Rainbow-electronics Atmega169L Manuel d'utilisateur télécharger pdf (Page 57)

ATmega169V/L

2514A–AVR–08/02

MCU Control Register –

MCUCR

• Bit 4 – PUD: Pull-up Disable

When this bit is written to one, the pull-ups in the I/O ports are disabled even if the DDxn

and PORTxn Registers are configured to enable the pull-ups ({DDxn, PORTxn} = 0b01).

See “Configuring the Pin” on page 51 for more details about this feature.

Alternate Functions of Port A The Port A has an alternate function as COM0:3 and SEG0:3 for the LCD Controller.

Table 27 and Table 28 relates the alternate functions of Port A to the overriding signals

shown in Figure 25 on page 55.

Bit 7 6 5 4 3 2 1 0

JTD – – PUD – – IVSEL IVCE MCUCR

Read/Write R/W R R R/W R R R/W R/W

Initial Value 0 0 0 0 0 0 0 0

Table 26. Port A Pins Alternate Functions

Port Pin Alternate Function

PA7 SEG3 (LCD Front Plane 3)

PA6 SEG2 (LCD Front Plane 2)

PA5 SEG1 (LCD Front Plane 1)

PA4 SEG0 (LCD Front Plane 0)

PA3 COM3 (LCD Back Plane 3)

PA2 COM2 (LCD Back Plane 2)

PA1 COM1 (LCD Back Plane 1)

PA0 COM0 (LCD Back Plane 0)

Table 27. Overriding Signals for Alternate Functions in PA7..PA4

Signal Name PA7/SEG3 PA6/SEG2 PA5/SEG1 PA4/SEG0

PUOE LCDEN LCDEN LCDEN LCDEN

PUOV0000

DDOE LCDEN LCDEN LCDEN LCDEN

DDOV 0 0 0 0

PVOE0000

PVOV0000

PTOE ––––

DIEOE LCDEN LCDEN LCDEN LCDEN

DIEOV0000

DI ––––

AIO SEG3 SEG2 SEG1 SEG0

1 2 ... 52 53 54 55 56 57 58 59 60 61 62 ... 316 317

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Rainbow-electronics Atmega169L Manuel d'utilisateur Page 57