A how-to on making a DIY RS232 to TTL converter by Jestine Yong: As I read many pages on the internet I saw there is a sort of adapter so called “USB to TTL adapter” who can communicate through with the uC. I had not the time to order one but I give a try […]
Tag Archives: TTL
TTL triggered stimulus generator
Scott Harden has a nice build log on his TTL triggered stimulus generator project: I was presented with a need to rapidly develop a pulse generator to take a TTL input and output a programmable output (for now 0.1 ms pulses at 20 Hz for as long as the input is high). I achieved this […]
Inside the 74181 ALU chip: die photos and reverse engineering
A detailed die photos and reverse engineering of the 74181 ALU chip by Ken Shirriff: What’s inside a TTL chip? To find out, I opened up a 74181 ALU chip, took high-resolution die photos, and reverse-engineered the chip.1 Inside I found several types of gates, implemented with interesting circuitry and unusual transistors. The 74181 was a […]
I2C controled 8 relay driver switches plug-in devices
Megabug posted his I2C relay driver board for controlling 8 outputs. It controls 8 relay switches in which one pin of each switch is common, while the other pins are available through 8 screw type headers. It uses the PCA9554 8bit I2C port expander to drive a ULN2803A buffer which in return drives the relay coils. All buffer input […]
1988 TTL logic data book
Daniel Brake writes: I don’t know if you guys have seen this yet, but TI has their 1988 TTL Logic Data Book for only $0.10. I have received 3 copies and the total cost, including shipping (US), was only $0.30! TI describes this book as: Texas Instruments presents pertinent technical information on their broad line […]