SMAR HI302, User Manual

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Basic Functioning Theory
6.4
To reduce the amount of components, increase trustability and make the hardware more
flexible, a EPLD, U10 programmable logic device has been used, including several
functions with combinational and sequential logic, such as frequency divisor for HART
modems, address decodifiers, etc. This component is fed with 3V3 and has 5V-compatible
inlets and outlets. One of its most important functions is to generate the clock for the
HART modems, stemming from the UART clock.
EPLD Programming
Update the EPLD programming in the circuit is also possible, due to the continuous
improvement in the equipment, though it should only be done in the factory.
Hand RESET key and FACTORY INIT
In the front side of the HI302 module there are two push button keys. One of them is the
Hand RESET button, connected to the U5, that covers the following components: HC11
(U1), FB3050 (U2), EPLD (U10) and UARTs (U7 and U8).
The other key cuts the power on the HC11, which initializes the memory and brings the
whole configuration back to the factory standard. This option is very useful in case of
malfunctioning due to configuration errors, as it reinstates the configuration memory in its
basic functional status.
ATTENTION
Do not press the Fct button when resetting the HI302, or else all the configuration will be
lost.
HI302 Module Resetting
The HI302 module has a very sophisticated resetting system, consisting of a circuit that
supervises the U5 feeding voltage and of several built-in mechanisms on the HC11
microcontroller, such as the WATCH DOG clock monitor. In addition, the RESET is used
by the U10 EPLD to adjust the firmware programming (resident program). When starting
up the module, the EPLD begins the device’s normal operation. If the RESET button is
pressed, the module enters in the BOOTLOADER mode, and is ready to update the
resident program on the FBTools. When the RESET button is pressed again, the module
gets back to normal operation.
IMPORTANT
As explained above, press the RESET button twice to get the HI302 adjusted for the
function.