Datasheet

234
ATmega329/3290/649/6490
2552I–AVR–04/07
When this bit is written to zero, the system clock is used. When this bit is written to one,
the external asynchronous clock source is used. The asynchronous clock source is
either Timer/Counter Oscillator or external clock, depending on EXCLK in ASSR. See
“Asynchronous operation of the Timer/Counter” on page 147 for further details.
• Bit 6 – LCD2B: LCD 1/2 Bias Select
When this bit is written to zero, 1/3 bias is used. When this bit is written to one, ½ bias is
used. Refer to the LCD Manufacture for recommended bias selection.
• Bit 5:4 – LCDMUX1:0: LCD Mux Select
The LCDMUX1:0 bits determine the duty cycle. Common pins that are not used are ordi-
nary port pins. The different duty selections are shown in Table 100.
Note: 1. 1/2 bias when LCD2B is written to one and 1/3 otherwise.
• Bits 3:0 – LCDPM3:0: LCD Port Mask
The LCDPM3:0 bits determine the number of port pins to be used as segment drivers.
The different selections are shown in Table 101. Unused pins can be used as ordinary
port pins.
Table 100. LCD Duty Select
LCDMUX1 LCDMUX0 Duty Bias COM Pin I/O Port Pin
0 0 Static Static COM0 COM1:3
0 1 1/2 1/2 or 1/3
(1)
COM0:1 COM2:3
101/31/2
or 1/3
(1)
COM0:2 COM3
111/41/2
or 1/3
(1)
COM0:3 None
Table 101. LCD Port Mask (Values in bold are only available in ATmega3290/6490)
LCDPM3 LCDPM2 LCDPM1 LCDPM0
I/O Port in Use as
Segment Driver
Maximum Number
of Segments
0 0 0 0 SEG0:12 13
0 0 0 1 SEG0:14 15
0 0 1 0 SEG0:16 17
0 0 1 1 SEG0:18 19
0 1 0 0 SEG0:20 21
0 1 0 1 SEG0:22 23
0 1 1 0 SEG0:23 24
0 1 1 1 SEG0:24 25
1 0 0 0 SEG0:26 27
1 0 0 1 SEG0:28 29
1 0 1 0 SEG0:30 31
1 0 1 1 SEG0:32 33
1 1 0 0 SEG0:34 35