ATmega3290P datasheet(239/385 Pages) ATMEL

239 / 385 page

239

8021E–AVR–07/09

ATmega329P/3290P

• Bit 0 – LCDBL: LCD Blanking

When this bit is written to one, the display will be blanked after completion of a frame. All seg-

ment and common pins will be driven to ground.

22.5.2

LCDCRB – LCD Control and Status Register B

Note:

Bit 3, LCDPM3 is only available in ATmega3290P.

• Bit 7 – LCDCS: LCD Clock Select

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 Timer/Counter2” on page 149 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 ordinary port

pins. The different duty selections are shown in Table 22-2.

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 dif-

ferent selections are shown in Table 22-3. Unused pins can be used as ordinary port pins.

Bit

3210

(0xE5)

LCDCS

LCD2B

LCDMUX1

LCDMUX0

LCDPM3

LCDPM2

LCDPM1

LCDPM0

LCDCRB

Read/Write

R/W

Initial Value

0000

Table 22-2.

LCD Duty Select

LCDMUX1

LCDMUX0

Duty

Bias

COM Pin

I/O Port Pin

Static

COM0

COM1:3

1/2

1/2 or 1/3(1)

COM0:1

COM2:3

1/3

1/2 or 1/3(1)

COM0:2

COM3

1/4

1/2 or 1/3(1)

COM0:3

None

Table 22-3.

LCD Port Mask (Values in bold are only available in ATmega3290P)

LCDPM3

LCDPM2

LCDPM1

LCDPM0

I/O Port in Use as

Segment Driver

Maximum Number

of Segments

SEG0:12

SEG0:14

SEG0:16

SEG0:18

ATmega3290P Datasheet(PDF) 239 Page - ATMEL Corporation

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