AVR2016
4.4 Interfaces Figure 4-2 RZUSBSTICK Interfaces - front.
Figure 4-3 RZUSBSTICK Interfaces - back
4.4.1 External Memory Interface
When necessary the AT90USB1287’s 8k Bytes of internal SRAM can be extended
through the AVR external memory interface. The suggested external SRAM is 32k
Bytes and is available from address 0x8000 to 0xFFFF giving a total of 40k Bytes
when assembled.
Suggested latch and RAM:
• 74AHC573PW.
• BS62UV256TCP-10.
4.4.2 Serial Interface
The USART on the AT90USB1287 is routed to J4 on the 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.
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