BQ26220 Datasheet, PDF (12/19 Pages) Texas Instruments – HIGH PERFORMANCE BATTERY MONITOR IC WITH COULOMB COUNTER, VOLTAGE AND TEMPERATURE MEASUREMENT

bq26220
SLUS521B − AUGUST 2002 − REVISED FEBRUARY 2004
APPLICATION INFORMATION
memory
ID ROM
Locations 0x7F through 0x78 contain the factory programmed ID ROM and also the LSB gain correction factor
for the voltage analog to digital converter. The format for this register is described in Table 5.
Table 5. ID ROM Command Code Summary
flash-shadowed RAM
BYTE
7
6
5
4
3
2
1
0
RAM LOCATION
0x7F
0x7E
0x7D
0x7C
0x7B
0x7A
0x79
0x78
INFORMATION
Device code 0x22
0x00
Random
Random
Random
Random
Gain correction factor
Random
NOTE:For additional information please contact Texas Instruments.
The host system has direct access to read and modify 32 bytes of RAM. These 32 bytes are shadowed by 32
bytes of flash to provide nonvolatile storage of battery conditions. The information stored in RAM is transferred
to flash, and the information stored in flash is transferred to RAM by writing a single command into the flash
command register (FCMD). When a power-on-reset occurs, page 0 of flash is transferred to RAM. For more
details, refer to the flash command register section.
user-flash memory
In addition to the flash-shadowed RAM, the bq26220 has 64 bytes of user-flash. The user-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 user-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 or
place the device into the low power mode. For more details, refer to the flash command register section.
Summaries of the flash command codes are shown in Table 6.
Table 6. Flash Command Code Summary
COMMAND CODE
(HEX)
0x0F
0x40
0x41
0x42
0x45
0x48
0xF6
DESCRIPTION
Program byte
Erase page 0 flash
Erase page 1 flash
Erase page 2 flash
Transfer page 0 RAM to page 0 flash
Transfer page 0 flash to page 0 RAM
Power down
12
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