TTL：生存时间，主要用于三层数据的防环，TTL在IPv4包头中携带，共8个bit位，最大值255，每经过一个三层设备就减一，为零后丢弃该数据包。

Point of terminology: "TTL serial" is a severely over-broad term, " (point-to-point) asynchronous serial (at TTL levels)" seems to be what you're asking about. (Though that's still probably …

Jun 22, 2023 · TTL requires that logic 1 input must be at least 2V, and TTL drivers are designed to guarantee that. That is far short of what this driver requires to register as logic 1.

Aug 14, 2012 · TTL mean Transistor-Transistor-Logic and has its level for logical zero near 0V and for logical one near 5V. Often any 5V logic is called TTL, although most circuits nowadays …

Feb 18, 2023 · I need to implement a TTL to RS485 converter into an home made project and searching by Google I found this module with related schematics: Could you help me by …

Feb 25, 2025 · Unsurprisingly, since we know that TTL pull-down needs to sink current from the input while a pull-up doesn't, the required TTL pull-down resistor value is smaller than the pull …

Mar 8, 2024 · 此外，增量编码器的信号输出电平标准也是多样的，常见的有TTL、HTL、PNP和NPN等。 TTL和HTL是常见的电平标准，其中TTL为长线差分驱动，而HTL也称为推拉式或推 …

Mar 10, 2018 · I've been having some issues lately with the usage of 10k ohm resistors as pull down resistors for 74ls series chips. Most people seem to choose 10k resistors as their default …

Sep 11, 2020 · I keep coming back here searching for an RC-based negative edge detector for TTL levels, that generates a negative pulse on a falling edge. The only place I find this solution …

TTL integrated circuits assume unconnected inputs to be at logic 1 because the main requirement for driving a TTL input is to pull-down the level to near 0 V which takes about 1 mA per input. …