Atmel AVR2016, User Manual

Page: 9 / 25

Atmel AVR2016: RZRAVEN Hardware User’s Guide [APPLICATION NOTE]
8117E − AVR − 07/12
9
ISP programming can be performed by connecting an ISP enabled Atmel AVR programming tool to the pin header J302
(ATmega3290P) and J205 (ATmega1284P). AVR tools like Atmel STK
®
500, 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.
2.12.2 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.
2.13
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.
2.13.1 GPIO
Both the Atmel ATmega3290P and Atmel ATmega1284P are high pin count devices, and a number of these are not
used. These pins are available through the user I/O headers; J401, J201, J202 and J203. See
Table 2-2 and Table 2-3
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 Atmel AVRRAVEN.
Table 2-2. ATmega3290P User I/O.
ATmega3290P Port Pin PCB Connection Comment
PE3 J401-8 Via 470 Ω series resistor and10k Ω pull-up
PE4 J401-9 Via 470 Ω series resistor and10k Ω pull-up
PE5 J401-10 Via 470 Ω series resistor and10k Ω pull-up
PE6 J401-11 Via 470 Ω series resistor and10k Ω pull-up
Table 2-3. ATmega1284P User I/O.
ATmega1284P User I/O PCB Connection Comment
PC0 J201-1 TWI SCL.
Connected to serial EEPROM
PC1 J201-2 TWI SDA.
Connected to serial EEPROM
PC2 J201-3 JTAG TCK.
PC3 J201-4 JTAG TMS.
PC4 J201-5 JTAG TDO.
PC5 J201-6 JTAG TDI.
N.C. J201-7 Populate R204 to connect to PC6. RTC Xtal XC202 must then be
removed.