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Standard 8051 8-Bit Flash MCU
HT85F2260/HT85F2270/HT85F2280
Flash Program Memory
Flash Program Memory
In-Application Programming – IAP
An In-Application Programming interface is provided to allow the end user’s application to erase
and reprogram the user code memory. No extra code memory block (bootloader) is required to
update the firmware or non-volatile data. Firmware for the IAP and the code memory to be updated
are physically on the same IP. Users could update firmware or non-volatile data except for the sector
where IAP is located and run. A firmware library is used to provide APIs for flash programming.
Flash Program Memory Resisters
With regard to the Flash Program Memory registers, there are three address registers, one 8-bit
data register and three control registers, located in the Special Function Registers. Read and Write
operations to the Flash memory are carried out in 8-bit data operations using the address and data
registers and the control registers. The address registers are named FMAR0, FMAR1 and FMAR2,
the data register is named FMDR, and the three control registers are named FMKEY, FMCR
and FMSR. As these registers are located in Special Function Register area, they can be directly
accessed in the same was as any other Special Function Register.
Program Memory Register List
Name
Bit
7
6
5
4
3
2
1
0
FMAR0
FADDR7
FADDR6
FADDR�
FADDR4
FADDR3
FADDR�
FADDR1
FADDR0
FMAR1
FADDR1� FADDR14 FADDR13 FADDR1� FADDR11 FADDR10
FADDR9
FADDR8
FMAR�
INBLK
FADDR�� FADDR�1 FADDR�0 FADDR19 FADDR18 FADDR17 FADDR16
FMDR
FDAT7
FDAT6
FDAT�
FDAT4
FDAT3
FDAT�
FDAT1
FDAT0
FMKEY
FMKEY7
FMKEY6
FMKEY�
FMKEY4
FMKEY3
FMKEY�
FMKEY1
FMKEY0
FMCR
FMCR.7
FMCR.6
—
—
—
FMCR.�
FMCR.1
FMCR.0
FMSR
UNLOCK
—
—
—
FMPF
FMSEF
FMBF
FMBUSY
FMAR0 Register – Flash Program Memory Address Register 0
SFR Address: FAh
Bit
7
6
5
4
3
2
1
0
Name
FADDR7
FADDR6
FADDR�
FADDR4
FADDR3
FADDR�
FADDR1
FADDR0
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
POR
0
0
0
0
0
0
0
0
Bit 7~0
Flash Program Memory address
Flash Program Memory address bit 7~bit 0