Embedded Systems. Prof. Myung-Eui Lee (A-405) 1-1. Embedded Systems KUT

Transcription

1 Prof. Myung-Eui Lee (A-) -

2 Device driver Appication Area Appication System Ca Interface Virtua Fie System (VFS) Kerne Area Buffer Cache Network Subsystem BSD socket Inet (AF_INET) Transport(TCP, UDP) Character Device Driver Bock Device Driver Network Device Driver Network (IP) Device Interface Hardware Hardware -

3 Virtua Fie System. process process process n User Mode Virtua Fie System System Mode minix nfs Ext/3 dos. dev proc buffer cache Fie System Device Driver -3

4 VFS Virtua Fie System» Not a fie system on its own but an interface» Kerne software ayer that handes a system cas reated to a standard Unix fie system» Link between the operating system kerne and the different fie systems» Suppies the appications with the system cas for fie management» Passes tasks to the appropriate actua fie system Fie system supported by VFS» Disk-based fie system u Ext/3, dos, vfat, ntfs, hpfs (IBM s OS/), hfs (Appe s Mac OS)» Network fie system u NFS, SMB(SaMBa), NCP(Nove s NetWare Core Protoco)» Specia fie system u /proc/*, /dev/* -

5 VFS VFS objects» superbock object : specific mounted fie system u struct super_bock, struct super_operations (incude/inux/fs.h)» dentry object : represents directory entry u struct dentry, struct dentry_operations (incude/inux/dcache.h)» inode object : represents a specific fie > s -i u struct inode, struct inode_operations (incude/inux/fs.h)» fie object : represents a fie opened by a process u struct fie, struct fie_operations (incude/inux/fs.h) -

6 struct fie Type Fied Description struct fie *f_next Pointer to next fie object struct fie **f_pprev Pointer to previous fie object struct dentry struct fie_operations mode_t *f_dentry *f_op f_mode Pointer to associated dentry object Pointer to fie operation tabe Process access mode off_t unsigned int unsigned int unsigned ong unsigned ong f_pos f_count f_fags f_reada f_ramax Current fie offset (fie pionter) Fie object's usage counter Fags specified when opening the fie Read-ahead fag Maximum number of pages to be read-ahead unsigned ong unsigned ong unsigned ong struct fown_struct unsigned int unsigned int int unsigned ong f_raend f_raen f_rawin f_owner f_uid f_gid f_error f_version Fie pointer after ast read-ahead Number of read-ahead bytes Number of read-ahead pages Data for asynchronous I/O via signas User's UID User's GID Error code for networkwrite operation Version number, automaticay incremented after each use void *private_data Needed for tty driver Understanding the Linux Kerne, O reiy,, Ver.. 초기 -6

7 struct fie -.6 u /pxa7/kerne/inux-.6.-h7-tku_v./incude/ inux/fs.h struct fie { struct ist_head f_ist; struct dentry *f_dentry; struct vfsmount *f_vfsmnt; struct fie_operations *f_op; atomic_t f_count; unsigned int f_fags; mode_t f_mode; int f_error; off_t f_pos; struct fown_struct f_owner; unsigned int f_uid, f_gid; struct fie_ra_state f_ra; size_t f_maxcount; unsigned ong f_version; void *f_security; /* needed for tty driver, and maybe others */ void *private_data; #ifdef CONFIG_EPOLL /* Used by fs/eventpo.c to ink a the hooks to this fie */ struct ist_head f_ep_inks; spinock_t f_ep_ock; #endif /* #ifdef CONFIG_EPOLL */ struct address_space *f_mapping; ; -7

8 struct fie_operations -.6 struct fie_operations { struct modue *owner; off_t (*seek) (struct fie *, off_t, int); ssize_t (*read) (struct fie *, char user *, size_t, off_t *); ssize_t (*aio_read) (struct kiocb *, char user *, size_t, off_t); ssize_t (*write) (struct fie *, const char user *, size_t, off_t *); ssize_t (*aio_write) (struct kiocb *, const char user *, size_t, off_t); int (*readdir) (struct fie *, void *, fidir_t); unsigned int (*po) (struct fie *, struct po_tabe_struct *); int (*ioct) (struct inode *, struct fie *, unsigned int, unsigned ong); ong (*unocked_ioct) (struct fie *, unsigned int, unsigned ong); ong (*compat_ioct) (struct fie *, unsigned int, unsigned ong); int (*mmap) (struct fie *, struct vm_area_struct *); int (*open) (struct inode *, struct fie *); int (*fush) (struct fie *); int (*reease) (struct inode *, struct fie *); int (*fsync) (struct fie *, struct dentry *, int datasync); int (*aio_fsync) (struct kiocb *, int datasync); int (*fasync) (int, struct fie *, int); int (*ock) (struct fie *, int, struct fie_ock *); ssize_t (*readv) (struct fie *, const struct iovec *, unsigned ong, off_t *); ssize_t (*writev) (struct fie *, const struct iovec *, unsigned ong, off_t *); ssize_t (*sendfie) (struct fie *, off_t *, size_t, read_actor_t, void *); ssize_t (*sendpage) (struct fie *, struct page *, int, size_t, off_t *, int); unsigned ong (*get_unmapped_area)(struct fie *, unsigned ong, unsigned ong, unsigned ong, unsigned ong); int (*check_fags)(int); int (*dir_notify)(struct fie *fip, unsigned ong arg); int (*fock) (struct fie *, int, struct fie_ock *); ; -8

