313
XMEGA B [DATASHEET]
8291B–AVR–01/2013
Table 25-5. Segment terminal bus reverse (examples)
Note:
1.
Refer to specific device datasheet for availability of this feature.
Bit 2 – CLRDT: Clear Data Register
Writing this bit to one clears immediately the Display Memory (but not the control registers). The display will be blanked
after completion of a frame. This bit is automatically reset once the Display Memory is cleared.
Bit 1 – SEGON: Segments “ON”.
Writing this bit to one enables all segments and the contents of the Display Memory is output on the LCD. Writing it to
zero, turns “OFF” all LCD segments.
This bit can be used to flash the LCD, leaving the LCD timing generator enabled.
Bit 0 – BLANK: Blanking Display Mode
When this bit is written to one, the display will be blanked after completion of a frame. All segment and common terminals
will be driven to ground. (For more details see
“Display Blanking” on page 308
). This function does not modify the Display
Memory.
25.5.2 CTRLB – Control register B
Bit 7 – PRESC: LCD Prescaler Select
The PRESC bit selects a tap point from a ripple counter. The ripple counter output can be further divided by setting the
Clock Divider (CLKDIV[2:0]). The different selections are shown in
. Together they define the prescaler LCD
clock (clk
LCD_PS
), which is clocking the LCD controller.
Table 25-6. LCD prescaler selection.
PMSK[5:0]
Number of SEG
SEGSWP = 0
SEGSWP = 1
000100
4
(
SEG [39:4] unused
), SEG[3:0]
SEG[0:3], (
SEG[4:39] unused
)
001000
8
(
SEG[39:8] unused
), SEG[7:0]
SEG[0:7], (
SEG[8:39] unused
)
010000
16
(
SEG[39:16] unused
), SEG[15:0]
SEG[0:15], (
SEG[16:39] unused
)
101000
40
SEG[39:0]
SEG[0:39]
Bit
7
6
5
4
3
2
1
0
+0x01
PRESC
CLKDIV[2:0]
LPWAV
–
DUTY[1:0]
Read/Write
R/W
R/W
R/W
R/W
R/W
R
R/W
R/W
Initial Value
0
0
0
0
0
0
0
0
PRESC
Output From Ripple Counter
clk
LCD
/ N
Frame Rates ( CLKDIV[2:0] = 0, DUTY =
1
/
4
)
F(clk
LCD
) = 32kHz
F(clk
LCD
) = 32768Hz
0
clk
LCD
/
8
500 Hz
512 Hz
1
clk
LCD
/
16
250 Hz
256 Hz
Содержание XMEGA B
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