28129 Parallax Inc, 28129 Datasheet - Page 43

• Manufacturer Part Number: 28129
• Description: TEXT BASIC ANALOG & DIGITAL
• Manufacturer: Parallax Inc
• Type: Programmingr

Specifications of 28129

• Style: Book
• Title: Basic Analog and Digital
• Contents: Basic Analog and Digital Text
• Product: Microcontroller Accessories
• Lead Free Status / RoHS Status: Not applicable / Not applicable

Press and hold the right button, then press and release the left button twice. Then the
output should look like Figure 2-7.
If your program worked as shown, you just synchronously shifted 4 serial bits into the
BASIC Stamp's RAM. In addition, it was verified that the decimal value of binary-1011
really is 11 in the decimal number system.
Figure 2-8 shows how these events occurred (from left to right) in a timing diagram. The
left pushbutton was the clock signal. The clock signal consisted of a series of clock
pulses. Each clock pulse was the press and release of the left pushbutton. This sent a low-
high-low signal to P1. Each time the left pushbutton was released, the BASIC Stamp
checked the state of the data line, which was the state of the right pushbutton (P0). The
BASIC Stamp is programmed to read the input data after the clock signal's transition
from high to low. This transition is referred to as the negative edge of the clock pulse.
Figure 2-7
Debug Terminal
Output for Program
Listing 2.2.