19-6338; Rev 0; 5/12 MAX14840PMB1 Peripheral Module General Description The MAX14840PMB1 peripheral module provides the necessary hardware to interface the MAX14840E RS-485 transceiver to any system that utilizes PmodTM-compatible expansion ports configurable for a UART interface. The IC is a +3.3V ESD-protected transceiver intended for half-duplex RS-485 communication up to 40Mbps*. These transceivers are optimized for high speeds over extended cable runs, while maximizing tolerance to noise. The IC features symmetrical fail-safe and larger receiver hysteresis, providing improved noise rejection and improved recovered signals in high-speed and longcable applications. Features S Half-Duplex RS-485 Transceivers S 40Mbps Maximum Data Rate S Large (170mV) Receiver Hysteresis S Symmetrical Fail-Safe Receiver Input S Hot-Swap Capability S Short-Circuit-Protected Outputs S Thermal Self-Protection S Extended ESD Protection for RS-485 I/O Pins S 6-Pin Pmod-Compatible Connector (Pmod Interface Type 4 UART) *The maximum communication speed of this module is generally less than 10Mbps due to the presence of current-limiting resistors on the data lines of this module and possibly also the host board. S Example Software Written in C for Portability Refer to the MAX14840E IC data sheet for detailed information regarding operation of the IC. S Fully Assembled and Tested S RoHS Compliant S Proven PCB Layout Ordering Information appears at end of data sheet. MAX14840PMB1 Peripheral Module Pmod is a trademark of Digilent Inc. __________________________________________________________________ Maxim Integrated Products 1 For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com. MAX14840PMB1 Peripheral Module Component List DESIGNATION C1 QTY DESCRIPTION DESIGNATION QTY JP1 1 2-pin straight male header R1–R4 4 150I Q5% resistors (0603) R5 1 120I Q5% resistor (1206) 1FF Q10%, 10V X7R ceramic capacitor (0603) TDK C1608X7R1A105K 1 DESCRIPTION C2 1 0.1FF Q10%, 16V X7R ceramic capacitor (0603) Murata GRM188R71C104KA01D U1 1 40Mbps, +3.3V, RS-485 halfduplex transceiver (8 SO) Maxim MAX14840EASA+ J1 1 6-pin right-angle male header — 1 Shorting jumper 2-position terminal block On-Shore Technology ED500/2DS — 1 PCB: EPCB14840EPM1 J2 1 Component Suppliers SUPPLIER PHONE WEBSITE Murata Electronics North America, Inc. 770-436-1300 www.murata-northamerica.com On-Shore Technology, Inc. 480-921-3000 www.on-shore.com TDK Corp. 847-803-6100 www.component.tdk.com Note: Indicate that you are using the MAX14840PMB1 when contacting these component suppliers. Detailed Description UART Interface Table 1. Connector J1 (UART Communication) PIN SIGNAL DESCRIPTION The MAX14840PMB1 peripheral module can interface to the host by plugging directly into a Pmod-compatible port (configured for UART ) through connector J1. 1 RE Receiver-enable input. This active-low pin enables the half-duplex receiver. Connector J1 provides connection of the module to the Pmod host through an interface similar to the Pmod UART Type 4 standard recommended by Digilent. The transmit driver and receive pin assignment are the same as the standard. However, the CTS and RTS signals are replaced by half-duplex driver- and receiver-enable signals. See Table 1. 2 DI Driver input. This pin carries the transmit data from the Pmod system’s UART transmitter to a connected receiver. 3 RO Receiver output. This pin carries the half-duplex receive data to the Pmod system’s UART receiver. 4 DE Driver-output-enable input. This activehigh pin enables the half-duplex transmitter. 5 GND Ground 6 VCC Power supply Connector J2 provides the RS-485 positive and negative signal pair. See Table 2. Table 2. Connector J2 PIN SIGNAL DESCRIPTION 1 RS485-A Noninverting RS-485 signal 2 RS485-B Inverting RS-485 signal __________________________________________________________________ Maxim Integrated Products 2 MAX14840PMB1 Peripheral Module The software project (for the SDK) contains several source files intended to accelerate customer evaluation and design. These include a base application (maximModules.c) that demonstrates module functionality, and which uses an API interface (maximDeviceSpecific Utilities.c) to set and access Maxim device functions within a specific module. Connector JP1 (Termination Select) This jumper port optionally inserts a 120I termination resistor across the transmit-positive and negative nets. The JP1 jumper should be installed at the endpoints of the RS-485 network, and not at the midpoints. Software and FPGA Code Example software and drivers are available that execute directly without modification on several FPGA development boards that support an integrated or synthesized microprocessor. These boards include the Digilent Nexys 3, Avnet LX9, and Avnet ZEDBoard, although other platforms can be added over time. Maxim provides complete Xilinx ISE projects containing HDL, Platform Studio, and SDK projects. In addition, a synthesized bit stream, ready for FPGA download, is provided for the demonstration application. VCC The source code is written in standard ANSI C format, and all API documentation including theory/operation, register description, and function prototypes are documented in the API interface file (maximDeviceSpecificUtilities.h & .c). The complete software kit is available for download at www.maxim-ic.com. Quick start instructions are also available as a separate document. VCC C1 1uF GND J1 1 2 3 4 5 6 R1 R2 R3 R4 150 150 150 150 RE DI RO DE GND VCC 1 2 3 4 C2 0.1uF RS485-B GND 1 2 U1 RO VCC RE B DE A DI GND 8 7 VCC 6 5 JP1 2 R5 120 GND 1 J2 A B RS485-A MAX14840E Figure 1. MAX14840PMB1 Peripheral Module Schematic Figure 2. MAX14840PMB1 Peripheral Module Component Placement Guide—Component Side __________________________________________________________________ Maxim Integrated Products 3 MAX14840PMB1 Peripheral Module Figure 3. MAX14840PMB1 Peripheral Module PCB Layout—Component Side Figure 4. MAX14840PMB1 Peripheral Module PCB Layout—Inner Layer 1 (Ground) Figure 5. MAX14840PMB1 Peripheral Module PCB Layout—Inner Layer 2 (Power) __________________________________________________________________ Maxim Integrated Products 4 MAX14840PMB1 Peripheral Module Figure 6. MAX14840PMB1 Peripheral Module PCB Layout—Solder Side Figure 7. MAX14840PMB1 Peripheral Module Component Placement Guide—Solder Side __________________________________________________________________ Maxim Integrated Products 5 MAX14840PMB1 Peripheral Module Ordering Information PART TYPE MAX14840PMB1# Peripheral Module #Denotes RoHS compliant. __________________________________________________________________ Maxim Integrated Products 6 MAX14840PMB1 Peripheral Module Revision History REVISION NUMBER REVISION DATE 0 5/12 DESCRIPTION Initial release PAGES CHANGED — Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time. Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600 © 2012 Maxim Integrated Products 7 Maxim is a registered trademark of Maxim Integrated Products, Inc.