iC-JX EVAL JX2D

Description

iC-JX is a bidirectional I/O device with 4x4 high-side driver stages. The input or output function can be separately selected for blocks or nibbles of four I/O stages. Each block can also be individually programmed with various filtering options for the debouncing of I/O pin signals or overcurrent messages, with current sources for the defining of levels at the inputs (low-side sources) or for load diagnosis at the outputs (high-side sources) and also with a flash pulse function. To enable communication with the controller the device includes a parallel interface (with eight data, five address and three control pins) and also an SPI compatible serial interface (with one pin for the clock, chip selection, data input and data output respectively). The type of interface is selected via pin NSP. I/O stages with an input function can record logic levels at 24 V where a programmable pull-down current source (of up to 2 mA) either defines the level for open inputs or supplies a bias current for external switch contacts. Connecting safety circuits with integrated serial/parallel resistors to the device also enables leakage currents and shor t circuits to be pinpointed. The contact status can be read out using the micro-controller interface. I/O stages with an output function drive various loads (such as lamps, cables or relays, for example) to a common ground with 150 mA of permanent current or 500 mA in pulse operation. Spikes and flyback currents are discharged by the integrated flyback circuits. For synchronous flash display, as used for indicator lamps in plugboards, for example, a flash pulse enable can be individually set for each output to offload the controller. A common inhibiting input (POE) permits the global shutdown of all outputs and can be operated by an autonomous watchdog circuit. All output stages are shor t-circuit-proof and protected against thermal destruction in the event of extreme power dissipation. Each stage has its own temperature sensor which is evaluated in two stages and generates interrupt messages for the controller. The latter is warned before the device is forcibly shut down. A shor t circuit also triggers an interrupt message; the current status here can be read out by the controller. For the pur pose of load diagnosis a programmable pull-up current source (of up to 2 mA) can be used to determine an initial load breakage or open loop (caused by a fractured cable, for example) before an output is switched on. The I/O pin status can always be read back via comparators. A load current measurement circuit then permits the load to be assessed; failed valves and faulty or wrongly implemented indicator lamps can be verified in this way. In addition, the analog measurement of voltage at the I/O pins allows safety switches to be analyzed with reference to ground, here without the driver function. All analog measurements for the load current (per stage), for the I/O pin voltage (per stage, either referenced to ground or VB), for the driver supply (all VB pins) , for the internal voltage reference (VBG) and for the chip temperature are made available to the micro-controller as digital measurements by an integrated A/D conver ter which has 10 bits of resolution. An interrupt pipeline which limits the loss of interrupts allows reliable processing of interrupts by the micro-controller. Registers provide information as to current events; messages can be individually enabled for all available interrupt sources. iC-JX monitors all supply voltages and also the GNDD-GNDA connection to ground. Monitored separately, under voltage in the range of 2.5V at analog supply VCC or even short disruption of digital supply VDD causes all registers to be reset and the output stages to be shutdown. Under voltage at 24 V driver supply VB triggers a shutdown of the output stages without deleting the contents of the registers. Diodes protect all inputs and outputs against destruction by ESD. iC-JX is also immune to burst transients according to IEC 1000-4-4 (4 kV; previously IEC 801-4).

Features