T89C51AC2-RLSI-M datasheet(22/117 Pages) ATMEL

22 / 117 page

Draft.A - March 30, 2001

Preview - Confidential

T89C51AC2

7.4. Overview of FM0 operations

The CPU interfaces to the flash memory through the FCON register and AUXR1 register.

These registers are used to:

• Map the memory spaces in the adressable space

• Launch the programming of the memory spaces

• Get the status of the flash memory (busy/not busy)

• Select the flash memory FM0/FM1.

7.4.1. Mapping of the memory space

By default, the user space is accessed by MOVC instruction for read only. The column latches space is made

accessible by setting the FPS bit in FCON register. Writing is possible from 0000h to 7FFFh, address bits 6 to 0

are used to select an address within a page while bits 14 to 7 are used to select the programming address of the page.

Setting this bit takes precedence on the EXTRAM bit in AUXR register.

The other memory spaces (user, extra row, hardware security) are made accessible in the code segment by

programming bits FMOD0 and FMOD1 in FCON register in accordance with Table 13. A MOVC instruction is

then used for reading these spaces.

Table 13. .FM0 blocks select bits

7.4.2. Launching programming

FPL3:0 bits in FCON register are used to secure the launch of programming. A specific sequence must be written

in these bits to unlock the write protection and to launch the programming. This sequence is 5 followed by A.

Table 14 summarizes the memory spaces to program according to FMOD1:0 bits.

Table 14. Programming spaces

The FLASH memory enters a busy state as soon as programming is launched. In this state, the memory is no

more available for fetching code.

Caution:

Interrupts that may occur during programming time must be disable to avoid any spurious exit of the idle mode.

FMOD1

FMOD0

FM0 Adressable space

User (0000h-FFFFh)

Extra Row(FF80h-FFFFh)

Hardware Security (0000h)

reserved

Write to FCON

Operation

FPL3:0

FPS

FMOD1

FMOD0

User

No action

Write the column latches in user space

Extra Row

No action

Write the column latches in extra row space

Security Space

No action

Write the fuse bits space

Reserved

No action

T89C51AC2-RLSI-M 데이터시트(PDF) 22 Page - ATMEL Corporation

T89C51AC2-RLSI-M 데이터시트(HTML) 22 Page - ATMEL Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 ...More

데이터시트 다운로드

링크 URL