77
2467S–AVR–07/09
ATmega128
Alternate Functions of
Port C
In ATmega103 compatibility mode, Port C is output only. The ATmega128 is by default shipped
in compatibility mode. Thus, if the parts are not programmed before they are put on the PCB,
PORTC will be output during first power up, and until the ATmega103 compatibility mode is dis-
abled. The Port C has an alternate function as the address high byte for the External Memory
Interface.
Table 34 and Table 35 relate the alternate functions of Port C to the overriding signals shown in
Figure 33 on page 71.
Note: 1. XMM = 0 in ATmega103 compatibility mode.
Table 33. Port C Pins Alternate Functions
Port Pin Alternate Function
PC7 A15
PC6 A14
PC5 A13
PC4 A12
PC3 A11
PC2 A10
PC1 A9
PC0 A8
Table 34. Overriding Signals for Alternate Functions in PC7..PC4
Signal
Name PC7/A15 PC6/A14 PC5/A13 PC4/A12
PUOE SRE • (XMM
(1)
<1) SRE • (XMM<2) SRE • (XMM<3) SRE • (XMM<4)
PUOV 0 0 0 0
DDOE SRE • (XMM<1) SRE • (XMM<2) SRE • (XMM<3) SRE • (XMM<4)
DDOV 1 1 1 1
PVOE SRE • (XMM<1) SRE • (XMM<2) SRE • (XMM<3) SRE • (XMM<4)
PVOV A15 A14 A13 A12
DIEOE 0 0 0 0
DIEOV 0 0 0 0
DI – – – –
AIO – – – –
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