Build Your Own Hardware for Avise
(updated 31 Mar 2002)

The printed circuits presented here are kept quite simple due to the fact that most people who are interested to check out the possibilities of microcontrollers don't have the tools to produce sophisticated PCBs.

When the hardware is built up, the next step is to burn the program code of Avise into the CPU flash memory. To perform this, you need a serial programmer, which is temporarily connected with a ribbon cable to the Avise hardware.

PCB for AT90S8535

The first proposal is a design to run 'Avise2.4' with AT90S8535 CPU and one external serial EEPROM type 24C64 to 24C256 or equivalent types from different manufacturers, Microchip 24C65, e.g. The version for AT90S8535 without external EEPROM can be run on this PCB, too.
This design is very similar to the previous version for 'Avise 2.0' published here. But some fundamental changes have been made in the 'Avise' kernel. So, it is not interchangeable!


PCB assembly with simple RS-232 interface.

This PCB layout ist strictly held in 2.54 mm raster, this way - if no PCB can be etched - it is possible to wire the circuit completely 1:1 on a prototyping board with pad matrix (german: "Lochrasterplatte"). For wiring a solid silver plated copper wire with 0.5 to 0.6 mm diameter is recommended. I/O signals can be connected via a 40 pin IDC ribbon cable (IDE harddisk cable). The brownout detector MC34064P5 (=TL7757) is not absolutely necessary for proper function. The ceramic resonator must be a three pin type with built-in capacitors, max. frequency error 1%.
If only a subset of parts or I/O connections is needed for a certain application, wiring the prototyping board takes less work, of course. Parts of the circuit can be directly integrated into individual circuits built on a prototoyping board

The pinout of the ISP programming socket is now compatible with Atmel's AVR ISP and STK programmers.

The serial console interface is a dual standard layout: it can be assembled as a MIDI interface as well as for RS-232, 19200 Baud. The differences are described in the schematic. Unfortunately a 9 pin SubD socket does not fit into the 2.54 mm raster, but nevertheless the respective pads and wires have been placed on the board. When jumper J1 is inserted at power on, the serial interface does start with MIDI baudrate 31250 baud. When no jumper is present, it is set up with 19200 baud. This check-in is only performed once at power on or during the INIT command.

Alternative PCB assembly with MIDI interface. The serial receiver transistor of the RS-232 version is replaced here by an optocoupler.

For easy handling, the board is completed with a 5 volt regulator and a DC IN connector for common AC/DC adaptors (recommended: 7.5 to 12 volt unregulated). This connector does not exactly fit into the 2.54 mm matrix (manufacturer "ROKA", Conrad Electronic order nr. 73 79 92). In case, it can be replaced with a simple clamp. Some of the jumper wires were carried out as 10 Ohm resistors.

Last not least, one LED and two pushbuttons are provided on the board. But they are not necessary to operate 'Avise'.

For better readability, the circuit diagram and the assembly drawing and the PCB layout drawing have been put into separate files. To make your own films, be careful to print it with exact 100% size.

PCB for AT90LS4433 (or AT90S4433)

The second proposal is made for a minimum setup with AT90LS4433 CPU with or without external EEPROM of type 24C64, 24C65 or 24C256. This hardware is divided into a tiny "satellite module" and a simple "docking station" for power supply and programmer connection.

The PCB for the Avise module - together with its docking station - is single layer layouted. The small PCB for the 28 pin carrier is placed at the left side.

For the 'Avise2.41' firmware, the only absolutely necessary part is the ceramic resonator. It is a good idea to mount the AC bypass capacitor, even a conventional part with 2.54 mm wire spacing can be soldered onto the SMD pads. To install 'Avise2.42', only 3 SMD parts have to be mounted on the PCB copper side: the EEPROM, one resistor 4.7 kiloohms, and one AC bypass capacitor 100 to 220 nF. One jumper wire has to be assembled below the microcontroller. The AT90LS4433 controller is mounted conventionally with or without a socket. Furthermore, a four pin socket is provided for the RS-232 interface. Finally the assembled PCB is mounted on a 28 pin carrier (shopping source in Germany: Reichelt Elektronik, "http://www.reichelt.de", order code "AR28 "). If not available, you can assemble a standard 28 pin socket with short stubs of wire. With a thin solder tip it is possible to solder the PCB with its copper side down on the carrier.

The "docking station":

Schematic of the docking station:

Building this part is not tricky, anyway. Standard parts without special features can be used. All capacitors must be ceramic types except the electrolytic one. Some jumper wires are the price for the lowtech and easy reproducible PCB design.
The pinout of the ISP programming socket does differ from the commonly known standards. We use our own type of programmer which is assembled with a switch to connect the microcontroller SPI with the programmer or alternatively with the application. This way, no load restrictions or special hardware tricks have to be taken into account for serial programming. In a final state, the pins on the "docking station" are connected by solder.
The serial interface section can be equipped with 4 pin connector J16, which is compatible with the connector on the 'Avise' mini board. This way it can be used to run first steps of mobile robots controlled "by wire".

The PCB layout drawing has been put into a separate file. To make your own films, be careful to print it with exact 100% size.


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