TI1 BQ2024 1.5k-bit serial eprom with sdq interface Datasheet

bq2024
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SLUS770 – MAY 2007
1.5K-BIT SERIAL EPROM WITH SDQ INTERFACE
Check for Samples: bq2024
FEATURES
DESCRIPTION
•
The bq2024 is a 1.5K-bit serial EPROM containing a
factory-programmed, unique 48-bit identification
number, 8-bit CRC generation, and the 8-bit family
code (09h). A 64-bit status register controls write
protection and page redirection.
1
2
•
•
•
•
•
•
•
•
•
•
1536 Bits of One-Time Programmable (OTP)
EPROM For Storage Of User-Programmable
Configuration Data
Factory-Programmed Unique 64-Bit
Identification Number
Bus-Interface Architecture Allowing Multiple
bq2024's Attached to a Single Host
Single-Wire Interface to Reduce Circuit Board
Routing
Synchronous Communication Reduces Host
Interrupt Overhead
No Standby Power Required
Address Space Backward Compatible With
bq2022A
8-byte RAM Buffer for Faster Write
Page Address Redirection
15KV IEC 61000-4-2 Air Charge on SDQ
Available in a 3-Pin SOT23 Package and TO-92
Package
The bq2024 SDQ™ interface requires only a single
connection and a ground return. The DATA pin is
also the sole power source for the bq2024. The bus
architecture allows multiple SDQ devices to be
connected to a single host.
The small surface-mount package options saves
printed-circuit-board space, while the low cost makes
it ideal for applications such as battery pack
configuration parameters, record maintenance, asset
tracking, product-revision status, and access-code
security.
ORDERING INFORMATION (1)
TA
–20°C to
70°C
APPLICATIONS
•
•
•
•
(1)
Security Encoding
Inventory Tracking
Product-Revision Maintenance
Battery-Pack Identification
(2)
(3)
PACKAGED DEVICES (3)
(2)
PART NUMBER
PACKAGE
STATUS
bq2024DBZR
SOT23-3
Production
bq2024LPR
TO-92
Preview
For the most current package and ordering information, see
the Package Option Addendum at the end of this document,
or see the TI Web site at www.ti.com.
Device specified to communicate at –40°C to 85°C.
The device is available only in tape and reel with a base
quantity of 3000 units for the bq2024DBZR and 2000 units for
the bq2024LPR.
BLOCK DIAGRAM
DBZ PACKAGE
(TOP VIEW)
SDQ
SDQ
VSS
1
SDQ Communications
Controller and 8-Bit CRC
Generation Circuit
Internal
Bus
bq2024
RAM
Buffer
(8 bytes)
EPROM
STATUS
(64 bits)
VSS
3
ID ROM
(64 bits)
VSS
EPROM
MEMORY
(1536 bits)
2
1
2
LP PACKAGE
(BOTTOM VIEW)
3
VSS
1
VSS
2
SDQ
3
NC
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
SDQ is a trademark of Texas Instruments.
UNLESS OTHERWISE NOTED this document contains
PRODUCTION DATA information current as of publication date.
Products conform to specifications per the terms of Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2007, Texas Instruments Incorporated
bq2024
SLUS770 – MAY 2007
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This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
ABSOLUTE MAXIMUM RATINGS
over operating free-air temperature range unless otherwise noted (1)
UNIT
VPU
DC voltage applied to data
IOL
Low-level output current
–0.3 V to 7 V
40 mA
ESD IEC 61000-4-2 Air discharge
Data to VSS, VSS to data
TA
Operating free-air temperature range
TA(Comm)
Communication free-air temperature range
Tstg
Storage temperature range
15 kV
–20°C to 70°C
Communication is specified by design
–40°C to 85°C
–55°C to 125°C
Lead temperature (soldering, 10 s)
(1)
260°C
Stresses beyond those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating
conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.
