Questions tagged [ttl]
Transistor Transistor Logic. Logic circuits built from bipolar transistors and resistors.
60
questions with no upvoted or accepted answers
1
vote
0
answers
73
views
Issues using a 74LS245 with Attiny85
I have a Raspberry Pi, a 74LS245, and an ATTiny85.
I connected the Pi to the Tiny through 1k resistors, and am able to use SPI to program it, no problem.
I have added a 74LS245 inbetween, to ...
1
vote
0
answers
239
views
XOR Gate implemented with BC547 transistors not working
I have checked and rechecked the wiring on my breadboard against the circuit shown in the schematic a dozen times and can't for the life of me understand why it is not working. Can anyone see a fault ...
- 121
1
vote
2
answers
598
views
HC-SR04 distance sensor trigger signal on 2.5 V voltage level gives no reading
I am using an Arduino on a breadboard setup with an ATMEGA328p MCU. The whole circuit is designed to work in a low-power state and is powered using a 3 V (nominal) Coin Cell.
The HC-SR04 is getting a ...
- 131
1
vote
0
answers
670
views
RS-232 Level Shifter
Most PCs don't have RS232 built-in anymore. So the only option is USB-2-RS232 adapters or RS232 PCI-E card. While I expected the adapters to output a low voltage it turns out most RS232 PCI-E card ...
- 11
1
vote
0
answers
371
views
CP2108 with level converter txb0108 - UART communication TTL and LVTTL
My project uses four different modems (one 3v3 LVTTL(?) and three 5v TTL) for AT communication.
Each modem has a UART interface (TTL compatible).
For my application, i chose the CP2108 to ...
- 11
1
vote
0
answers
257
views
Composite video out from 74AHCxx gates with 16MHz clock. Insane?
just for fun and while waiting for other components to arrive I want to build a composite video out from available hardware. So please no suggestions to just by a propeller.
Available hardware:
...
0
votes
0
answers
46
views
Counting up/shifting right, counting down/shifting left 4164 DRAM addresses using TTL/CMOS
I'm working on a design that uses 4164 (64kb x 1 bit) DRAM with 8 addresses (0-7), and I would like to be able to utilize a TTL/CMOS counter or shift register to make the data output count down/go in ...
0
votes
0
answers
26
views
Why would I use HNM (high noise margin) gate drive over a TTL gate drive for DC motor driving application?
I am making a very simple half bridge DC motor drive using the MAX1760 gate driver. Looking through the datasheet I saw that it offers two types of logic level technologies (if that's the right word?);...
- 229
0
votes
0
answers
59
views
What is the quiescent power dissipated by a TTL totem-pole output stage?
In High-Speed Digital Design by Johnson and Graham, the quiescent power of a TTL totem-pole is given as:
$$P_{quies} = \frac{0.4I_{sink} + 1.0I_{source}}{2}$$
I am fairly certain the 1.0 is a mistake ...
- 209
0
votes
0
answers
146
views
Bare esp32 chip auto programming mode help
So I'm very much a newbie when it comes to using bare chips but since I'm trying to make a project which requires very small modules for wifi I'm stuck using a bare one. My question would be how to ...
0
votes
0
answers
86
views
J-K flip-flops TTL to CMOS
The following uses 3 TTL 74SLS76N J-K flip-flops, which are active low:
However, I'm trying to figure out what the settings for the PR and CLR inputs would be using CMOS CD4027 J-K flip-flops. For ...
- 57
0
votes
0
answers
158
views
Understanding cascasing of 74185
The 74185 is a binary-to-BCD converter. It is designed cleverly utilizing the fact that both 10 and 2^n are divisible by 2 once, thereby omitting processing of the LSB entirely. More interestingly ...
0
votes
0
answers
285
views
ESP32-C3-WROOM: error flashing chip
I am developing an ESP32-C3-WROOM custom board, but when I tried to flash the chip using UART (FT232D USB-TTL) and Arduino IDE, I got the message "A fatal error occurred: Failed to connect to ...
0
votes
0
answers
149
views
Could I have a whole batch of bad AT26C16 EEPROM chips?
I am in TTL chip heaven (India) where I can get these things for pennies on the dollar, so I bought batches of chips to tinker with. Among them a 16 AT28C16 EEPROMs, looking like new, and then 2 very ...
- 1,541
0
votes
0
answers
494
views
FT232RL Chip is not working (USB to TTL)
I used an FT232RL chip to make a USB to TTL converter using the schematic below.
Although I can send a message and the TX LED is lightining up, I cannot receive any messages.
Can anyone see a problem ...
- 19