BQ2026 Datasheet, PDF (7/22 Pages) Texas Instruments – 1.5K-Bit Serial EPROM With SDQ Interface

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bq2026
SLUS938 – DECEMBER 2011
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 16-bit CRC of the command byte and address bytes is computed by the bq2026 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 bq2026
starting at the supplied address and continuing until the end of the EPROM Status data field is reached. At that
point, the host receives a 16-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 byte.
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 a 16-bit CRC that is based on (and always is consistent with) the current data stored in the
EPROM status data field.
After the 16-bit CRC is read, the host receives logical 1s from the bq2026 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
CommandSequence
READ MEMORY
Command
AAh
Address Low
Byte
Address High
Byte
Read STATUS Memory Until
End of Page
A0
A7 A8
A15
Figure 7. READ STATUS Command
Read and
Verify 16-bit
CRC
of command,
address and
data
Copyright © 2011, Texas Instruments Incorporated
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