Atmel AVR2016, User Manual

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Atmel AVR2016: RZRAVEN Hardware User’s Guide [APPLICATION NOTE]
8117E − AVR − 07/12
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3.4.2 External Memory Interface
When necessary the Atmel AT90USB1287’s 8kB of internal SRAM can be extended through the AVR external memory
interface. The suggested external SRAM is 32kB and is available from address 0x8000 to 0xFFFF giving a total of 40kB
when assembled.
Suggested latch and RAM:
•
74AHC573PW
•
BS62UV256TCP-10
3.4.3 Serial Interface
The USART on the Atmel AT90USB1287 is routed to J4 on the Atmel RZRAVEN’s backside. J4 is implemented as
three large pads (RX-TX-GND) where the user can solder in wires and route the signal to his or her preference. The
RX-TX signals are TTL level, so an external level converter must be connected if RS232 levels are necessary.
3.4.4 Programming Interface
A JTAG interface is provided for the AT90USB1287 microcontroller. The interface is available through a 50-mil spaced
10-pin dual row header. The RZRAVEN does not come with the header mounted. So it is up to the user populating it.
Wires could also be soldered in instead of the dual row headers. A total of 5 50-mil pin headers and one 50-mil to 100-
mil converter are supplied with the RZRAVEN kit.
3.4.5 LEDs
Four LEDs are assembled on the board:
Table 3-1. Atmel AT90USB1287 LEDs.
LED AT90USB1297
Port Pin Comment
Blue (D1) PORTD7 Turn LED on by pulling port pin high
Red (D2) PORTD5 Turn LED on by pulling port pin low
Green (D3) PORTE7 Turn LED on by pulling port pin low
Orange (D4) PORTE5 Turn LED on by pulling port pin high