Rainbow-electronics ATmega32L Instrukcja Użytkownika Pobierz pdf (Strona 59)

ATmega32(L)

2503C–AVR–10/02

• TCK – Port C, Bit 2

TCK, JTAG Test Clock: JTAG operation is synchronous to TCK. When the JTAG inter-

face is enabled, this pin can not be used as an I/O pin.

• SDA – Port C, Bit 1

SDA, Two-wire Serial Interface Data: When the TWEN bit in TWCR is set (one) to

enable the Two-wire Serial Interface, pin PC1 is disconnected from the port and

becomes the Serial Data I/O pin for the Two-wire Serial Interface. In this mode, there is

a spike filter on the pin to suppress spikes shorter than 50 ns on the input signal, and the

pin is driven by an open drain driver with slew-rate limitation. When this pin is used by

the Two-wire Serial Interface, the pull-up can still be controlled by the PORTC1 bit.

• SCL – Port C, Bit 0

SCL, Two-wire Serial Interface Clock: When the TWEN bit in TWCR is set (one) to

enable the Two-wire Serial Interface, pin PC0 is disconnected from the port and

becomes the Serial Clock I/O pin for the Two-wire Serial Interface. In this mode, there is

a spike filter on the pin to suppress spikes shorter than 50 ns on the input signal, and the

pin is driven by an open drain driver with slew-rate limitation. When this pin is used by

the Two-wire Serial Interface, the pull-up can still be controlled by the PORTC0 bit.

Table 29 and Table 30 relate the alternate functions of Port C to the overriding signals

shown in Figure 26 on page 52.

Table 29. Overriding Signals for Alternate Functions in PC7..PC4

Signal

Name PC7/TOSC2 PC6/TOSC1 PC5/TDI PC4/TDO

PUOE AS2 AS2 JTAGEN JTAGEN

PUOV 0 0 1 0

DDOE AS2 AS2 JTAGEN JTAGEN

DDOV 0 0 0 SHIFT_IR + SHIFT_DR

PVOE 0 0 0 JTAGEN

PVOV 0 0 0 TDO

DIEOE AS2 AS2 JTAGEN JTAGEN

DIEOV 0 0 0 0

DI – – – –

AIO T/C2 OSC OUTPUT T/C2 OSC INPUT TDI –

1 2 ... 54 55 56 57 58 59 60 61 62 63 64 ... 312 313

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Rainbow-electronics ATmega32L Instrukcja Użytkownika Strona 59