Mcucr - mcu control register, Alternate functions of port a – Rainbow Electronics ATmega3290P_V User Manual
Page 67
67
ATmega329/3210/649/6410
2552H–AVR–11/06
MCUCR – MCU Control
Register
• 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 60 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 28 and Table 29 relates the alternate functions of Port A to the overriding signals
shown in Figure 27 on page 65.
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 27. Port A Pins Alternate Functions
Port Pin
Alternate Function
PA7
SEG (LCD Front Plane 3)
PA6
SEG (LCD Front Plane 2)
PA5
SEG (LCD Front Plane 1)
PA4
SEG (LCD Front Plane 0)
PA3
COM (LCD Back Plane 3)
PA2
COM (LCD Back Plane 2)
PA1
COM (LCD Back Plane 1)
PA0
COM (LCD Back Plane 0)
Table 28. Overriding Signals for Alternate Functions in PA7..PA4
Signal
Name
PA7/SEG3
PA6/SEG2
PA5/SEG1
PA4/SEG0
PUOE
LCDEN
LCDEN
LCDEN
LCDEN
PUOV
0
0
0
0
DDOE
LCDEN
LCDEN
LCDEN
LCDEN
DDOV
0
0
0
0
PVOE
0
0
0
0
PVOV
0
0
0
0
PTOE
–
–
–
–
DIEOE
LCDEN
LCDEN
LCDEN
LCDEN
DIEOV
0
0
0
0
DI
–
–
–
–
AIO
LCDSEG
LCDSEG
LCDSEG
LCDSEG