USB Interface
Experimenting with the Universal Serial Bus
Published in issue 291, September 2000
Everybody is talking about the USB. In the long term, this new serial interface could replace many of the PC interfaces that have been used up to now. This is reason enough for looking at it more closely.Before getting into practical details, let’s first look at the basic features of the Universal Serial Bus. In USB Version 1.0, there are ‘lowspeed’ devices with a data rate of 1.5 Mb/s, and ‘fullspeed’ devices with a data rate of 12 Mb/s. Even the lower data transfer rate is several times faster than the possible baud rates of a serial interface.Up to now, we have often been faced with unpleasant situations in which all of the PC interfaces are already in use. The advantage of the USB here is that you can always make four new ports available by connecting a supplementary bus distributor (hub). Up to 127 devices in total can be connected to the bus.
Resistors:
R1 = 47Ω
R2 = 270Ω
R3 = 10kΩ
R4 = 47Ω
R5 = 1kΩ5
Capacitors:
C1,C2 = 100nF
Semiconductors:
D1 = LED, red,
D2 = LED, green
IC1 = CY7C63001ACP (programmed, order code 000079-41)
IC2 = DS1620
Miscellaneous:
JP1,JP2 = 2-way pinheader with
jumper
K1 = 10-way PCB terminal block
K2 = solder pin
K3 = USB socket, PCB mount, type B (Farnell #153-503)
S1 = pushbutton 1 make contact
X1 = 6MHz ceramic resonator, (Murata CSA6.00MG (Farnell # 295-292), or Newport ZTA6.00MT
Enclosure: approx. size 61x22x80 mm (Conrad Electronics #522848)
Project disk, order code 000079-11
PCB, order code 000079-1
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Click below to download a PDF copy of this article from Elektor magazine. Please note. In view of the complexity of international markets, Elektor cannot guarantee the availability of components for this project.
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