KAD5512HP_14 Datasheet, PDF (24/34 Pages) Intersil Corporation – High Performance 12-Bit, 250/210/170/125MSPS ADC

KAD5512HP
Multiple slave devices can interface to a single master in
three-wire mode only, since the SDO output of an
unaddressed device is asserted in four wire mode.
The chip-select bar (CSB) pin determines when a slave
device is being addressed. Multiple slave devices can be
written to concurrently, but only one slave device can be
read from at a given time (again, only in three-wire mode). If
multiple slave devices are selected for reading at the same
time, the results will be indeterminate.
The communication protocol begins with an
instruction/address phase. The first rising SCLK edge
following a high-to-low transition on CSB determines the
beginning of the two-byte instruction/address command;
SCLK must be static low before the CSB transition. Data can
be presented in MSB-first order or LSB-first order. The
default is MSB-first, but this can be changed by setting
0x00[6] high. Figures 33 and 34 show the appropriate bit
ordering for the MSB-first and LSB-first modes, respectively.
In MSB-first mode the address is incremented for multi-byte
transfers, while in LSB-first mode it’s decremented.
In the default mode the MSB is R/W, which determines if the
data is to be read (active high) or written. The next two bits,
W1 and W0, determine the number of data bytes to be read
or written (see Table 6). The lower 13 bits contain the first
address for the data transfer. This relationship is illustrated in
Figure 35, and timing values are given in “Switching
Specifications” on page 8.
After the instruction/address bytes have been read, the
appropriate number of data bytes are written to or read from
the ADC (based on the R/W bit status). The data transfer will
continue as long as CSB remains low and SCLK is active.
Stalling of the CSB pin is allowed at any byte boundary
(instruction/address or data) if the number of bytes being
transferred is three or less. For transfers of four bytes or
more, CSB is allowed stall in the middle of the
instruction/address bytes or before the first data byte. If CSB
transitions to a high state after that point the state machine
will reset and terminate the data transfer.
TABLE 6. BYTE TRANSFER SELECTION
[W1:W0]
BYTES TRANSFERRED
00
1
01
2
10
3
11
4 or more
Figures 37 and 38 illustrate the timing relationships for
2-byte and N-byte transfers, respectively. The operation for a
3-byte transfer can be inferred from these diagrams.
SPI Configuration
ADDRESS 0X00: CHIP_PORT_CONFIG
Bit ordering and SPI reset are controlled by this register. Bit
order can be selected as MSB to LSB (MSB first) or LSB to
MSB (LSB first) to accommodate various microcontrollers.
Bit 7 SDO Active
Bit 6 LSB First
Setting this bit high configures the SPI to interpret serial
data as arriving in LSB to MSB order.
Bit 5 Soft Reset
Setting this bit high resets all SPI registers to default
values.
Bit 4 Reserved
This bit should always be set high.
Bits 3:0 These bits should always mirror bits 4:7 to avoid
ambiguity in bit ordering.
ADDRESS 0X02: BURST_END
If a series of sequential registers are to be set, burst mode
can improve throughput by eliminating redundant
addressing. In 3-wire SPI mode the burst is ended by pulling
the CSB pin high. If the device is operated in 2-wire mode
the CSB pin is not available. In that case, setting the
burst_end address determines the end of the transfer.
During a write operation, the user must be cautious to
transmit the correct number of bytes based on the starting
and ending addresses.
Bits 7:0 Burst End Address
This register value determines the ending address of the
burst data.
Device Information
ADDRESS 0X08: CHIP_ID
ADDRESS 0X09: CHIP_VERSION
The generic die identifier and a revision number,
respectively, can be read from these two registers.
Indexed Device Configuration/Control
ADDRESS 0X10: DEVICE_INDEX_A
A common SPI map, which can accommodate
single-channel or multi-channel devices, is used for all
Intersil ADC products. Certain configuration commands
(identified as Indexed in the SPI map) can be executed on a
per-converter basis. This register determines which
converter is being addressed for an Indexed command. It is
important to note that only a single converter can be
addressed at a time.
This register defaults to 00h, indicating that no ADC is
addressed. Error code ‘AD’ is returned if any indexed
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FN6808.3
October 1, 2009