Based on kernel version 4.16.1. Page generated on 2018-04-09 11:52 EST.
1 =================================== 2 cfag12864b LCD Driver Documentation 3 =================================== 4 5 License: GPLv2 6 Author & Maintainer: Miguel Ojeda Sandonis 7 Date: 2006-10-27 8 9 10 11 -------- 12 0. INDEX 13 -------- 14 15 1. DRIVER INFORMATION 16 2. DEVICE INFORMATION 17 3. WIRING 18 4. USERSPACE PROGRAMMING 19 20 21 --------------------- 22 1. DRIVER INFORMATION 23 --------------------- 24 25 This driver supports a cfag12864b LCD. 26 27 28 --------------------- 29 2. DEVICE INFORMATION 30 --------------------- 31 32 Manufacturer: Crystalfontz 33 Device Name: Crystalfontz 12864b LCD Series 34 Device Code: cfag12864b 35 Webpage: http://www.crystalfontz.com 36 Device Webpage: http://www.crystalfontz.com/products/12864b/ 37 Type: LCD (Liquid Crystal Display) 38 Width: 128 39 Height: 64 40 Colors: 2 (B/N) 41 Controller: ks0108 42 Controllers: 2 43 Pages: 8 each controller 44 Addresses: 64 each page 45 Data size: 1 byte each address 46 Memory size: 2 * 8 * 64 * 1 = 1024 bytes = 1 Kbyte 47 48 49 --------- 50 3. WIRING 51 --------- 52 53 The cfag12864b LCD Series don't have official wiring. 54 55 The common wiring is done to the parallel port as shown: 56 57 Parallel Port cfag12864b 58 59 Name Pin# Pin# Name 60 61 Strobe ( 1)------------------------------(17) Enable 62 Data 0 ( 2)------------------------------( 4) Data 0 63 Data 1 ( 3)------------------------------( 5) Data 1 64 Data 2 ( 4)------------------------------( 6) Data 2 65 Data 3 ( 5)------------------------------( 7) Data 3 66 Data 4 ( 6)------------------------------( 8) Data 4 67 Data 5 ( 7)------------------------------( 9) Data 5 68 Data 6 ( 8)------------------------------(10) Data 6 69 Data 7 ( 9)------------------------------(11) Data 7 70 (10) [+5v]---( 1) Vdd 71 (11) [GND]---( 2) Ground 72 (12) [+5v]---(14) Reset 73 (13) [GND]---(15) Read / Write 74 Line (14)------------------------------(13) Controller Select 1 75 (15) 76 Init (16)------------------------------(12) Controller Select 2 77 Select (17)------------------------------(16) Data / Instruction 78 Ground (18)---[GND] [+5v]---(19) LED + 79 Ground (19)---[GND] 80 Ground (20)---[GND] E A Values: 81 Ground (21)---[GND] [GND]---[P1]---(18) Vee - R = Resistor = 22 ohm 82 Ground (22)---[GND] | - P1 = Preset = 10 Kohm 83 Ground (23)---[GND] ---- S ------( 3) V0 - P2 = Preset = 1 Kohm 84 Ground (24)---[GND] | | 85 Ground (25)---[GND] [GND]---[P2]---[R]---(20) LED - 86 87 88 ------------------------ 89 4. USERSPACE PROGRAMMING 90 ------------------------ 91 92 The cfag12864bfb describes a framebuffer device (/dev/fbX). 93 94 It has a size of 1024 bytes = 1 Kbyte. 95 Each bit represents one pixel. If the bit is high, the pixel will 96 turn on. If the pixel is low, the pixel will turn off. 97 98 You can use the framebuffer as a file: fopen, fwrite, fclose... 99 Although the LCD won't get updated until the next refresh time arrives. 100 101 Also, you can mmap the framebuffer: open & mmap, munmap & close... 102 which is the best option for most uses. 103 104 Check samples/auxdisplay/cfag12864b-example.c 105 for a real working userspace complete program with usage examples.