AT89LP51ED2-20MU Atmel, AT89LP51ED2-20MU Datasheet - Page 186

• Manufacturer Part Number: AT89LP51ED2-20MU
• Description: 8-bit Microcontrollers - MCU 64KB 20MHz 2.4V-5.5V
• Manufacturer: Atmel

Specifications of AT89LP51ED2-20MU

• Rohs: yes
• Core: 8051
• Data Bus Width: 8 bit
• Maximum Clock Frequency: 20 MHz
• Program Memory Size: 64 KB
• Data Ram Size: 256 B
• On-chip Adc: Yes
• Operating Supply Voltage: 2.4 V to 5.5 V
• Operating Temperature Range: - 40 C to + 85 C
• Package / Case: VQFN-44
• Mounting Style: SMD/SMT
• Data Rom Size: 4 KB
• Interface Type: 2-Wire, SPI, UART
• Number Of Programmable I/os: 36
• Number Of Timers: 3
• Processor Series: AT89x
• Program Memory Type: Flash
• Factory Pack Quantity: 360

23.2
23.3
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Software Breakpoints
Limitations of On-Chip Debug
AT89LP51RD2/ED2/ID2 Preliminary
The AT89LP51RD2/ED2/ID2 microcontroller includes a BREAK instruction for implementing
program memory breakpoints in software. A software breakpoint can be inserted manually by
placing the BREAK instruction in the program code. Some emulator systems may allow for auto-
matic insertion/deletion of software breakpoints. The Flash memory must be re-programmed
each time a software breakpoint is changed. Frequent insertions/deletions of software break-
points will reduce the endurance of the nonvolatile memory. Devices used for debugging
purposes should not be shipped to end customers. The BREAK instruction is treated as a two-
cycle NOP when OCD is disabled.
The AT89LP51RD2/ED2/ID2 is a fully-featured microcontroller that multiplexes several functions
on its limited I/O pins. Some device functionality must be sacrificed to provide resources for On-
Chip Debugging. The On-Chip Debug System has the following limitations:
• The Debug Clock pin (DCL) is physically located on the same pin as the External Reset
• The Debug Data pin DDA is physically located on the same pin as P4.3. The P4.3 I/O
• The bootloader has priority over OCD. Debugging is not possible when the bootloader is
• Programming of any hardware lockbit will disable OCD
• The OCD pins are not bonded in the 40-pin PDIP package. In order to debug the device, one
(RST). Therefore, an external reset source is unavailable and must be emulated when OCD
is enabled. The Reset Output feature is also disabled except during POR
function cannot be emulated in this mode
active (BLJB = 0 or hardware entry triggered)
of the 44-pin packages must be used
3714A–MICRO–7/11