W S N 8 0 2 G
S P I M a s te r M o d e S ig n a lin g
S P I_ IN
S P I_ O U T
S la v e
S C L K
/S S
W S N 8 0 2 G
Figure 2.5.1
Figure 2.5.1 shows the signals a WSN802G uses in SPI Master mode. The AutoReport function triggers
the WSN802G module to clock out a configurable command string,
SPI_MasterCmdStr,
to collect data
from a Slave peripheral. The collected data is then transmitted as a data message. Alternatively, a host
connected to the base can transmit an SPI command as a data message to the remote. The WSN802G
will clock the command into its Slave peripheral and transmit back the Slave’s response, as show in Fig-
ure 2.5.2. In either case, data strings are limited to 256 bytes.
W S N 8 0 2 G
/S S
S P I M a s te r M o d e O p e r a tio n
S C L K
S P I B it C lo c k
S P I_ O U T
D a ta /D a ta g r a m
to S la v e
S P I_ IN
D a ta /D a ta g r a m
fro m
S la v e
Figure 2.5.2
2.6 Analog I/O
The WSN802G includes two 10-bit ADC inputs, ADC0 (Pin 18) and ADC1 (Pin 19). Pin 25 provides a full-
scale reference voltage to support ratiometric ADC measurements. ADC measurements are triggered and
added to the automatic I/O report when a logic high signal is first applied to the WAKE_ IN pin or the
AutoReport
timer fires, as discussed in Section 2.2. An ADC reading is also made on the internal buss
voltage of the WSN802G and included in the automatic I/O report. These readings can also be retrieved
anytime the WSN802G is in active mode using the IO_REPORT application protocol command as dis-
cussed in Section 4.1.
The WSN802G also includes a 16-bit pulse width modulated output, PWM0 (Pin 9). The PWM output is
low-pass filtered to provide an analog output voltage with ripple suppressed to 7 bits. External low-pass
filtering can be added to further suppress ripple. The full-scale PWM output is referenced to the regulated
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