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List of ideas for getting started with TimVideos projects
https://code.timvideos.us/summer-of-code/
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[HDMI2USB] Create a serial port extension board - Support both RS232 and RS485 modes. #10

Open mithro opened 11 years ago

mithro commented 11 years ago

Brief explanation

Create a serial port extension board - Support both RS232 and RS485 modes

Should also have lots of blinking lights.

Firmware should be modified so that they appear as USB-CDC ports to the computer.

Detailed Explanation

This can be achieved using SP331 transceiver.

The SP331 is a programmable RS-232 and/or RS-485 transceiver IC. The SP331 contains four drivers and four receivers when selected in RS-232 mode; and two drivers and two receivers when selected in RS-485 mode. The SP331 also contains a dual mode which has two RS-232 drivers/receivers plus one differential RS-485 driver/receiver.

The RS-232 transceivers can typically operate at 230kbps while adhering to the RS-232 specifications. The RS-485 transceivers can operate up to 10Mbps while adhering to the RS-485 specifications. The SP331 includes a self-test loopback mode where the driver outputs are internally configured to the receiver inputs. This allows for easy diagnostic serial port testing without using an external loopback plug. The RS-232 and RS-485 drivers can be disabled (High-Z output) by controlling a set of four select pins.

Further reading

sidoknowia commented 11 years ago

This can be achieved using SP331 transcevier. The SP331 is a programmable RS-232 and/or RS-485 transceiver IC. The SP331 contains four drivers and four receivers when selected in RS-232 mode; and two drivers and two receivers when selected in RS-485 mode. The SP331 also contains a dual mode which has two RS-232 drivers/receivers plus one differential RS-485 driver/receiver. The RS-232 transceivers can typically operate at 230kbps while adhering to the RS-232 specifications. The RS-485 transceivers can operate up to 10Mbps while adhering to the RS-485 specifications. The SP331 includes a self-test loopback mode where the driver outputs are internally configured to the receiver inputs. This allows for easy diagnostic serial port testing without using an external loopback plug. The RS-232 and RS-485 drivers can be disabled (High-Z output) by controlling a set of four select pins.

mithro commented 10 years ago

A lot of care should be taken in figuring out the correct connectors for http://www.zytrax.com/tech/layer_1/cables/tech_rs232.htm

RS-485/RS422 should probably end up on RJ45 style connectors. RS232 should end up on good old DB9 connectors.

mithro commented 10 years ago

Two Linux Kernel Drivers which support multiple serial ports on a single endpoint are;

mithro commented 10 years ago

Example designs from previous student;

image

copy of gsoc proposal by ayush3504