral sections of this datasheet and forces the ARM7TDMI to perform the next instruction fetch from address zero. Except for the program counter the ARM core registers do not have defined reset states. When reset is active, the inputs of the AT91M42800 must be held at valid logic levels. The EBI address lines drive low during reset. All the peripheral clocks are disabled during reset to save power. • VDDIO pins, which power the I/O lines • VDDPLL pins, which power the oscillator and PLL cells VDDCORE and VDDIO allow core power consumption to be reduced by supplying it with a lower voltage than the I/O lines. The VDDCORE pins must never be powered at a voltage greater than the supply voltage applied to the VDDIO. The VDDPLL pin is used to supply the oscillator and both PLLs. The voltage applied on these pins is typically 3.3V, and it must not be lower than VDDCORE. Typical supported voltage combinations are shown in the following table: Pins Nominal Supply Voltages VDDCORE 3.3V 3.0V or 3.3V 2.0V VDDIO 5.0V 3.0V or 3.3V 3.3V VDDPLL 3.3V 3.0V or 3.3V 3.3V Max Freq 33 MHz 33 MHz 17 MHz Input/Output Considerations After the reset, the peripheral I/Os are initialized as inputs to provide the user with maximum flexibility. It is recommended that in any application phase, the inputs to the AT91M42800 Microcontroller be held at valid logic levels to minimize the power consumption. NRST Pin NRST is the active low reset input. It is asserted asynchronously, but exit from reset is synchronized internally to the slow clock (SLCK). At power-up, NRST must be active until the on-chip oscillator is stable. During normal operation, NRST must be active for a minimum of 10 oscillator clock cycles to ensure correct initialization. The pins BMS and NTRI are sampled during the 10 clock cycles just prior to the rising edge of NRST. The NRST pin has no effect on the on-chip Embedded ICE logic. Watchdog Reset The internally generated watchdog reset has the same effect as the NRST pin, except that the pins BMS and NTRI are not sampled. Boot mode and Tri-state Mode are not updated. The NRST pin has priority if both types of reset coincide. Emulation Functions Clock Generator Tri-state Mode The AT91M42800 Microcontroller embeds a 32.768 kHz oscillator that generates the Slow Clock (SLCK). The AT91M42800 provides a Tri-state Mode, which is used for debug purposes in order to connect an emulator probe to an application board. In Tri-state Mode the AT91M42800 continues to function, but all the output pin drivers are tristated. The AT91M42800 Microcontroller has a fully static design and works either on the Master Clock (MCK), generated from the Slow Clock by means of the two integrated PLLs, or on the Slow Clock (SLCK). These clocks are also provided as an output of the device on the pin MCKO, which is multiplexed with a general-purpose I/O line. While NRST is active, and after the reset, the MCKO is valid and outputs an image of the SLCK signal. The PIO Controller must be programmed to use this pin as standard I/O line. To enter Tri-state Mode, the pin NTRI must be held low during the last 10 clock cycles before the rising edge of NRST. For normal operation, the pin NTRI must be held high during reset, by a resistor of up to 400K Ohm. NTRI must be driven to a valid logic value during reset. NTRI is multiplexed with Parallel I/O PA9 and USART 1 serial data transmit line TXD1. Standard RS232 drivers generally contain internal 400K Ohm pull-up resistors. If TXD1 is connected to one of these drivers this pull-up will ensure normal operation, without the need for an additional external resistor. 11 Embedded ICE ARM standard embedded In-circuit Emulation is supported via the JTAG/ICE port. It is connected to a host computer via an Embedded ICE Interface. Embedded ICE mode is selected when JTAGSEL is low. It is not possible to switch directly between ICE and JTAG operations. A chip reset must be performed (NRST and NTRST) after JTAGSEL is changed. The reset input to the Embedded ICE (NTRST) is provided separately to facilitate debug of boot programs. IEEE 1149.1 JTAG Boundary Scan IEEE 1149.1 JTAG Boundary Scan is enabled when JTAGSEL is high. The functions SAMPLE, EXTEST and BYPASS are implemented. In ICE Debug mode the ARM core responds with a nonJTAG chip ID that identifies the core to the ICE system. This is not IEEE 1149.1 JTAG compliant. It is not possible to switch directly between JTAG and ICE operations. A chip reset must be performed (NRST and NTRST) after JTAGSEL is changed. Memory Controller The ARM7TDMI processor address space is 4G bytes. The memory controller decodes the internal 32-bit address bus and defines three address spaces: • Internal Memories in the four lowest megabytes • Middle Space reserved for the external devices (memory or