MAX15501EVKIT+ Maxim Integrated Products, MAX15501EVKIT+ Datasheet - Page 21

• Manufacturer Part Number: MAX15501EVKIT+
• Description: KIT EVAL FOR MAX15501
• Manufacturer: Maxim Integrated Products

Specifications of MAX15501EVKIT+

• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The MAX15500/MAX15501 relinquish control of DOUT
once the devices process the frame(s). DOUT remains
high impedance when the SPI interface continues to hold
CS_ low beyond the required frame(s). Install a pullup/
puldown resistor at the DOUT line to maintain the desired
state when DOUT goes high impedance.
Single Device SPI Connection
For applications using a single MAX15500 or MAX15501,
connect both CS1 and CS2 inputs to the device-select
driver of the host microcontroller. Alternatively, connect
one of the CS_ inputs to the device-select driver of the
host microcontroller and the other CS_ to DGND. Both
methods allow standard SPI interface operation. See
Figures 3 and 4.
Daisy-Chain SPI Connection
The MAX15500/MAX15501-modified SPI interface allows
a single SPI master to drive multiple devices in a daisy-
chained configuration, saving additional SPI channels for
other devices and saving cost in isolated applications.
Figure 5 shows multiple MAX15500/MAX15501 devices
connected in a daisy chain. The chain behaves as a
single device to the microcontroller in terms of timing
with an expanded instruction frame requiring 16 SCLK
cycles per device for complete programming. No timing
parameters are affected by the READY propagation as
all devices connect to the microcontroller chip-select
through the CS1 inputs.
A chain of MAX15500/MAX15501 devices can be termi-
nated with any standard SPI-compatible single device
without a READY output. The MAX15500/MAX15501 por-
tion of the chain continues to display timing parameters
comparable to a single device. See Figure 6.
When using the MAX15500/MAX15501 with mixed
chains, the connections could require some modification
to accommodate the interfaces of the additional devices
in the chain. Construct the daisy chain as shown in
Figure 7 when using devices with similar READY outputs
but without dual CS_ inputs such as the MAX5134 quad
16-bit DAC. The chain is subject to timing relaxation for
parameters given with respect to CS_ rising edges to
accommodate READY propagation to and through con-
secutive MAX5134 devices.
The chain can begin and terminate with either device
type. Each MAX5134 or MAX15500/MAX15501 device
in the chain could be replaced by a subchain of similar
devices. If the chain is terminated with a standard SPI
device, omit the optional connection from READY to the
______________________________________________________________________________________
Voltage-Output Conditioners
Industrial Analog Current/
monitor input on the microcontroller. The MAX15500/
MAX15501 portion of the chain continues to display tim-
ing parameters comparable to a single device.
Figures 8, 9, and 10 show the operation of the modified
SPI interface. The minimum programming operation
typically used in single device applications is 16 SCLK
periods, the minimum for a valid frame. This cycle can
also represent the operation of the final device in a chain.
The extended programming operation is typically used
for devices in daisy-chained applications. In this case,
READY drives the chip-select input of the subsequent
device in the chain. The next device in the chain
begins its active frame on the 16th SCLK falling edge in
response to READY falling (latching DIN[13] on the 17th
SCLK falling edge, if present).
Aborted SPI Operations
Driving a CS_ input high before a valid SPI frame is
transmitted to the device can cause an erroneous com-
mand. Avoid driving CS_ high before a valid SPI frame is
transmitted to the device. See Figures 9 and 10 for valid
SPI operation timing.
Input data bits DIN[13:11] represent the SPI command
address while DIN[9:0] represent the data written to
or read from the command address. The command
address directs subsequent input data to the proper
internal register for setting up the behavior of the device
and selects the correct status data for readback through
DOUT. Command address 0h points to a no-op com-
mand and does not impact the operation of the device.
DOUT is active during this operation and reads back
00h. Command address 1h points to the configuration
register used to program the MAX15500/MAX15501.
Device configuration takes effect following the 14th
SCLK falling edge. DOUT activates and remains low dur-
ing this operation. Command addresses 4h and 5h point
to readback commands of the MAX15500/MAX15501.
Readback commands provide configuration and error
register status through DOUT[9:0] and do not affect the
internal operation of the device. Command addresses
2h, 3h, 6h, and 7h are reserved for future use. Table 5
shows the list of commands.
Table 6 shows the function of each bit written to the con-
figuration register 1h. Table 7 shows the data readback
registers.
SPI Digital Specifications and Waveforms
Device Configuration Operation
SPI Operation Definitions
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