- on Microcontrollers
- Published in issue 7/2010 on page 98
USB/TTL Serial Cable: Extension & Supplement
(Summer Circuits 2010 article)
Two years ago, I presented here the USB/TTL serial conversion cables from FTDI — wonderful communication and debugging tools. The increasingly frequent use of ARM CPUs has led us to use the 3.3 V version in order to protect the ARM’s input/output ports intended for 3.3 V (unless otherwise stated; the data sheets are unclear about this... but better safe than sorry!)
From now on, the 3.3 V version of the USB TTL-232R cable will be available in the Elektor online shop with the reference 080213-92. The 5 V version is still available with the reference 080213-91.
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CAM/CAD data for the PCB referred to in this article is available as a Gerber file. Elektor Members can exclusively download these files for free as part of their Membership. Gerber files allow a PCB to be produced on an appropriate device available locally, or through an online PCB manufacturing service. Elektor recommends its business partner Eurocircuits as the company of choice for its own prototypes and volume production in selected cases.
R1 = 10 kOhm
Capacitors (SMD 0805)
C1 = 100nF
IC1 = 74HCT4066 SMD version (e.g. Texas Instruments CD74HCT4066M)
S1 = 5-way DIP switch
S2 = pushbutton
K1 = 6-pin pinheader, right angled, lead pitch 0.1 inch (2.54mm)
K2 = 6-pin socket strip, right angled, lead pitch 0.1 inch (2.54mm)
K3,K4 = 6-pin pinheader, straight, lead pitch 0.1 inch (2.54mm)
K4, K6 = FASTON IC connector