peripherals) controlled by the EBI • Internal Peripherals in the four highest megabytes In any of these address spaces, the ARM7TDMI operates in Little-Endian mode only. The input level on the BMS pin during the last 10 clock cycles before the rising edge of the NRST selects the type of boot memory. The Boot mode depends on BMS (see Table 4). The pin BMS is multiplexed with the I/O line PA27 that can be programmed after reset like any standard PIO line. Table 4. Boot Mode Select BMS Boot Memory 1 External 8-bit memory NCS0 0 External 16-bit memory on NCS0 Remap Command The ARM vectors (Reset, Abort, Data Abort, Prefetch Abort, Undefined Instruction, Interrupt, Fast Interrupt) are mapped from address 0x0 to address 0x20. In order to allow these vectors to be redefined dynamically by the software, the AT91M42800 Microcontroller uses a remap command that enables switching between the boot memory and the internal RAM bank addresses. The remap command is accessible through the EBI User Interface, by writing one in RCB of EBI_RCR (Remap Control Register). Performing a remap command is mandatory if access to the other external devices (connected to chip selects 1 to 7) is required. The remap operation can only be changed back by an internal reset or an NRST assertion. Abort Control The abort signal providing a Data Abort or a Prefetch Abort exception to the ARM7TDMI is asserted in the following cases: • When accessing an undefined address in the EBI address space, or writing to a write-protected bank • When the ARM7TDMI performs a misaligned access Internal Memories The AT91M42800 Microcontroller integrates internal SRAM. All internal memories are 32 bits wide and singleclock cycle accessible. The AT91M42800 Microcontroller integrates a primary 8Kbyte SRAM bank that is mapped at address 0x0 (after the remap command), and ARM7TDMI exception vectors between 0x0 and 0x20 that can be modified by the software. The rest of the bank can be used for stack allocation (to speed up context saving and restoring), or as data and program storage for critical algorithms. Boot Mode Select The ARM reset vector is at address 0x0. After the NRST line is released, the ARM7TDMI executes the instruction stored at this address. This means that this address must be mapped in nonvolatile memory after the reset. 12 AT91M42800 No abort is generated when reading the internal memory or by accessing the internal peripherals, whether the address is defined or not. When a write-protected area is accessed, the memory controller detects it, generates an abort and cancels the access. When the processor performs a forbidden write access in a mode-protected peripheral register, the write is cancelled but no abort is generated. The processor can perform word or half-word data access with a misaligned address when a register relative load/store instruction is executed and the register contains a misaligned address. In this case, whether the access is in write or in read, an abort is generated but the access is not cancelled. The Abort Status Register traces the source that caused the last abort. The address and the type of abort are stored in registers of the External Bus Interface. AT91M42800 External Bus Interface The External Bus Interface handles the accesses between addresses 0x0040 0000 and 0xFFC0 0000. It generates the signals that control access to the external devices, and can be configured from eight 1-Mbyte banks up to four 16Mbyte banks. In all cases it supports byte, half-word and word aligned accesses. For each of these banks, the user can program: • Number of wait states • Number of data float times (wait time after the access is finished to prevent any bus contention in case the device is too long in releasing the bus) • Data bus width (8-bit or 16-bit) • With a 16-bit wide data bus, the user can program the EBI to control one 16-bit device (Byte Access Select mode) or two 8-bit devices in parallel that emulate a 16-bit memory (Byte Write Access mode). The External Bus Interface features also the Early Read Protocol, configurable for all the devices, that significantly reduces access time requirements on an external device. Peripherals The AT91M42800 peripherals are connected to the 32-bit wide Advanced Peripheral Bus. Peripheral registers are only word accessible. Byte and half-word accesses are not supported. If a byte or a half-word access is attempted, the memory controller automatically masks the lowest address bits and generates a word access. Each peripheral has a 16-Kbyte address space allocated (the AIC only has a 4-Kbyte address space). Peripheral Registers The following registers are common to all peripherals: • Control Register – Write-only register that triggers a command when a one is written to the corresponding position at the appropriate