BQ2026 Datasheet, PDF (5/22 Pages) Texas Instruments – 1.5K-Bit Serial EPROM With SDQ Interface

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ROM COMMANDS
bq2026
SLUS938 – DECEMBER 2011
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. The READ ROM sequence starts with the host generating the RESET pulse of
at least 480 μs. The bq2026 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
Read ROM (33h)
Signals 1 1 0 0 1 1 0 ⁰
Family Code and Identification
Number (7 BYTES)
CRC (1 BYTE)
Figure 3. READ ROM Sequence
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. 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)
0 10 10
10
Family Code and Identification
Number (7 BYTES)
CRC (1 BYTE)
Figure 4. MATCH ROM Sequence
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.
Reset
and
Skip ROM (CCh)
Presence
0
1
0
1
0
1
0
1
Signals
Figure 5. SKIP ROM Sequence
Copyright © 2011, Texas Instruments Incorporated
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