9 fie operations seek(fie, offset, int) Updates the fie pointer to given offset read(fie, buf, count, offset) Reads count bytes from a fie starting at position *offset into buf; the vaue *offset (which usuay corresponds to the fie pointer) is then incremented. write(fie, buf, count, offset) Writes count bytes into a fie starting at position *offset from buf; the vaue (which usuay corresponds to the fie pointer) is then incremented. readdir(dir, dirent, fidir) Returns the next directory entry of a directory in dirent; the fidir parameter contains the address of an auxiiary function that extracts the fieds in a directory entry. po(fie, po_tabe) Checks whether there is activity on a fie and goes to seep unti something happens on it. ioct(inode, fie, cmd, arg) Sends a command to an underying hardware device. This method appies ony to device fies. mmap(fie, vma) Performs a memory mapping of the fie into a process address space. open(inode, fie) Opens a fie by creating a new fie object and inking it to the corresponding inode object. -9

10 fie operations fush(fie) Caed when a reference to an open fie is cosed, that is, the data in buff is deeted. reease(inode, fie) = cose Reeases the fie object fsync(fie, dentry) Writes a cached data of the fie to disk. fasync(fie, int) Enabes or disabes asynchronous I/O notification by means of signas. check_media_change(dev) Checks whether there has been a change of media since the ast operation on the device fie (appicabe to bock devices that support removabe media, such as foppies and CD-ROMs). revaidate(dev) Restores the consistency of a device (used by network fie systems after a media change has been recognized on a remote device). ock(fie, cmd, fie_ock) Appies a ock to the fie -

11 Device driver -

12 Device driver Device fie types cd /dev, s -a». character : c u byte (sequentia) process, no buffer cache». bock : b u bock (random) process, buffer cache» 3. network u packet process, socket (protoco stack) brw-r----- root disk 3 Oct 3 6 hda brw-r----- root disk 3 Oct 3 6 hda brw-r----- root disk 3 Oct 3 6 hda brw-r----- root disk 3 3 Oct 3 6 hda3 crw--w--w-- card tty May 6 6 tty crw--w--w-- card tty May 6 6 tty crw--w--w-- card tty May 6 6 tty... -

13 Device driver Device fie» major number u incude/inux/major.h, Documentation/devices.txt, more /proc/devices» minor number Major Character devices Bock devices unnamed unnamed physica memory access(/dev/mem) First RAM disk(dev/ram) Kerne virtua memory(/dev/kmem) foppy (fd*) 3 IDE hard disk (hd* ) termina termina & AUX 6 Parae Interface 7 virtua consoe (vcs*) 8 SCSI hard disk (sd*) 9 SCSI tapes (st*) Bus mice(bm, psaux) SCSI CD-ROM(scd*) 3 Mitsumi CD-ROM (mcd*). -3

14 Device number» Major : device type» Minor : device unit /dev/tty, /dev/hdb /dev/tty, /dev/tty, system /dev/hdb 3,6 /dev/hdb3 3,67 /dev/hdb 3,66 /dev/hda /dev/tty3,3 /dev/hda 3, /dev/hda 3, /dev/hda3 3,3 -

15 Character devices Device Driver-.6 /pxa7/kerne/inux-.6.-h7-tku_v./fs/char_dev.c» insmod register_chrdev() (3, * name, *fops) : auto = Major number MAX_CHRDEV chrdevs[] char_device_struct struct char_device_struct { name; struct fie_operations * fops; ;.. struct char_device_struct chrdevs[max_chrdev] fie_operations seek read, write, readdir po, ioct, mmap, open, fush, reease fsync,.. Refer to side #36 -

16 Bock devices Device Driver -.6 /pxa7/kerne/inux-.6.-h7-tku_v./fs/bock_dev.c» inode function struct fie_operations def_bk_fops = {.open.reease.seek.read.write - -.mmap.fsync.ioct ; struct bdev_inode { struct bock_device bdev; struct inode vfs_inode; ; = bkdev_open, = bkdev_cose, = bock_seek, = generic_fie_read, = bkdev_fie_write, = generic_fie_mmap, = bock_fsync, = bock_ioct /pxa7/kerne/inux-.6.-h7-tku_v./incude/inux/fs.h struct bock_device { dev_t bd_dev; /* not a kdev_t - it's a search key */ struct inode * bd_inode; /* wi die */ int bd_openers;.... ; -6