DC ELECTRICAL CHARACTERISTICS
TA = –20°C to 70°C; VPU(min) = 2.65 VDC to 5.5 VDC, all voltages relative to VSS
PARAMETER
TEST CONDITION
IDATA
Supply current
VOL
Low-level output voltage
VOH
High-level output voltage
Logic 1
IOL
Low-level output current (sink)
VOL = 0.4 V, SDQ pin
VIL
Low-level input voltage
Logic 0
VIH
High-level input voltage
Logic 1
VPP
Programming voltage
MIN
TYP
MAX
VPU = 5.5 V
20
Logic 0, VPU = 5.5 V, IOL = 4 mA, SDQ pin
0.4
Logic 0, VPU = 2.65 V, IOL = 2 mA
0.4
VPU
UNIT
μA
V
5.5
4
0.8
2.2
mA
V
V
11.5
12
V
AC SWITCHING CHARACTERISTCS
TA = –20°C to 70°C; VPU(min) = 2.65 VDC to 5.5 VDC, all voltages relative to VSS
PARAMETER
tc
Bit cycle time (1)
tWSTRB
Write start cycle
tWDSU
Write data setup
tWDH
Write data hold (1) (2)
trec
Recovery time (1)
tRSTRB
Read start cycle (1)
tODD
Output data delay
tODHO
Output data hold (1)
tRST
Reset time (1)
tPPD
Presence pulse delay (1)
tPP
Presence pulse
tEPROG
EPROM programming time
tPSU
Program setup time
(1)
(2)
2
TEST CONDITION
(1)
(1)
MIN
MAX
UNIT
60
TYP
120
μs
1
15
μs
tWSTRB
15
μs
60
tc
μs
1
For memory command only
(1)
μs
5
1
13
μs
tRSTRB
13
μs
17
60
μs
μs
480
(1)
15
60
μs
60
240
μs
2500
μs
5
μs
5-kΩ series resistor between SDQ pin and VPU. (See Figure 1)
tWDH must be less than tc to account for recovery.
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AC SWITCHING CHARACTERISTCS (continued)
TA = –20°C to 70°C; VPU(min) = 2.65 VDC to 5.5 VDC, all voltages relative to VSS
PARAMETER
TEST CONDITION
MIN
TYP
MAX
UNIT
μs
tPREC
Program recovery time
tPRE
Program rising-edge time
5
5
μs
tPFE
Program falling-edge time
5
μs
tRSTREC
480
μs
Terminal Functions
TERMINAL
NAME
I/O
NO.
DESCRIPTION
bq2024DBZR
SDQ
1
I
Data
VSS
2, 3
-
Ground
-
GND
bq2024LPR, bq2024LPFR
VSS
1
SDQ
2
I
Data
NC
3
-
No connection
FUNCTIONAL DESCRIPTION
GENERAL OPERATION
The block diagram on page 1 shows the relationships among the major control and memory sections of the
bq2024. The bq2024 has three main data components: a 1536-bit factory-programmed ROM, including 8-bit
family code, 48-bit identification number and 8-bit CRC value, EPROM, and EPROM STATUS bytes. Power for
read and write operations is derived from the DATA pin. An internal capacitor stores energy while the signal line
is high and releases energy during the low times of the DATA pin, until the pin returns high to replenish the
charge on the capacitor. A special manufacturer's PROGRAM PROFILE BYTE can be read to determine the
programming profile required to program the part.
1536-BIT EPROM
Table 1 is a memory map of the 1536-bit EPROM section of the bq2024, configured as six pages of 32 bytes
each. The 8-byte RAM buffers are additional registers used when programming the memory. Data are first
written to the RAM buffer and then verified by reading an 8-bit CRC from the bq2024 that confirms proper receipt
of the data. If the buffer contents are correct, a programming command is issued and an 8-byte segment of data
is written into the selected address in memory. This process ensures data integrity when programming the
memory. The details for reading and programming the 1536-bit EPROM portion of the bq2024 are in the Memory
Function Commands section of this data sheet.
Table 1. 1536-BIT EPROM Data Memory Map
ADDRESS(HEX)
PAGE
00A0-00BF
Page 5
0080-009F
Page 4
0060-007F
Page 3
0040-005F
Page 2
0020-003F
Page 1
0000-001F
Page 0
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EPROM STATUS MEMORY
In addition to the programmable 1536 bits of memory, there are 64 bits of status information contained in the
EPROM STATUS memory. The STATUS memory is accessible with separate commands. The STATUS bits are
EPROM and are read or programmed to indicate various conditions to the software interrogating the bq2024.
The first byte of the STATUS memory contains the write protect page bits, that inhibit programming of the
corresponding page in the 1536-bit main memory area if the appropriate write-protection bit is programmed.
Once a bit has been programmed in the write protect page byte, the entire 32-byte page that corresponds to that
bit can no longer be altered but may still be read. The write protect bits may be cleared by using the WRITE
STATUS command.
The next six bytes of the EPROM STATUS memory contain the page address redirection bytes. Bits in the
EPROM status bytes can indicate to the host what page is substituted for the page by the appropriate redirection
byte. The hardware of the bq2024 makes no decisions based on the contents of the page address redirection
bytes. This feature allows the user's software to make a data patch to the EPROM by indicating that a particular
page or pages should be replaced with those indicated in the page address redirection bytes. The ones
complement of the new page address is written into the page address redirection byte that corresponds to the
original (replaced) page. If a page address redirection byte has an FFh value, the data in the main memory that
corresponds to that page are valid. If a page address redirection byte has some other hex value, the data in the
page corresponding to that redirection byte are invalid, and the valid data can now be found at the ones
complement of the page address indicated by the hexadecimal value stored in the associated page address
redirection byte. A value of FDh in the redirection byte for page 1, for example, indicates that the updated data
are now in page 2. The details for reading and programming the EPROM status memory portion of the bq2024
are given in the Memory Function Commands section.
Table 2. EPROM Status Bytes
ADDRESS (HEX)
PAGE
00h
Write protection bits
BIT0 - write protect page 0
BIT1 - write protect page 1
BIT2 - write protect page 2
BIT3 - write protect page 3
BIT4 -write protect page 4
BIT5 -write protect page 5
BIT6 to 7 -bitmap of used pages
01h
Redirection byte for page 0
02h
Redirection byte for page 1
03h
Redirection byte for page 2
04h
Redirection byte for page 3
05h
Redirection byte for page 4
06h
Redirection byte for page 5
07h
Factory programmed 00h
Error Checking
To validate the data transmitted from the bq2024, the host generates a CRC value from the data as they are
received. This generated value is compared to the CRC value transmitted by the bq2024. If the two CRC values
match, the transmission is error-free. The equivalent polynomial function of this CRC is X8 + X5 + X4 + 1. Details
are found in the CRC Generation Section of this data sheet.
Customizing the bq2024
The 64-bit ID identifies each bq2024. The 48-bit serial number is unique and programmed by Texas Instruments.
The default 8-bit family code is 09h; however, a different value can be reserved on an individual customer basis.
Contact your Texas Instruments sales representative for more information.
Bus Termination
Because the drive output of the bq2024 is an open-drain, N-channel MOSFET, the host must provide a source
current or a 5-kΩ external pullup, as shown in the typical application circuit in Figure 1.
4
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VPU
bq2024
SDQ
SDQI
1
Communications
Controller
CPU
SDQO
VSS
2
VSS
3
HOST
Figure 1. Typical Applications Circuit
Serial Communication
A host reads, programs, or checks the status of the bq2024 through the hierarchical command structure of the
SDQ interface. Figure 2 shows that the host must first issue a ROM command before the EPROM memory or
status can be read or modified. The ROM command either selects a specific device when multiple devices are on
the SDQ bus, or skips the selection process in single SDQ device applications.
Initialization
ROM Command Sequence
Memory/Status Command Sequence
Figure 2. General Command Sequence
Initialization
Initialization consists of two pulses, the RESET and the PRESENCE pulses. The host generates the RESET
pulse, while the bq2024 responds with the PRESENCE pulse. The host resets the bq2024 by driving the DATA
bus low for at least 480 μs. For more details, see the RESET section under SDQ Signaling.
ROM COMMANDS
READ ROM
The READ ROM command sequence is the fastest sequence that allows the host to read the 8-bit family code
and 48-bit identification number. It is used if only one SDQ slave device is attached to the bus. The READ ROM
sequence starts with the host generating the RESET pulse of at least 480 μs. The bq2024 responds with a
PRESENCE pulse. Next, the host continues by issuing the READ ROM command, 33h, and then reads the ROM
and CRC byte using the READ signaling (see the READ and WRITE signals section) during the data frame.
Reset
and
Presence
Signals
1
1
Read ROM (33h)
0
0
1
1
0
0
Family Code and Identification
Number (7 BYTES)
CRC (1 BYTE)
Figure 3. READ ROM Sequence
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MATCH ROM
The MATCH ROM command, 55h, is used by the host to select a specific SDQ device when the family code and
identification number is known. The host issues the MATCH ROM command followed by the family code, ROM
number, and the CRC byte. Only the device that matches the 64-bit ROM sequence is selected and available to
perform subsequent Memory/Status Function commands.
Reset
and
Presence
Signals
1
Match ROM (55h)
1
0
1
0
0
1
Family Code and Identification
Number (7 BYTES)
0
CRC (1 BYTE)
Figure 4. MATCH ROM Sequence
SEARCH ROM
The SEARCH ROM command, F0h, is used to obtain the 8-bit family code and the 48-bit identification number
and 8-bit CRC of any SDQ device when it is unknown. All devices on the bus are read under the SEARCH ROM
command with the use of a collision-detect and device-decode method. Figure 5 shows the SEARCH ROM
sequence started by the host, generating the RESET pulse of at least 480 μs. The bq2024 responds with a
PRESENCE pulse. The host then issues the command in the command frame by writing an F0h. During the
DATA READ of the SEARCH ROM sequence, each bit is transmitted three times. The bq2024 transmits the bit
followed by the complement of the bit. The host in turn retransmits the bit just read. Collision detection is
performed by comparing the bit and bit complement time-slots. If they are both zero, this indicates that a collision
has occurred, indicating multiple devices on the bus. The device decode is achieved in the third transmission of
the bit from the host back to the bq2024. If the bit transmitted by the host does not match the bit transmitted by
the bq2024, then the device with mismatch stops transmitting. Devices that did match, continue transmitting. This
process is continued until all bits of a single device are read. The SEARCH ROM command is reissued and the
process is repeated to read additional devices.
NOTE
If the number of devices on the bus is unknown, the SEARCH ROM command should be
used.
Reset
and
Presence
Signals
Data Read
Search ROM (F0h)
0
0
0
0
1
1
1
1
A.
B = bit( n): nth bit transmitted by bq2024
B.
C = bit( n) : complement of nth bit transmitted by bq2024
C.
H = bit( n): nth bit transmitted by host
BIT0
BITn
BIT63
Figure 5. SEARCH ROM Sequence
6
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SKIP ROM
This SKIP ROM command, CCh, allows the host to access the memory/status functions without issuing the 64-bit
ROM code sequence. The SKIP ROM command is directly followed by a memory/status functions command.
Because this command can cause bus collisions when multiple SDQ devices are on the same bus, this
command should be issued in single device applications.
Reset
and
Presence
Signals
Skip ROM (CCh)
0
1
0
1
0
1
0
1
Figure 6. SKIP ROM Sequence
MEMORY/STATUS FUNCTION COMMANDS
Six memory/status function commands allow read and modification of the 1536-bit EPROM data memory or the
64-bit EPROM status memory. There are two types of READ MEMORY command, plus the WRITE MEMORY,
READ STATUS, and WRITE STATUS commands. Additionally, the part responds to a PROGRAM PROFILE
byte command. The bq2024 responds to memory/status function commands only after a part is selected by a
ROM command.
READ DATA MEMORY COMMANDS
Two READ MEMORY commands are available on the bq2024. Both commands are used to read data from the
1536-bit EPROM data field. They are the READ MEMORY/Page CRC and the READ MEMORY/Field CRC
commands. The READ MEMORY/Page CRC generates CRC at the end any 32-byte page boundary whereas
the READ MEMORY/Field CRC generates CRC when the end of the 1536-bit data memory is reached.
READ MEMORY/Page CRC
To read memory and generate the CRC at the 32-byte page boundaries of the bq2024, the ROM command is
followed by the READ MEMORY/Generate CRC command, C3h, followed by the address low byte and then the
address high byte.
An 8-bit CRC of the command byte and address bytes is computed by the bq2024 and read back by the host to
confirm that the correct command word and starting address were received. If the CRC read by the host is
incorrect, a reset pulse must be issued and the entire sequence must be repeated. If the CRC received by the
host is correct, the host issues read time slots and receives data from the bq2024 starting at the initial address
and continuing until the end of a 32-byte page is reached. At that point, the host sends eight additional read time
slots and receive an 8-bit CRC that is the result of shifting into the CRC generator all of the data bytes from the
initial starting byte to the last byte of the current page. Once the 8-bit CRC has been received, data is again read
from the 1536-bit EPROM data field starting at the next page. This sequence continues until the final page and
its accompanying CRC are read by the host. Thus each page of data can be considered to be 33 bytes long, the
32 bytes of user-programmed EPROM data and an 8-bit CRC that gets generated automatically at the end of
each page.
Initialization and ROM
Command Sequence
READ
MEMORY/Generate
CRC Command
C3h
Address Low Byte
A0
Address High
Byte
A7 A8
A15
Read and
Verify CRC
EPROM Memory and
CRC Byte
Generated at 32-Byte
Page
Boundaries
NOTE: Individual bytes of address and data are transmitted LSB first.
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Figure 7. READ MEMORY/Page CRC
8
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READ MEMORY/Field CRC
To read memory without CRC generation on 32-byte page boundaries, the ROM command is followed by the
READ MEMORY command, F0h, followed by the address low byte and then the address high byte.
NOTE
As shown in Figure 8, individual bytes of address and data are transmitted LSB first.
An 8-bit CRC of the command byte and address bytes is computed by the bq2024 and read back by the host to
confirm that the correct command word and starting address were received. If the CRC read by the host is
incorrect, a reset pulse must be issued and the entire sequence must be repeated. If the CRC received by the
host is correct, the host issues read time slots and receives data from the bq2024 starting at the initial address
and continuing until the end of the 1536-bit data field is reached or until a reset pulse is issued. If reading occurs
through the end of memory space, the host may issue eight additional read time slots and the bq2024 responds
with an 8-bit CRC of all data bytes read from the initial starting byte through the last byte of memory. After the
CRC is received by the host, any subsequent read time slots appear as logical 1s until a reset pulse is issued.
Any reads ended by a reset pulse prior to reaching the end of memory does not have the 8-bit CRC available.
Initialization and ROM
Command
Sequence
READ MEMORY Command
F0h
Address Low
Byte
A0
Address High
Byte
A7 A8
Read and
Verify
CRC
Read EPROM
Memory Until
End of EPROM
Memory
Read and
Verify CRC
A15
Figure 8. READ MEMORY/Field CRC
WRITE MEMORY
The WRITE MEMORY command is used to program the 1536-bit EPROM memory field. The 1536-bit memory
field is programmed in 8-byte segments. Data is first written into an 8-byte RAM buffer one byte at a time. The
contents of the RAM buffer is then ANDed with the contents of the EPROM memory field when the programming
command is issued.
Figure 9 illustrates the sequence of events for programming the EPROM memory field. After issuing a ROM
command, the host issues the WRITE MEMORY command, 0Fh, followed by the low byte and then the high byte
of the starting address. The bq2024 calculates and transmits an 8-bit CRC based on the WRITE command and
address.
If at any time during the WRITE MEMORY process, the CRC read by the host is incorrect, a reset pulse must be
issued, and the entire sequence must be repeated.
After the bq2024 transmits the CRC, the host then transmits 8 bytes of data to the bq2024. Another 8-bit CRC is
calculated and transmitted based on the 8 bytes of data. If this CRC agrees with the CRC calculated by the host,
the host transmits the program command 5Ah and then applies the programming voltage for at least 2500 μs or
tEPROG. The contents of the RAM buffer is then logically ANDed with the contents of the 8-byte EPROM offset by
the starting address.
The starting address can be any integer multiple of eight between 0000 and 00BF (hex) such as 0000, 0008, and
0010 (hex).
The WRITE DATA MEMORY command sequence can be terminated at any point by issuing a reset pulse except
during the program pulse period tPROG.
NOTE
The bq2024 responds with the data from the selected EPROM address sent least
significant-bit first. This response should be checked to verify the programmed byte. If the
programmed byte is incorrect, then the host must reset the part and begin the write
sequence again.
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For both of these cases, the decision to continue programming is made entirely by the host, because the bq2024
is not able to determine if the 8-bit CRC calculated by the host agrees with the 8-bit CRC calculated by the
bq2024.
Prior to programming, bits in the 1536-bit EPROM data field appear as logical 1s.
Write Memory
Command?
(0Fh)
Selected
State
N
Selected
State
Y
Bus Master Transmits Low Byte Address
(LSB First) AD0 to AD7
Bus Master Transmits High Byte Address
(LSB First) AD8 to AD15
bq2024
Loads Address Into Address Counter
bq2024 Transmits CRC of Write Command
and Address, then Clears CRC Register
bq2024 Receives 8 Bytes of Data and
Stores in RAM Buffer
bq2024 Transmits
CRC of Previous Received 8 Bytes of Data
N
Code 5Ah
Received
Y
Voltage on Data
Pin = VPP
N
Y
Contents of RAM buffer AND’ed with contents of
data memory offset by
address counter and stored in data
memory offset by address counter .
programming time required to be at
least t EPROG when VPP Vdc on data pin
bq2024
Increments Address
Counter and Transmits 1
Byte of Data Memory
Indexed by Address Counter
bq2024
8th Byte
Transmitted
Transmits 1 Byte of Data Memory
at Address Counter
N
Y
bq2024 Waits for Reset
(No Further Response)
NOTE: Individual bytes of address and data are transmitted LSB first
Figure 9. WRITE MEMORY Command Flow
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READ STATUS
The READ STATUS command is used to read data from the EPROM status data field. After issuing a ROM
command, the host issues the READ STATUS command, AAh, followed by the address low byte and then the
address high byte.
NOTE
An 8-bit CRC of the command byte and address bytes is computed by the bq2024 and
read back by the host to confirm that the correct command word and starting address
were received.
If the CRC read by the host is incorrect, a reset pulse must be issued and the entire sequence must be repeated.
If the CRC received by the host is correct, the host issues read time slots and receives data from the bq2024
starting at the supplied address and continuing until the end of the EPROM Status data field is reached. At that
point, the host receives an 8-bit CRC that is the result of shifting into the CRC generator all of the data bytes
from the initial starting byte through the final factory-programmed byte that contains the 00h value.
This feature is provided because the EPROM status information may change over time making it impossible to
program the data once and include an accompanying CRC that is always valid. Therefore, the READ status
command supplies an 8-bit CRC that is based on (and always is consistent with) the current data stored in the
EPROM status data field.
After the 8-bit CRC is read, the host receives logical 1s from the bq2024 until a reset pulse is issued. The READ
STATUS command sequence can be ended at any point by issuing a reset pulse.
Initialization and ROM
Command
Sequence
READ MEMORY Command
AAh
Address Low
Byte
A0
Address High
Byte
A7 A8
Read and
Verify
CRC
Read STATUS
Memory Until
End of STATUS
Memory
Read and
Verify CRC
A15
Figure 10. READ STATUS Command
WRITE STATUS
The Write Status command is used to program the EPROM Status data field after the bq2024 has been selected
by a ROM command
The flow chart in Figure 11 illustrates that the host issues the Write Status command, 55h, followed by the
address low byte and then the address high byte the followed by the byte of data to be programmed.
NOTE
Individual bytes of address and data are transmitted LSB first. An 8-bit CRC of the
command byte, address bytes, and data byte is computed by the bq2024 and read back
by the host to confirm that the correct command word, starting address, and data byte
were received.
If the CRC read by the host is incorrect, a reset pulse must be issued and the entire sequence must be repeated.
If the CRC received by the host is correct, the program command (5Ah) is issued. After the program command is
issued, then the programming voltage, VPP is applied to the DATA pin for period tPROG. Prior to programming, the
first seven bytes of the EPROM STATUS data field appear as logical 1s. For each bit in the data byte provided
by the host that is set to a logical 0, the corresponding bit in the selected byte of the EPROM STATUS data field
is programmed to a logical 0 after the programming pulse has been applied at the byte location. The eighth byte
of the EPROM STATUS byte data field is factory-programmed to contain 00h.
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Write Status
Command?
(55h)
Selected
State
N
Selected
State
Y
bq2024 Receives Low Address Byte
(LSB First) AD0 to AD7
bq2024 Receives High Address Byte
(LSB First) AD8 to AD15
bq2024 Loads Address into Address Counter
bq2024 Receives 1 Byte of Data
and Stores in RAM Buffer
bq2024 Transmits CRC of Write Status
Command, Address, and Data
bq2024
Calculates and Transmits
CRC of Loaded Address and
Shifted Data
N
Code 5Ah
Received
Y
VDATA = VPP?
N
Y
Contents of RAM buffer AND’ed with contents of
data memory as pointed to by address counter .
Programming time required to be at least
t EPROG when VPP is applied to the data pin
bq2024
Receives Data Byte
bq2024
Increments Address
Counter and Loads
New Address into CRC
Register
bq2024
Transmits Data Byte of
Status Memory Pointed
to by Address Counter
End of Status
Memory?
N
Y
bq2024
Waits for Reset
Figure 11. WRITE STATUS Command Flow
12
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After the programming pulse is applied and the data line returns to VPU, the host issues eight read time slots to
verify that the appropriate bits have been programmed. The bq2024 responds with the data from the selected
EPROM STATUS address sent least significant bit first. This response should be checked to verify the
programmed byte. If the programmed byte is incorrect, then the host must reset the device and begin the write
sequence again. If the bq2024 EPROM data byte programming was successful, the bq2024 automatically
increments its address counter to select the next byte in the STATUS MEMORY data field. The least significant
byte of the new two-byte address is also loaded into the 8-bit CRC generator as a starting value. The host issues
the next byte of data using eight write time slots.
As the bq2024 receives this byte of data into the RAM buffer, it also shifts the data into the CRC generator that
has been preloaded with the LSB of the current address and the result is an 8-bit CRC of the new data byte and
the LSB of the new address. After supplying the data byte, the host reads this 8-bit CRC from the bq2024 with
eight read time slots to confirm that the address incremented properly and the data byte was received correctly.
If the CRC is incorrect, a Reset Pulse must be issued and the Write Status command sequence must be
restarted. If the CRC is correct, the host issues a programming pulse and the selected byte in memory is
programmed.
NOTE
The initial write of the WRITE STATUS command, generates an 8-bit CRC value that is
the result of shifting the command byte into the CRC generator, followed by the twoaddress bytes, and finally the data byte. Subsequent writes within this WRITE STATUS
command due to the bq2024 automatically incrementing its address counter generates an
8-bit CRC that is the result of loading (not shifting) the LSB of the new (incremented)
address into the CRC generator and then shifting in the new data byte.
For both of these cases, the decision to continue programming the EPROM Status registers is made entirely by
the host, because the bq2024 is not able to determine if the 8-bit CRC calculated by the host agrees with the 8bit CRC calculated by the bq2024. If an incorrect CRC is ignored and a program pulse is applied by the host,
incorrect programming could occur within the bq2024. Also note that the bq2024 always increments its internal
address counter after the receipt of the eight read time slots used to confirm the programming of the selected
EPROM byte. The decision to continue is again made entirely by the host, therefore if the EPROM data byte
does not match the supplied data byte but the master continues with the WRITE STATUS command, incorrect
programming could occur within the bq2024. The WRITE STATUS command sequence can be ended at any
point by issuing a reset pulse.
Table 3. Command Code Summary
COMMAND
(HEX)
DESCRIPTION
33h
Read Serialization ROM and
CRC
55h
Match Serialization ROM
F0h
Search Serialization ROM
CCh
Skip Serialization ROM
F0h
Read Memory/Field CRC
AAh
Read EPROM Status
C3h
Read Memory/Page CRC
0Fh
Write Memory
99h
Programming Profile
55h
Write EPROM Status
5Ah
Program Control
CATEGORY
ROM Commands Available in Command Level I
Memory Function Commands
Available in Command Level II
Program Command Available Only in WRITE
MEMORY and WRITE STATUS Modes
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PROGRAM PROFILE BYTE
The PROGRAM PROFILE byte is read to determine the WRITE MEMORY programming sequence required by a
specific manufacturer. After issuing a ROM command, the host issues the PROGRAM PROFILE BYTE
command, 99h. Figure 12 shows the the bq2024 responds with 55h. This informs the host that the WRITE
MEMORY programming sequence is the one described in the WRITE MEMORY command section of this data
sheet.
From ROM
Command
Program
Profile Command?
99h
N
Other
Command
Codes
Y
bq2024 Transmits
55h
bq2024
is in
Reset State
Master Issues Reset
Figure 12. PROGRAM PROFILE Command Flow
SDQ SIGNALING
All SDQ signaling begins with initializing the device, followed by the host driving the bus low to write a 1 or 0, or
to begin the start frame for a bit read. Figure 13 shows the initialization timing, whereas Figure 14 and Figure 15
show that the host initiates each bit by driving the DATA bus low for the start period, tWSTRB / tRSTRB. After the bit
is initiated, either the host continues controlling the bus during a WRITE, or the bq2024 responds during a
READ.
RESET AND PRESENCE PULSE
If the DATA bus is driven low for more than 120 μs, the bq2024 may be reset. Figure 13 shows that if the DATA
bus is driven low for more than 480 μs, the bq2024 resets and indicates that it is ready by responding with a
PRESENCE PULSE.
VPU
VIH
VIL
RESET
(Sent by Host)
t RST
Presence Pulse
(Sent by bq2024)
t PPD
t PP
t RSTREC
Figure 13. Reset Timing Diagram
WRITE
The WRITE bit timing diagram in Figure 14 shows that the host initiates the transmission by issuing the tWSTRB
portion of the bit and then either driving the DATA bus low for a WRITE 0, or releasing the DATA bus for a
WRITE 1.
14
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V PU
SLUS770 – MAY 2007
Write ”1”
V IH
V IL
Write ”0”
t rec
t WSTRB
t WDSU
t WDH
Figure 14. Write Bit Timing Diagram
READ
The READ bit timing diagram in Figure 15 shows that the host initiates the transmission of the bit by issuing the
tRSTRB portion of the bit. The bq2024 then responds by either driving the DATA bus low to transmit a READ 0 or
releasing the DATA bus to transmit a READ 1.
VPU
Read ”1”
V IH
V IL
Read ”0”
t RSTRB
t REC
t ODD
t ODHO
Figure 15. Read Bit Timing Diagram
PROGRAM PULSE
VPP
VPU
tPSU
tPFE
tPRE
tPREC
tEPROG
VSS
Figure 16. Program Pulse Timing Diagram
IDLE
If the bus is high, the bus is in the IDLE state. Bus transactions can be suspended by leaving the DATA bus in
IDLE. Bus transactions can resume at any time from the IDLE state.
CRC Generation
The bq2024 has an 8-bit CRC stored in the most significant byte of the 64-bit ROM. The bus master can
compute a CRC value from the first 56 bits of the 64-bit ROM and compare it to the value stored within the
bq2024 to determine if the ROM data has been received error-free by the bus master. The equivalent polynomial
function of this CRC is: X8 + X5 + X4 +1.
Under certain conditions, the bq2024 also generates an 8-bit CRC value using the same polynomial function just
shown and provides this value to the bus master to validate the transfer of command, address, and data bytes
from the bus master to the bq2024. The bq2024 computes an 8-bit CRC for the command, address, and data
bytes received for the WRITE MEMORY and the WRITE STATUS commands and then outputs this value to the
bus master to confirm proper transfer. Similarly, the bq2024 computes an 8-bit CRC for the command and
address bytes received from the bus master for the READ MEMORY, READ STATUS, and READ DATA/
GENERATE 8-BIT CRC commands to confirm that these bytes have been received correctly. The CRC
generator on the bq2024 is also used to provide verification of error-free data transfer as each page of data from
the 1536-bit EPROM is sent to the bus master during a READ DATA/GENERATE 8-BIT CRC command, and for
the eight bytes of information in the status memory field.
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In each case where a CRC is used for data transfer validation, the bus master must calculate a CRC value using
the polynomial function previously given and compare the calculated value to either the 8-bit CRC value stored in
the 64-bit ROM portion of the bq2024 (for ROM reads) or the 8-bit CRC value computed within the bq2024. The
comparison of CRC values and decision to continue with an operation are determined entirely by the bus master.
No circuitry on the bq2024 prevents a command sequence from proceeding if the CRC stored in or calculated by
the bq2024 does not match the value generated by the bus master. Proper use of the CRC can result in a
communication channel with a high level of integrity.
CLK
DAT
Q
D
R
Q
D
R
Q
D
R
Q
D
R
+
Q
D
+
R
Q
D
R
Q
D
R
Q
D
+
R
UDG-02065
Figure 17. 8-Bit CRC Generator Circuit (X8 + X5 + X4 + 1)
16
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PACKAGE OPTION ADDENDUM
www.ti.com
11-Jun-2013
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
Lead/Ball Finish
(2)
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
BQ2024DBZR
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
-20 to 70
CCAI
BQ2024DBZRG4
ACTIVE
SOT-23
DBZ
3
3000
Green (RoHS
& no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
-20 to 70
CCAI
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
(4)
There may be additional marking, which relates to the logo, the lot trace code information, or the environmental category on the device.
(5)
Multiple Device Markings will be inside parentheses. Only one Device Marking contained in parentheses and separated by a "~" will appear on a device. If a line is indented then it is a continuation
of the previous line and the two combined represent the entire Device Marking for that device.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
Samples
PACKAGE MATERIALS INFORMATION
www.ti.com
20-Jul-2010
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
BQ2024DBZR
Package Package Pins
Type Drawing
SPQ
SOT-23
3000
DBZ
3
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
179.0
8.4
Pack Materials-Page 1
3.15
B0
(mm)
K0
(mm)
P1
(mm)
2.95
1.22
4.0
W
Pin1
(mm) Quadrant
8.0
Q3
PACKAGE MATERIALS INFORMATION
www.ti.com
20-Jul-2010
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
BQ2024DBZR
SOT-23
DBZ
3
3000
203.0
203.0
35.0
Pack Materials-Page 2
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