![]() ![]() All I/O locations may be accessed by the LD/LDS/LDD and ST/STS/STD instructions, transferring data between the 32 general purpose working registers and the I/O space. ATmega328P Input/Output (I/O) MemoryĪTmega328P I/Os and peripherals are placed in the I/O space. These issues are the same as for board level systems using EEPROM, and the same design solutions should be applied. When the EEPROM is written, the CPU is halted for two clock cycles before the next instruction is executed.ĭuring periods of low VCC, the EEPROM data can be corrupted because the supply voltage is too low for the CPU and the EEPROM to operate properly. The EEPROM read access takes one instruction, and the requested data is available immediately. When the EEPROM is read, the CPU is halted for four clock cycles before the next instruction is executed. 1.8ms to Erase Only and 1.8ms to Write Only. An EEPROM write takes 3.4ms to Erase and Write in one operation (Atomic Operation). In order to prevent unintentional EEPROM writes, a specific write procedure must be followed to reduce wear. The EEPROM Access Registers are accessible in the I/O space. The access between the EEPROM and the CPU is performed using the EEPROM Address Registers, the EEPROM Data Register, and the EEPROM Control Register. The EEPROM has an endurance of at least 100,000 writes/erase cycles. It is organized as a separate data space, in which single bytes can be read and written. The ATmega328P contains 1Kbytes of data EEPROM memory. The internal data SRAM access takes two clk CPU cycles.ĪTmega328P RAM Access Timing Diagram ATmega328P EEPROM Data Memory Indirect with Post-increment – The address registers X, Y, and Z are incremented.Indirect with Pre-decrement – The address registers X, Y, and Z are decremented.Indirect with Displacement – The Indirect with Displacement mode reaches 63 address locations from the base address given by the Y or Z register.Indirect – In the Register File, registers R26 to R31 feature the indirect addressing pointer registers.Direct – The direct addressing reaches the entire data space.There are five different data bus addressing modes for the data memory: SRAM is used for temporarily storing intermediate results and variables, stack within a software application. Some AVR microcontrollers with more peripherals need more space than the I/O memory can address so some of the SRAM is used as Extended I/O memory to handle the extra peripherals control registers and other I/O functions I/O Memory (64 x 8-bit) (0020 16–005F 16)Ĭontains addressable space for peripheral control registers and other I/O registers.Registers (32 x 8-bit) (0000 16–001F 16)Ĭonsists of 32 8-bit general purpose working registers (R0-R31).The ATmega328P Data Memory Address Space consists of The lower 2303 data memory locations address consists of the first 32 locations address the Register File, the next 64 location the standard I/O memory, then 160 locations of Extended I/O memory, and the next 2048 locations address the internal data SRAM. This memory can also be accessed by the standard data bus using a 0x20 address offset in the access command. The IN/OUT data bus has direct access to the 64-byte I/O Memory section (not Extended) using a 0x00 to 0x1F address. For the Extended I/O space from 0圆0 – 0xFF in SRAM, only the ST/STS/STD (Store) and LD/LDS/LDD (Load) instructions can be used. The ATmega328P is a complex microcontroller with more peripheral units than can be supported within the 64 locations reserved in the Opcode for the IN and OUT instructions. These support endless possible applications for this small and affordable package. A wide range of flexible I/O options includes I2C, SPI, and uniquely Programmable I/O (PIO). Raspberry Pi Pico RP2040 Designed by Raspberry Pi, RP2040 features a dual-core Arm Cortex-M0+ processor with 264KB internal RAM and support for up to 16MB of off-chip Flash.Atmel The popular, tiny and low-cost 8-bit AVR microcontrollers from Atmel.Arduino Tutorial – The Industrial and Professional Way.Line Follower Robot Development Documentation for Line Follower Robot.Online Courses Online Courses on various topics and technologies.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |