AT90CAN64 datasheet(71/431 Pages) ATMEL

71 / 431 page

7682C–AUTO–04/08

AT90CAN32/64/128

above mentioned sleep modes, as the clamping in these sleep modes produces the requested

logic change.

9.2.6

Unconnected Pins

If some pins are unused, it is recommended to ensure that these pins have a defined level. Even

though most of the digital inputs are disabled in the deep sleep modes as described above, float-

ing inputs should be avoided to reduce current consumption in all other modes where the digital

inputs are enabled (Reset, Active mode and Idle mode). The simplest method to ensure a

defined level of an unused pin, is to enable the internal pull-up. In this case, the pull-up will be

disabled during reset. If low power consumption during reset is important, it is recommended to

use an external pull-up or pull-down. Connecting unused pins directly to VCC or GND is not rec-

ommended, since this may cause excessive currents if the pin is accidentally configured as an

output.

9.3

Alternate Port Functions

Most port pins have alternate functions in addition to being general digital I/Os. Figure 9-5 shows

how the port pin control signals from the simplified Figure 9-2 can be overridden by alternate

functions. The overriding signals may not be present in all port pins, but the figure serves as a

generic description applicable to all port pins in the AVR microcontroller family.

AT90CAN64 Datasheet(PDF) 71 Page - ATMEL Corporation