NXP Flash MCU to Atmel Flash MCU Cross Reference. 07/01/ 86KB. NXP Flash MCU to Atmel Flash MCU Devices, Non-Direct Replacements. 07/01/ The device is manufactured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and. 89C55 datasheet, 89C55 circuit, 89C55 data sheet: ATMEL – 8-Bit Microcontroller with 20K Bytes Flash,alldatasheet, datasheet, Datasheet search site for.
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In this application, Port 2 uses strong internal pul- lups when emitting 1s.
89C55 Datasheet(PDF) – ATMEL Corporation
Note that stack operations are examples of indirect addressing, so the upper bytes of data RAM are avail- able as stack space. Otherwise, the pin is weakly pulled high. As inputs, Port 3 pins that are externally being pulled low will source current I. Three-Level Program Memory Lock. When 1s are written to Port 2 pins, they are pulled high by the internal pullups atmle can be used as inputs.
Port 0 also receives the code bytes during Flash program- ming and outputs the code bytes during program verifica- tion. Port 2 emits the high-order address byte during fetches from external program memory and during accesses to external data memory that use bit addresses MOVX DPTR.
In addition, the AT89C55 is designed with static logic for operation down to zero frequency and sup- ports two software selectable power saving modes.
XTAL2 Output from the inverting oscillator amplifier. User software should not write 1s to these unlisted loca- tions, since atel may be used in future products to invoke new features.
T1 timer 1 external input. As inputs, Port 2 pins that are externally being pulled low will source current I. INT1 external interrupt 1.
External pullups are required during program verifica- tion. The upper bytes occupy a parallel address space to the Special Function Registers. Port 3 also serves the functions 8955 various special features of the AT89C55, as shown in the following table.
Note that not all of the addresses are occupied, and unoc- cupied addresses may not be implemented on the chip. RXD serial input port. Note, however, that one ALE pulse is skipped during each access to external data mem- ory. Setting the ALE-disable bit has no effect if the microcontroller is in external execution mode.
Read accesses to these addresses will in general return random data, and write accesses will have an indetermi- nate effect. When 1s are written attmel Port 3 pins, they are pulled high by the internal pullups and can be used as inputs.
The low-voltage option saves power and operates with a 2.
WR external data memory write strobe. As inputs, Port 1 pins that are externally being pulled low will source current I. When 1s are written to Port 1 pins, they are pulled high by the internal pullups and can be used as inputs.
Instructions that use direct addressing access SFR space. Port 2 also receives the high-order address bits and some control signals during Flash programming and verification. RD external data memory read strobe. Two priorities can be set for each of the six interrupt sources in the IP register.
A high on this pin for two machine cycles while the oscillator is running resets the device. For example, the following indirect addressing instruction, where R0 contains 0A0H, accesses the data byte at address 0A0H, rather than P2 whose address is 0A0H. INT0 external interrupt 0. The on-chip Flash allows the program memory to be reprogrammed in-system or by a conventional nonvolatile memory programmer.
T0 timer 0 external input. Interrupt Registers The individual interrupt enable bits are in the IE register. The device is manu- factured using Atmel’s high density nonvolatile memory technology and is compatible with the industry standard 80C51 instruction set and pinout. By combining a versatile 8-bit CPU with Flash on a monolithic chip, the Atmel AT89C55 is a powerful microcomputer which provides a highly flexible and cost effective solution to many embedded control applications.
Instructions that use indirect addressing access the upper bytes of RAM. Search field Part name Part description. In this mode, P0 has internal pul- lups. XTAL1 Input to the inverting oscillator amplifier and input to the internal clock operating circuit.
Port 3 also receives the highest-order address bit and some control signals for Flash programming and verifica- tion. TXD serial output port. When 1s are written to port 0 pins, the pins can be used as high- impedance inputs. The AT89C55 provides the following standard features: This pin also receives the volt programming enable volt- age V. As an output port, each pin can sink eight TTL inputs.
Note, however, that if lock bit 1 is programmed, EA will be internally latched on reset.
89C55 Datasheet pdf – 8-Bit Microcontroller with 20K Bytes Flash – Atmel
In that case, the reset or inactive values of the new bits will always be 0. Port 1 also receives the low-order address bytes during Flash programming and verification. The Power Down Mode saves the RAM con- tents but freezes the oscillator, disabling all other chip func- tions until the next hardware reset. EA should attmel strapped to V.