80-000541 Critical Link

Critical Link, LLC RS232 Expansion Kit www.CriticalLink.com 5 March 2014 FEATURES Applications 1 RS-232 Compliant Output External Hardware Interfacing 1 RS-232 Compliant Input Embedded Instrumentation RS232 Protocol - Up to 115,200 baud rate On-Board TX/RX Output Swapping - Resistor changeable Compatible with MitySOM/MityDSP based Development Kits from Critical Link (1.8 x 1.2 actual size) DESCRIPTION The RS232 Expansion Kit is compatible with Critical Link s line of MitySOM/MityDSP based development kits one is required to interface with this expansion kit. All MitySOM/MityDSP based System on Modules support RS232, see Table 1 for details concerning SoM support. Table 1: Critical Link SoM RS232 Support Module Type RS232 Support MitySOM-1810 Yes MitySOM-1810F Yes MityDSP-L138 Yes MityDSP-L138F Yes MitySOM-1808 Yes MitySOM-1808F Yes MitySOM-3359 Yes 1 Copyright 2007-2012, Critical Link LLC Critical Link, LLC RS232 Expansion Kit www.CriticalLink.com 5 March 2014 RS232 Description The RS232 Expansion Kit provides standard serial interface at data rates up to 115,200 baud that can be seamlessly added to your design. The serial interface is routed to one of the UART ports of the MitySOM/MityDSP through the UART Expansion Header on a MitySOM/MityDSP based Development Kit. Linux Driver and API examples are available. The level conversion from the input CMOS levels to the output RS232 levels is done by a MAX3232IDR Line Driver/Receiver. This part offers two receivers and drivers but the second set is unused on this board. Through the use of 4 resistors the RS232 Expansion Kit can alter which output pins are used for TX and RX depending if a null-modem or standard cable type is necessary. See Table 4 for details. The electrical interface between the RS232 Expansion Kit and MitySOM/MityDSP based Development Kit is provided via the 10-pin shrouded header described in Table 2. The electrical interface between the RS232 Expansion Kit and an external device is provided via the 9-pin DB9 connector described in Table 3. Please reference your specific MitySOM/MityDSP Based Development Kit documentation to determine which connector to use for the RS232 Expansion Kit. 2 Copyright 2007-2012, Critical Link LLC