DS1670 Datasheet, PDF (10/16 Pages) Dallas Semiconductor – Portable System Controller

DS1670
Address and data bytes are always shifted LSB first into the I/O pin. Any transaction requires the
address/command byte to specify a read or write to a specific register followed by one or more bytes of
data. The address byte is always the first byte entered after CS is driven high. The most significant bit
( RD /WR) of this byte determines if a read or write will take place. If this bit is 0, one or more read cycles
will occur. If this bit is 1, one or more write cycles will occur.
Data transfers can occur 1 byte at a time or in multiple-byte burst mode. After CS is driven high an
address is written to the DS1670. After the address, one or more data bytes can be read or written. For a
single-byte transfer 1 byte is read or written and then CS is driven low. For a multiple-byte transfer,
multiple bytes can be read or written to the DS1670 after the address has been written. Each read or write
cycle causes the register address to automatically increment. Incrementing continues until the device is
disabled. After accessing register 0Eh, the address wraps to 00h.
Data transfer for single-byte transfer and multiple-byte burst transfer is illustrated in Figures 7 and 8.
SINGLE-BYTE DATA TRANSFER Figure 7
CS
SCLK
A0 A1 A2 A3 A4
A5
A6
RD
WR
D0
D1
D2
D3 D4 D5 D6 D7
MULTIPLE-BYTE BURST TRANSFER Figure 8
CS
SCLK
I/O
ADDRESS
DATA
BYTE
BYTE 0
DATA
BYTE 1
DATA
BYTE N
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