address. Writing a zero has no effect. • Mode Register – read/write register that defines the configuration of the peripheral. Usually has a value of 0x0 after a reset. • Data Registers – read and/or write register that enables the exchange of data between the processor and the peripheral. • Status Register – Read-only register that returns the status of the peripheral. • Enable/Disable/Status Registers – shadow command registers. Writing a one in the Enable Register sets the corresponding bit in the Status Register. Writing a one in the Disable Register resets the corresponding bit and the result can be read in the Status Register. Writing a bit to zero has no effect. This register access method maximizes the efficiency of bit manipulation, and enables modification of a register with a single non-interruptible instruction, replacing the costly read-modify-write operation. Unused bits in the peripheral registers are shown as “–” and must be written at 0 for upward compatibility. These bits read 0. Peripheral Interrupt Control The Interrupt Control of each peripheral is controlled from the status register using the interrupt mask. The status register bits are ANDed to their corresponding interrupt mask bits and the result is then ORed to generate the Interrupt Source signal to the Advanced Interrupt Controller. The interrupt mask is read in the Interrupt Mask Register and is modified with the Interrupt Enable Register and the Interrupt Disable Register. The enable/disable/status (or mask) makes it possible to enable or disable peripheral interrupt sources with a non-interruptible single instruction. This eliminates the need for interrupt masking at the AIC or Core level in real-time and multi-tasking systems. Peripheral Data Controller The AT91M42800 has an 8-channel PDC dedicated to the two on-chip USARTs and to the two on-chip SPIs. One PDC channel is connected to the receiving channel and one to the transmitting channel of each peripheral. The user interface of a PDC channel is integrated in the memory space of each USART channel and in the memory space of each SPI. It contains a 32-bit address pointer register and a 16-bit count register. When the programmed data is transferred, an end-of-transfer interrupt is generated by the corresponding peripheral. See the USART section and the SPI section for more details on PDC operation and programming. 13 System Peripherals PMC: Power Management Controller The AT91M42800 Power Management Controller optimizes the power consumption of the device. The PMC controls the clocking elements such as the oscillator and the PLLs, and the System and the Peripheral Clocks. It also controls the MCKO pin and permits to the user to select four different signals to be driven on this pin. The AT91M42800 has the following clock elements: • The oscillator providing a clock that depends on the crystal fundamental frequency connected between the XIN and XOUT pins • PLL A providing a low to middle frequency clock range • PLL B providing a middle to high frequency range • The Clock prescaler • The ARM Processor Clock Controller AIC: Advanced Interrupt Controller The AT91M42800 has an 8-level priority, individually maskable, vectored interrupt controller. This feature substantially reduces the software and real-time overhead in handling internal and external interrupts. The interrupt controller is connected to the NFIQ (fast interrupt request) and the NIRQ (standard interrupt request) inputs of the ARM7TDMI processor. The processor’s NFIQ line can only be asserted by the external fast interrupt request input: FIQ. The NIRQ line can be asserted by the interrupts generated by the on-chip peripherals and the external interrupt request lines: IRQ0 to IRQ3. The 8-level priority encoder allows the customer to define the priority between the different NIRQ interrupt sources. Internal sources are programmed to be level sensitive or edge triggered. External sources can be programmed to be positive or negative edge triggered or high or low level sensitive. • The Peripheral Clock Controller • The Master Clock Output Controller PIO: Parallel I/O Controller The on-chip low-power oscillator together with the PLLbased frequency multiplier and the prescaler results in a programmable clock between 500 Hz and 66 MHz. It is the responsibility of the user to make sure that the PMC programming does not result in a clock over the acceptable limits. The AT91M42800 has 54 programmable I/O lines. I/O lines are multiplexed with an external signal of a peripheral to optimize the use of available package pins. These lines are controlled by two separate and identical PIO Controllers called PIOA and PIOB. Each PIO controller also provides an internal interrupt signal to the Advanced Interrupt Controller and insertion of a simple input