The AVRRAVEN module has multiple interfaces that can be used for serial communication, interaction with external sensors and control units such as relays and of course programming and debugging.
| Pin number | Function | Comment |
|---|---|---|
| 1 | Ext. power supply, 5-12V input | External power input |
| 2 | Ext. power supply 0V | Connected to internal 0V |
| 3 | Relay coil positive | Relay driver circuit pos. |
| 4 | Relay coil negative | Relay driver circuit neg. |
| 5 | Voltage measure input, 0-Vcc*5 | Analog input via 47k/10k voltage divider |
| 6 | Voltage measure input, 0-Vcc | Analog input directly to ADC input. |
| 7 | Vcc | Connected to the VCC net directly |
| 8 | User IO #1 | Digital I/O, may interface an LED or a switch directly. Internal 470Ω series resistor, and 10kΩ pull-ups are provided 11 User IO #4 Pin change interrupts, TWI and USI is also available on these pins. 12 Common Connected to internal 0V |
| 9 | User IO #2 | |
| 10 | User IO #3 | |
| 11 | User IO #4 | Pin change interrupts, TWI and USI is also available on these pins. |
| 12 | Common | Connected to internal 0V |
Care should be taken when connecting to the AVRRAVEN's interfaces, since there is no protection circuitry provided. Damage to the MCUs or other circuits may be the result of ESD spark, short circuits, polarity or over-voltage faults.
Programming Interface
Both the ATmega3290P and ATmega1284P can be programmed using either the JTAG or ISP interface. JTAG programming can be facilitated by connecting a JTAG ICE mkII to the 50-mil pin header J301 (ATmega3290P) and J204 (ATmega1284P). A total of 5 50-mil pin headers and one 50-mil to 100-mil converter are supplied with the RZRAVEN kit.
ISP programming can be performed by connecting an ISP enabled AVR programming tool to the pin header J302 (ATmega3290P) and J205 (ATmega1284P). AVR tools like STK500, AVRISP mkII and JTAGICE mkII can be used for this. The AVRRAVEN does not come with these headers mounted. So it is up to the user populating these. Wires could also be soldered in instead of the dual row headers.
Relay interface
A relay interface (Relay Positive and Negative) is available through J401. This interface can be used with the AVRRAVEN running from external power. A switching transistor is connected to PB6 on the ATmega3290P so that sufficient current can be provided to the relay being driven. An external power source must be used if the relay option is required. The AVRRAVEN must then be supplied with the rated voltage of the relay.