swh:1:snp:77163734605b0ec556b01d897b7bb4a7e30d46b6
Tip revision: b37fa16e78d6f9790462b3181602a26b5af36260 authored by Linus Torvalds on 22 July 2010, 19:13:38 UTC
Linux 2.6.35-rc6
Linux 2.6.35-rc6
Tip revision: b37fa16
cfag12864b
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cfag12864b LCD Driver Documentation
===================================
License: GPLv2
Author & Maintainer: Miguel Ojeda Sandonis
Date: 2006-10-27
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0. INDEX
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1. DRIVER INFORMATION
2. DEVICE INFORMATION
3. WIRING
4. USERSPACE PROGRAMMING
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1. DRIVER INFORMATION
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This driver supports a cfag12864b LCD.
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2. DEVICE INFORMATION
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Manufacturer: Crystalfontz
Device Name: Crystalfontz 12864b LCD Series
Device Code: cfag12864b
Webpage: http://www.crystalfontz.com
Device Webpage: http://www.crystalfontz.com/products/12864b/
Type: LCD (Liquid Crystal Display)
Width: 128
Height: 64
Colors: 2 (B/N)
Controller: ks0108
Controllers: 2
Pages: 8 each controller
Addresses: 64 each page
Data size: 1 byte each address
Memory size: 2 * 8 * 64 * 1 = 1024 bytes = 1 Kbyte
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3. WIRING
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The cfag12864b LCD Series don't have official wiring.
The common wiring is done to the parallel port as shown:
Parallel Port cfag12864b
Name Pin# Pin# Name
Strobe ( 1)------------------------------(17) Enable
Data 0 ( 2)------------------------------( 4) Data 0
Data 1 ( 3)------------------------------( 5) Data 1
Data 2 ( 4)------------------------------( 6) Data 2
Data 3 ( 5)------------------------------( 7) Data 3
Data 4 ( 6)------------------------------( 8) Data 4
Data 5 ( 7)------------------------------( 9) Data 5
Data 6 ( 8)------------------------------(10) Data 6
Data 7 ( 9)------------------------------(11) Data 7
(10) [+5v]---( 1) Vdd
(11) [GND]---( 2) Ground
(12) [+5v]---(14) Reset
(13) [GND]---(15) Read / Write
Line (14)------------------------------(13) Controller Select 1
(15)
Init (16)------------------------------(12) Controller Select 2
Select (17)------------------------------(16) Data / Instruction
Ground (18)---[GND] [+5v]---(19) LED +
Ground (19)---[GND]
Ground (20)---[GND] E A Values:
Ground (21)---[GND] [GND]---[P1]---(18) Vee - R = Resistor = 22 ohm
Ground (22)---[GND] | - P1 = Preset = 10 Kohm
Ground (23)---[GND] ---- S ------( 3) V0 - P2 = Preset = 1 Kohm
Ground (24)---[GND] | |
Ground (25)---[GND] [GND]---[P2]---[R]---(20) LED -
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4. USERSPACE PROGRAMMING
------------------------
The cfag12864bfb describes a framebuffer device (/dev/fbX).
It has a size of 1024 bytes = 1 Kbyte.
Each bit represents one pixel. If the bit is high, the pixel will
turn on. If the pixel is low, the pixel will turn off.
You can use the framebuffer as a file: fopen, fwrite, fclose...
Although the LCD won't get updated until the next refresh time arrives.
Also, you can mmap the framebuffer: open & mmap, munmap & close...
which is the best option for most uses.
Check Documentation/auxdisplay/cfag12864b-example.c
for a real working userspace complete program with usage examples.