Mar 24
USBtoparallel
This device was built using AVRUSB firmware developed by extern Objective Development.
Meanwhile, a very similar Release 1.6 exists.
This Low-Speed device violates following USB specification rules:
* Detachable cable (must be captive for Low-Speed)
* Output drivers with 5 V (must be 3.3 V, but USB is 5 V tolerant)
* No differential data input (only one line D- is sampled)
* No data clock regenration while receiving (only at packet start)
* No error detection of input data (OUT direction), no time for CRC16
* Data transfer using BULK pipes (not specified for low-speed, but works on Windows – for Linux there is an “Alternate Setting” with INTERRUPT pipes instead)
However, new to this firmware, following rules are accepted:
* Suspend detection and lowered suspend current (below 500 µA)
[Via]
Mar 23
The Universal Serial Bus (USB) interface has become extremely popular, due to its simplicity for end user applications (Plug and Play without restart). For developers, however, USB implementation into end systems has been more complicated compared to e.g. RS232. In addition there is a need for device drivers as software support on the PC side. Because of this, RS232 based communication is still very popular among end systems manufacturers. This interface is well established and has good operating system support, but recently the physical RS232 port has been removed from the standard PC interface, giving ground to USB ports. Implementation of USB into external devices can be done in two ways:
1. By using a microcontroller with hardware implemented USB interface. It is necessary to know how USB works and write firmware into the microcontroller accordingly. Additionally, it is necessary to create a driver on the computer side, unless if the operating system includes standard USB classes. The main disadvantage is the lack of availability of this kind of microcontrollers and their high price compared to simple “RS232” microcontrollers.
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Mar 11
I have done a simple infrared remote control receiver with RS232 ascii output. It can be used for developing remote controls on a PC using the serial port. In practice, the infrared bursts are converted in ascii characters and sent to the RS232 port. The downloadable ZIP file contains the schematic diagram, the printed circuit board, the components disposition and the object file to write into the ATMEL ATtiny2313 microcontroller.
Link [Via]
Dec 25
Serial RS232 to USB
This is simple RS232 Serial to USB Converter that doesn’t need any further explanations. You can use it for any projects that might need it.
link
