T89C5115 ATMEL Corporation, T89C5115 Datasheet - Page 30

• Manufacturer Part Number: T89C5115
• Description: Low Pin Count 8-bit MCU with A/D Converter and 16-Kbytes of Flash Memory
• Manufacturer: ATMEL Corporation

FM0 Memory Architecture
User Space
Extra Row (XROW)
Hardware security Byte
Column Latches
Cross Flash Memory Access
Description
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T89C5115
The Flash memory is made up of 4 blocks (see Figure 11):
1. The memory array (user space) 16-KB.
2. The Extra Row.
3. The Hardware security bits.
4. The column latch registers.
This space is composed of a 16-KB Flash memory organized in 128 pages of 128 bytes.
It contains the user’s application code.
This row is a part of FM0 and has a size of 128 bytes. The extra row may contain infor-
mation for boot loader usage.
The Hardware Security Byte space is a part of FM0 and has a size of 1 byte.
The 4 MSB can be read/written by software, the 4 LSB can only be read by software and
written by hardware in parallel mode.
The column latches, also part of FM0, have a size of full page (128 bytes).
The column latches are the entrance buffers of the three previous memory locations
(user array, XROW and Hardware security byte).
The FM0 memory can be program only from FM1. Programming FM0 from FM0 or from
external memory is impossible.
The FM1 memory can be program only by parallel programming.
The Table 19 show all software flash access allowed.
Table 19. Cross Flash Memory Access
(user Flash)
(boot flash)
FM0
FM1
Load column latch
Load column latch
Action
Read
Read
Write
Write
(user Flash)
FM0
ok
ok
ok
ok
ok
-
(boot Flash)
4128A–8051–04/02
FM1
ok
-
-
-
-
-