glitch filter on any of the PIO pins. ST: System Timer The System Timer module integrates three different freerunning timers: • A Period Interval Timer setting the base time for an Operating System • A Watchdog Timer that is built around a 16-bit counter, and is used to prevent system lock-up if the software becomes trapped in a deadlock. It can generate an internal reset or interrupt, or assert an active level on the dedicated pin NWDOVF. • A Real-Time Timer counting elapsed seconds These timers count forwards or backwards using a Slow Clock provided by the MCU. Typically, this clock has a frequency of 32768 kHz. 14 AT91M42800 SF: Special Function The AT91M42800 provides registers that implement the following special functions. • Chip Identification • RESET Status AT91M42800 User Peripherals USART: Universal Synchronous/Asynchronous Receiver Transmitter The AT91M42800 provides two identical, full-duplex, universal synchronous/asynchronous receiver/transmitters that interface to the APB and are connected to the Peripheral Data Controller. The main features are: • Programmable Baud Rate Generator with External or Internal Clock, as well as Slow Clock • Parity, Framing and Overrun Error Detection • Line Break Generation and Detection • Automatic Echo, Local Loopback and Remote Loopback channel modes • Multi-drop mode: Address Detection and Generation • Interrupt Generation • Two Dedicated Peripheral Data Controller channels • 5-, 6-, 7-, 8- and 9-bit character length TC: Timer/Counter The AT91M42800 features two Timer/Counter blocks, each containing three identical 16-bit Timer/Counter channels. Each channel can be independently programmed to per- form a wide range of functions including frequency measurement, event counting, interval measurement, pulse generation, delay timing and pulse-width modulation. Each Timer/Counter channel has 3 external clock inputs, 5 internal clock inputs, and 2 multi-purpose input/output signals that can be configured by the user. Each channel drives an internal interrupt signal that can be programmed to generate processor interrupts via the AIC (Advanced Interrupt Controller). The Timer/Counter block has two global registers that act upon all three TC channels. The Block Control Register allows the three channels to be started simultaneously with the same instruction. The Block Mode Register defines the external clock inputs for each Timer/Counter channel, allowing them to be chained. Each Timer/Counter block operates independently and has a complete set of block and channel registers. SPI: Serial Peripheral Interface The AT91M42800 includes two SPIs that provide communication with external devices in master or slave mode. They are independent, and are referred to by the letters A and B. Each SPI has four external chip selects that can be connected to up to 15 devices. The data length is programmable from 8- to 16-bit. 15 Ordering Information Max Speed (MHz) Core Operating Power Supply Range Ordering Code 33 2.7V to 3.6V AT91M42800-33CI 33 2.7V to 3.6V AT91M42800-33AI 16 AT91M42800 RAM (Bytes) 8K Package BGA 144 TQFP 144 Operating Temperature Range -40°C to 85°C AT91M42800 Package Outline 144-lead TQFP Table 5. Common Dimensions (mm) Symbol Min Nom Max c 0.09 0.2 c1 0.09 0.16 L 0.45 0.6 L1 0.75 1.00 REF R2 0.08 R1 0.08 S 0.2 q 0° q1 0° q2 q3 0.2 3.5° 7° 11° 12° 13° 11° 12° 13° A 1.6 A1 0.05 A2 1.35 0.15 1.4 1.45 Tolerances and form of position aaa 0.2 bbb 0.2 Table 6. Lead Count Dimensions b b1 Pin Count D/E BSC D1/E1 BSC Min Nom Max Min Nom Max e BSC ccc ddd 144 22.0 2.0 0.17 0.22 0.27 0.17 0.2 0.23 0.50 0.10 0.08 17 Figure 4. 144-lead TQFP Package Drawing θ2 θ1 θ3 θ 18 AT91M42800 AT91M42800 Package Outline 144-ball BGA Figure 5. 144-ball BGA Package Drawing TOP VIEW BOTTOM VIEW Symbol Max. SIDE VIEW 19 Atmel Headquarters Atmel Operations Corporate Headquarters Atmel Colorado Springs 2325 Orchard Parkway San Jose, CA 95131 TEL (408) 441-0311 FAX (408) 487-2600 Europe Atmel U.K., Ltd. Coliseum Business Centre Riverside Way Camberley, Surrey GU15 3YL England TEL (44) 1276-686-677 FAX (44) 1276-686-697 1150 E. Cheyenne Mtn. Blvd. Colorado Springs, CO 80906 TEL (719) 576-3300 FAX (719) 540-1759 Atmel Rousset Zone Industrielle 13106 Rousset Cedex France TEL (33) 4-4253-6000 FAX (33) 4-4253-6001 Asia Atmel Asia, Ltd. Room 1219 Chinachem Golden Plaza 77 Mody Road Tsimhatsui East Kowloon Hong Kong TEL (852) 2721-9778 FAX (852) 2722-1369 Japan Atmel Japan K.K. 9F, Tonetsu Shinkawa Bldg. 1-24-8 Shinkawa Chuo-ku, Tokyo 104-0033 Japan TEL (81) 3-3523-3551 FAX (81) 3-3523-7581 Fax-on-Demand North America: 1-(800) 292-8635 International: 1-(408) 441-0732 e-mail [email protected] Web Site http://www.atmel.com BBS 1-(408) 436-4309 © Atmel Corporation 2000. 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