70009 Parallax Inc, 70009 Datasheet - Page 76

• Manufacturer Part Number: 70009
• Description: BOOK UNDERSTANDING SIGNALS
• Manufacturer: Parallax Inc
• Type: Signal Analysisr

Specifications of 70009

• Style: Book
• Title: Understanding Signals
• Contents: Guide to Generate, View and Measure Wave Forms
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable
• Other names: 70009PAR

' -----[ Subroutines ]-----------------------------------------------------
ADC_Data:
RETURN
Display:
RETURN
The blue signal at the bottom is the data signal. The data signal is what communicates a
“1” or “0” to the device you are trying to talk to. A “1” is detected when the signal is
above the TTL threshold, a “0” when the signal is below the TTL threshold.
The red signal on top is the clock. The clock tells the device you are talking to when to
sample the data signal. This happens on the rising edge of the clock signal. At that instant
in time the receiving device will look at the data line and latch in that value, a “1” or a
“0”. That explains why this is synchronous serial communication; the master (the BASIC
Stamp) and the slave (the ADC0831) agree to send and receive data according to the state
of a second signal, the clock.
HIGH CS
LOW CS
LOW CLK
PULSOUT CLK, 210
SHIFTIN DataOutput,CLK,MSBPOST,[adcBits\8]
DEBUG HOME
DEBUG "8-bit binary value:
DEBUG CR, CR, "Decimal Value: ", DEC3 adcBits
√
√
√
√
Use the red and blue arrows to separate the two signals in the display, as shown
in Figure 5-5.
Next, put your BASIC Stamp Debug Terminal side by side with your
OPTAscope display to see the values you are receiving from the OPTAscope.
Adjust the potentiometer tap by gently twisting the knob until the Debug
Terminal Decimal Value reads 080. Your signals should now look like those in
Figure 5-5.
If you do not get a similar signal, make sure your Trigger Mode switch is set to
Normal. Also, you may need to slide your Plot Area Indicator bar to the right to find
the whole signal.
Clock Line vs. Data Line: The BASIC Stamp controls the clock line, but it is the ADC0831
that controls the data line
", BIN8 adcBits