Texas Instruments BQ28Z610-R2 Technical Reference Manual Download

Page: 72 / 133

The length byte for all MAC commands will include the 2-byte command, the 1-byte checksum, the 1-byte length,
and 1 to 32 bytes of data. This means the minimum length value is 5 for a valid block (no length or checksum is
used for command only writes, so block of zero size is not necessary). For proper write command validation, the
checksum and length must be written in order (word access triggered).

12.2 Manufacturer Access Control (MAC)

The Manufacturer Access Control (MAC) system provides method for accessing subcommands to read and write
data, and to control the device state.

The subcommands are set by a valid word access to either the

ManufacturerAccess()

MACSubcmd()

commands. For subcommands without data arguments, setting the subcommand alone will trigger execution.
For subcommands with data the

MACData()

MACDataChecksum()

and

MACDataLength()

are used to write

the subcommand arguments and trigger execution of the subcommand, or to read and validate the response
after setting the subcommand. These can be accessed either in a single I2C transaction or split into multiple
transactions as long as the access starts with the lowest address and ends at the highest, without other
unrelated commands interleaved.

For subcommands with a data response, it is recommended to read back the

MACSubcmd()

registers to

confirm the

MACData()

information comes from the intended command. There is no read back verification for

subcommands that execute without any data arguments.

Example: Send a MAC

Gauging()

to enable IT via

MACSubcmd().

1. With Impedance Track disabled, send

Gauging()

(0x0021) to

MACSubcmd()

a. I

C Write, start address = 0x3E (or 0x00). Data = 21 00 (data must be sent in Little Endian).

2. IT is enabled,

ManufacturingStatus()[GAUGE_EN]

= 1.

Example: Read

Chemical ID()

(0x0006) via

MACSubcmd().

1. Send

Chemical ID()

MACSubcmd().

a. I

C Write, start address = 0x3E (or 0x00). Data sent = 06 00 (data must be sent in Little Endian).

2. Read the result from

MACSubcmd()

and

MfgMACData()

a. I

C Read, start address = 0x3E length = 36 bytes. First 4 bytes of the response will be 06 00 10 12.

b. The first two bytes "06 00" is the MAC command (for verification).
c. The second two bytes "10 12" are the Chem ID in Little Endian. That is, 0x1210 for ChemID 1210.
d. The last two bytes of the 36-byte block will be the checksum and length. The length in this case will be

6. The checksum is 0xFF – (sum of the first length – 2 bytes). The length and checksum are used to
validate the block response.

It is recommended to send “command only” operations to

ManufacturerAccess()

on 0x00 and 0x01, as this

works with legacy devices as well as newer devices and also can reset any legacy compatibility options in effect;
whereas, some legacy devices use 0x3E and 0x3F for other purposes. The 0x3E and 0x3F can always be used
for reads. When no legacy devices are expected to be present, 0x3E and 0x3F

MACSubcmd()

can safely be

used to optimize command execution.

To support detection of legacy devices, a request for the MAC subcommands DEV and VERSION written
to 0x00 and 0x01 will cause the

ControlStatus()

read to report 0xFFA5. This token indicates that the

device supports MAC on the 0x3E–0x61 command range and to go there for the response. In addition, the

MACDataLengh()

minimum valid value is 5 to allow some devices to have legacy support triggers when writing

other values from 0–4 to this command.

Table 12-2. MACSubcmd() Command List

Command