BQ2026 Datasheet, PDF (9/22 Pages) Texas Instruments – 1.5K-Bit Serial EPROM With SDQ Interface

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bq2026
SLUS938 – DECEMBER 2011
WRITE MEMORY
The WRITE MEMORY command is used to program the 1536-bit EPROM memory field. The 1536-bit memory
field is programmed in 1-byte segments. Data is first written into an 1-byte RAM buffer. 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 host then transmits 1 byte of data to the bq2026.
a 16-bit CRC is calculated and transmitted based on the command, address and data. If this CRC agrees with
the CRC calculated by the host, the host applies the programming voltage for at least 480 μs or t_EPROG.
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.
The WRITE DATA MEMORY command sequence can be terminated at any point by issuing a reset pulse except
during the program pulse period t_PROG.
NOTE
The bq2026 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.
For both of these cases, the decision to continue programming is made entirely by the host, because the bq2026
is not able to determine if the 16-bit CRC calculated by the host agrees with the 16-bit CRC calculated by the
bq2026.
Prior to programming, bits in the 1536-bit EPROM data field appear as logical 1s.
Copyright © 2011, Texas Instruments Incorporated
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