Moderator: nferre. Users browsing this forum: Majestic [Bot] and 2 guests. Posts: 87 Joined: , The main thing that I am confused about is what pins I need to worry about to get the chip into the system recovery procedure.
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A complete set of system functions minimizes the number of external components Figure The internal regulator input con- nected to the 3. The TST pin integrates a permanent pull-down resis- tor of about GND, so that it can be left unconnected for normal operations At any time, the ROM is mapped at address 0x30 Embedded Flash 9.
It reads as 65, bit words. It reads as 32, bit words. The Flash contains a byte write buffer, accessible through a bit interface. When the secu- rity is enabled, any access to the Flash, either through the ICE interface or through the Fast Flash Programming Interface, is forbidden.
This ensures the confidentiality of the code pro- grammed in the Flash. System Controller The System Controller manages all vital blocks of the microcontroller: interrupts, clocks, power, time, debug and reset. Both signals are provided to the Flash to prevent any code corruption during power-up or power- down sequences or if brownouts occur on the power supplies. Peripherals Each PIO Controller controls 31 lines.
Each line can be assigned to one of two peripheral func- tions Some of them can also be multiplexed with the analog inputs of the ADC Controller Unique peripheral identifiers are defined for both the Advanced Interrupt Controller and the Power Management Controller. Table Peripheral Programmable delay between consecutive transfers — Selectable mode fault detection — Maximum frequency Master Clock Receiver and transmitter include a data signal, a clock signal and a frame synchronization signal At any one time 16 registers are visible to the user.
The remainder are synonyms used to speed up exception processing. Register 15 is the Program Counter PC and can be used in all instructions to reference data relative to the current instruction. R14 holds the return address after a subroutine call. R13 is used by software convention stack pointer. R13 is banked across exception modes to provide each exception handler with a private stack pointer.
The fast interrupt mode also banks registers that interrupt processing can begin with- out having to save these registers. Every instruction contains a 4-bit condition code field bit. In Thumb mode, eight general-purpose registers R7, are available that are the same physical registers when executing ARM instructions. Application Examples A specific register, the Debug Unit Chip ID Register, gives information about the product version and its internal configuration. For further details on the Debug Unit, see the Debug Unit section.
Set to 0x0. Set to 0x1. The Reset Controller also drives independently or simultaneously the external reset and the peripheral and processor resets. A brownout detection is also available to prevent the processor from falling into an unpredictable state.
At factory, the brownout reset is disabled. Brownout Reset. If KEY is correct, resets the peripherals. Writing any other value in this field aborts the write operation.
The reset controller is ready for a software command software reset command is being performed by the reset controller. The reset controller is busy.
This field defines the external reset length. To prevent several executions of the interrupt handler, the interrupt must be disabled in the interrupt handler and re-enabled when the status register is clear. This also resets the bit counter. Block Diagram Figure PIT counting. The PIT is stopped when the core enters debug state. Mode Register. Its offset is 0x60 with respect to the System Controller offset.
This register controls the Voltage Regulator Mode. Embedded Flash Controller. This allows easy debug of the user-defined boot sequence by offering a simple way to put the chip in the same configuration as after a reset. Note that the accesses of the ARM processor when it is fetching instructions are not checked. The misalignments are generally due to software bugs leading to wrong pointer handling. These bugs are particularly difficult to detect in the debug phase.
As the requested address is saved in the Abort Status Register and the address of the instruc- tion generating the misalignment is saved in the Abort Link Register of the processor, detection and fix of this kind of software bugs is simplified. GP NVM assignment. The Embedded Flash size, the page size and the lock region organization are described in the product definition section.
The Flash memory is accessible through 8-, and bit reads. As the Flash block size is smaller than the address space reserved for the internal memory area, the embedded Flash wraps around the address space and appears to be repeated within it. Flash erasing. The Flash technology requires that an erase must be done before programming. A command must be previously run to unlock the corresponding region. ERASE request to the chip. When writing the rest of the Flash, this field defines the number of Master Clock cycles in 1.
This number must be rounded up. Warning: The value 0 is only allowed for a master clock period superior to 30 microseconds. If the field is writ- ten with a different value, the write is not performed and no action is started. Parallel Fast Flash Programming Only a certain set of pins is significant. Other pins must be left unconnected. An handshake is defined for read and write operations.
When a new command is executed, the previous one is automatically achieved. Thus, chaining a read command after a write automatically flushes the load buffer in the Flash. Write handshaking can be chained; an internal address buffer is automatically increased. When bit 0 of the bit mask is set, then the first lock bit is activated. All the lock bits are also cleared by the EA command. The n NVM bit is active when bit n of the bit mask is set..
This command is used to perform a write access to any memory location. This input can be tied to GND. Note: Table Debug Comms Registers. The memory map is accessible through this command. Memory is seen as an array of words bit wide. How- ever, before programming the load buffer, the page is erased. An internal address buffer is automatically increased. Disable of the Watchdog and enable of the user reset AutoBaudrate Flow Diagram Table Yes No Character '0x80' received?
Yes No Character ' ' received? The device handles standard requests as defined in the USB Specification. The peripheral triggers PDC transfers using transmit and receive signals. When the pro- grammed data is transferred, an end of transfer interrupt is generated by the corresponding peripheral. When the counter reaches zero, the transfer is complete and the PDC stops transfer- ring data.
If the Next Counter Register is equal to zero, the PDC disables the trigger while activating the related peripheral end flag. If simultaneous requests of the same type receiver or transmitter occur on identical peripher- als, the priority is determined by the numbering of the peripherals. If transfer requests are not simultaneous, they are treated in the order they occurred.
AT91SAM7X256 PDF Datasheet浏览和下载
AT91SAM7X256-AU-001 ATMEL Corporation, AT91SAM7X256-AU-001 Datasheet