t89c51rd2-slscl ATMEL Corporation, t89c51rd2-slscl Datasheet - Page 53

• Manufacturer Part Number: t89c51rd2-slscl
• Description: 0 To 40 Mhz Flash Programmable 8-bit Microcontroller
• Manufacturer: ATMEL Corporation

Flash EEPROM Memory
General Description
Features
Flash Programming and
Erasure
4243G–8051–05/03
The Flash memory increases EPROM and ROM functionality with in-circuit electrical
erasure and programming. It contains 64K bytes of program memory organized in 512
pages of 128 bytes. This memory is both parallel and serial In-System Programmable
(ISP). ISP allows devices to alter their own program memory in the actual end product
under software control. A default serial loader (bootloader) program allows ISP of the
Flash.
The programming does not require 12v external programming voltage. The necessary
high programming voltage is generated on-chip using the standard V
microcontroller.
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The 64K bytes Flash is programmed by bytes or by pages of 128 bytes. It is not neces-
sary to erase a byte or a page before programming. The programming of a byte or a
page includes a self erase before programming.
There are three methods to program the Flash memory:
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Flash E2PROM internal program memory.
The last 1K bytes of the Flash is used to store the low-level in-system programming
routines and a default serial loader. If the application does not need to use the ISP
and does not expect to modify the Flash content, the Boot Flash sector can be
erased to provide access to the full 64K byte Flash memory.
Boot vector allows user provided Flash loader code to reside anywhere in the Flash
memory space. This configuration provides flexibility to the user.
Default loader in Boot Flash allows programming via the serial port without the need
of a user provided loader.
Up to 64K byte external program memory if the internal program memory is disabled
(EA = 0).
Programming and erase voltage with standard 5V or 3V V
Read/Programming/Erase:
Byte-wise read (without wait state).
Byte or page erase and programming (10 ms).
Typical programming time (63K bytes) in 20 s.
Parallel programming with 87C51 compatible hardware interface to programmer.
Programmable security for the code in the Flash.
100k write cycles
10 years data retention
First, the on-chip ISP bootloader may be invoked which will use low level routines to
program the pages. The interface used for serial downloading of Flash is the UART.
Second, the Flash may be programmed or erased in the end-user application by
calling low-level routines through a common entry point in the Boot loader.
Third, the Flash may be programmed using the parallel method by using a
conventional EPROM programmer. The parallel programming method used by
CC
T89C51RD2
supply.
CC
pins of the
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