BQ2019PW Datasheet, PDF (12/27 Pages) Texas Instruments – ADVANCED BATTERY MONITORIC

bq2019
ADVANCED BATTERY MONITOR IC
SLUS465E – DECEMBER 1999 – REVISED FEBRUARY 2003
APPLICATION INFORMATION
memory (continued)
flash memory
In addition to the flash-shadowed RAM, the bq2019 has 64 bytes of flash. The flash can store specific battery
pack parameters, such as charge per VFC pulse, battery chemistry, and self-discharge rates.
flash programming
The two banks of direct flash are programmed one byte at a time, but the single bank of flash-shadowed RAM
can be programmed one page at a time or by writing the RAM-to-flash transfer code into the flash command
register (FCMD). This programming is performed by writing the desired code into the flash command register,
FCMD (address 0x62), the host may transfer data between flash and RAM, page erase the flash, place the
device into the low power mode, or perform VFC offset measurement. For more details, refer to the flash
command register section. Summaries of the flash command codes are shown in Table 5.
Table 5. Flash Command Code Summary
COMMAND CODE
(HEX)
0x0F
0x40
0x41
0x42
0x43
0x45
0x48
0xF6
0xF7
DESCRIPTION
Program byte
Erase page 0 flash
Erase page 1 flash
Erase page 2 flash
Erase offset control shadow flash
Transfer page 0 RAM to page 0 flash
Transfer page 0 flash to page 0 RAM
Power down
Calibrate VFC and power down
single-byte programming
To program an individual byte in flash, the byte of data is first written into the FPD register while the address
to be programmed is written into the FPA register. The program byte command, 0x0F is then written to the
FCMD. The result of this sequence is that the contents of the FPD register are logically ANDed with the contents
of the flash address pointed to by the FPA register.
RAM-to-flash transfer
The content of the flash that shadows the user RAM is logically ANDed to the RAM contents when the
RAM-to-flash transfer command is sent. If new data are to be written over old data, then it is necessary to first
erase the flash page that is being updated and restore all necessary data.
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