8 AVR2016 8117D-AVR-04/08
3.12.1 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.
3.12.2 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.
3.13 Voltage Measurement Interface
Two of the pins in header J401 can be used for external voltage measurements,
however only one at the time. The possible voltage ranges are 0 to VCC or via a
voltage divider giving an approximate range of 0 to five times VCC. A simple voltage
divider is implemented to scale the measurement voltage. A diode bridge is also used
to prevent reverse polarity and to protect the ATmega3290P’s ADC channel 3.
3.13.1 GPIO
Both the ATmega3290P and ATmega1284P are high pin count devices, and a
number of these are not used. These pins are available through the user IO headers;
J401, J201, J202 and J203. See Table 3-2 and Table 3-3 for further details.
Be aware that these pins do not have level converters and should thus not be
connected directly to an application board running on a different voltage level than the
AVRRAVEN.
Table 3-2. ATmega3290P User IO
ATmega3290P Port Pin PCB Connection Comment
PE3 J401 –8
Via 470Ω series resistor
and10kΩ pull-up
PE4 J401-9
Via 470Ω series resistor
and10kΩ pull-up
PE5 J401-10
Via 470Ω series resistor
and10kΩ pull-up
PE6 J401-11
Via 470Ω series resistor
and10kΩ pull-up