ATMEGA169 ATMEL [ATMEL Corporation], ATMEGA169 Datasheet - Page 62

• Manufacturer Part Number: ATMEGA169
• Description: 8-bit Microcontroller with 16K Bytes In-System Programmable Flash
• Manufacturer: ATMEL [ATMEL Corporation]

MCU Control Register –
MCUCR
Alternate Functions of Port A
62
ATmega169/V
• 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 56 for more details about this feature.
The Port A has an alternate function as COM0:3 and SEG0:3 for the LCD Controller.
Table 27. Port A Pins Alternate Functions
Table 28 and Table 29 relates the alternate functions of Port A to the overriding signals
shown in Figure 26 on page 60.
Table 28. Overriding Signals for Alternate Functions in PA7..PA4
Bit
Read/Write
Initial Value
Signal Name
PUOE
PUOV
DDOE
DDOV
PVOE
PVOV
PTOE
DIEOE
DIEOV
DI
AIO
Port Pin
PA7
PA6
PA5
PA4
PA3
PA2
PA1
PA0
JTD
R/W
7
0
PA7/SEG3
LCDEN
0
LCDEN
0
0
0
–
LCDEN
0
–
SEG3
R
6
–
0
Alternate Function
SEG3 (LCD Front Plane 3)
SEG2 (LCD Front Plane 2)
SEG1 (LCD Front Plane 1)
SEG0 (LCD Front Plane 0)
COM3 (LCD Back Plane 3)
COM2 (LCD Back Plane 2)
COM1 (LCD Back Plane 1)
COM0 (LCD Back Plane 0)
R
5
–
0
PA6/SEG2
LCDEN
0
LCDEN
0
0
0
–
LCDEN
0
–
SEG2
PUD
R/W
4
0
R
3
–
0
PA5/SEG1
LCDEN
0
LCDEN
0
0
0
–
LCDEN
0
–
SEG1
R
2
–
0
IVSEL
R/W
1
0
PA4/SEG0
LCDEN
0
LCDEN
0
0
0
–
LCDEN
0
–
SEG0
IVCE
R/W
2514P–AVR–07/06
0
0
MCUCR