Rainbow Electronics T89C51RD2 - Manual (Page 51)

51 Rev. F - 15 February, 2001
T89C51RD2
The bootloader and the In Application Programming (IAP) routines are located in the last kilobyte of the FLASH,
leaving 63k bytes available for the application with ISP.
8.4. FLASH registers and memory map
The T89C51RD2 FLASH memory uses several registers for his management:
•
Flash control register is used to select the Flash memory spaces and launch the Flash programming sequence.
•
Hardware registers can only be accessed through the parallel programming modes which are handled by the
parallel programmer.
•
Software registers are in a special page of the FLASH memory which can be accessed through the API or with
the parallel programming modes. This page, called "Extra FLASH Memory", is not in the internal FLASH
program memory addressing space.
8.4.1. FLASH register
FCON (S:D1h)
FLASH control register
Reset Value = xxxx 0000b
Figure 18. FCON register
The Flash programming application note and API source code are available on request.
8.4.2. Hardware register
The only hardware register of the T89C51RD2 is called Hardware Security Byte (HSB). After full FLASH erasure,
the content of this byte is FFh; each bit is active at low level.
7 6 5 4 3 2 1 0
FPL3 FPL2 FPL1 FPL0 FPS FMOD1 FMOD0 FBUSY
Bit Number Bit Mnemonic Description
7-4 FPL3:0
Programming Launch command bits
Write 5h followed by Ah to launch the programming.
3 FPS
FLASH Map Program Space
Clear to map the data space during MOVX
Set to map the FLASH space during MOVX (write) or MOVC (read) instructions (Write in the
column latches)
2-1 FMOD1:0
FLASH Mode
Select the addressed space
00: User (0000h-FFFFh)
01: XAF
10: Hardware byte
11: reserved
0 FBUSY
FLASH Busy
Set by hardware when programming is in progress.
Clear by hardware when programming is done.
Can not be cleared by software