17 IEB Board Memory Mapped I/O Memory Mapped I/O xffff FFFF xb xac xa8 xa xa xc x8 x x x3 x x8 x x xc x8 x x Reserved(Mbytes) SDRAM BANK 3(6Mbytes) SDRAM BANK (6Mbytes) SDRAM BANK (6Mbytes) SDRAM BANK (6Mbytes) Reserved(3Mbytes) Interna SRAM (C - C3 FFFF) Memory Mapped registers (Memory Ct) (6Mbyte) Memory Mapped registers (LCD) (6Mbyte) Memory Mapped registers (Peripheras) (6MBytes) PCMCIA Socket Space (6Mbyte) PCMCIA Socket Space (6Mbyte) Reserved(8 Mbytes) Static Bank Seect (6Mbytes) Static Bank Seect (6Mbytes) Static Bank Seect 3(6Mbytes) Static Bank Seect (6Mbytes) Static Bank Seect (6Mbytes) Static Bank Seect (6Mbytes) Name Address Size Description FND x x 7-segment FND x x 7-segment FND3 x x 7-segment 3 FND x3 x 7-segment FND x x 7-segment FND6 x x 7-segment 6 FND7 x6 x 7-segment 7 FND8 x7 x 7-segment 8 DOT_ Co x8 x Dot coumn DOT_ Co x9 x Dot coumn DOT_3 Co xa x Dot coumn 3 DOT_ Co xb x Dot coumn DOT_ Co xc x Dot coumn KEY_W xd x Key Write KEY_R xe x Key Read DAC xf x Digita to Anaog Converter ADC x x Anaog to Digita Converter STEP Motor x x Step Motor controer DC Motor x x DC Motor controer Character LCD x3 x Character LCD Contro LED x x LED -7

18 ncs<> -8

19 Address Mapping Address[..] FND ~8 x_ ~ x7_ BULVERDE PXA7 Data[3..] ncs ncs ncs ncs CPLD XCC6 Address[..] Data[3..] ncs FPGA EPC6OPQFP DOT Co~Co KEY W, R STEP MOTOR DC MOTOR x8_ ~ xc_ x_, xe_ x_ x_ CLCD RS, W/R x3_, x38_ LED x_ PXA7 I/O Devices Cache MMU Static mem. Con. Address Data FPGA Cotro FND DOT Key Step motor DC motor CLCD LED Address Decoding Virtua Address Physica Address -9

20 Address Decoder LED» 8 Bit Write [ D~D7 ]» Base Address = x LED-CS D[...7] LED-CS# D D D D3 D D D6 D D Q D Q D Q D3 Q3 D Q D Q D6 Q6 D7 Q7 OC CLK 7LCX LED LED3 LED LED7 LED LED LED6 LED DCV -

21 Device driver Device driver (not using OS)» LED Exampe : boot-ed (microcom)» main.c #incude <config.h> #incude <time.h> #define IEB_LED_CS #define LED_CS x (*((voatie unsigned char *)(IEB_LED_CS))) int main(void) { time_init(); LED_CS = xff; no cache, no optimization Aways Read/Write // Timer Initiaization // LED a off /* 8-Line BUS LEDs Contro */ whie() { LED_CS = xee; mdeay(); // sec LED_CS = xdd; mdeay(); LED_CS = xbb; mdeay(); LED_CS = x77; mdeay(); * I/O Write unsigned char *addr; addr = (unsigned char *)(x); *addr = xaa; * I/O Read unsigned char *addr, char ch; addr = (unsigned char *)(x); ch = *addr; -

22 Test run Fash fusing». Jtag u./jfashmm pxa7x3.dat edtest». boot monitor u u u cp edtest /tftpboot tftp edtest oader (target) fash oader Previous boot-ed (edtest) exampe» MMU is not used mmap() system ca uses MMU» POSIX-compiant system ca : man mmap» Mapping fies or devices into memory» Mapping physica RAM to virtua memory» Used in memory-mapped fie I/O -

23 Physica Address #define ADDRESSDOT x8 #define ADDRESSDOT x9 #define ADDRESSDOT3 xa #define ADDRESSDOT xb #define ADDRESSDOT xc mmap Device driver (using OS with system ca-mmap)» Dot Matrix Exampe : dot (microcom) Virtua Address ped = mmap(null,,prot_write,map_shared,fd,addressdot); Co ped = mmap(null,,prot_write,map_shared,fd,addressdot); Co ped3 = mmap(null,,prot_write,map_shared,fd,addressdot3); Co3 ped = mmap(null,,prot_write,map_shared,fd,addressdot); Co ped = mmap(null,,prot_write,map_shared,fd,addressdot); Co Row7 : data[6] Row6 : data[] Row : data[] Row : data[3] Row3 : data[] Row : data[] Row : data[] * Common cathode * : off / : on Refer to side #6 Number Co : x8 7F Co : x9 Co3 : xa Co : xb Co : xc 7F -3

24 mmap (main.c) unsigned char dot_co[] = {; // Dot Data #define ADDRESSDOT x8 #define ADDRESSDOT x9 #define ADDRESSDOT3 xa #define ADDRESSDOT xb #define ADDRESSDOT xc unsigned short *ped; unsigned short *ped; unsigned short *ped3; unsigned short *ped; unsigned short *ped; void dot_init(void); void dot_reset(void); void asc_to_dot(int); int main() { int count, unsigned int fd; if ((fd=open("/dev/mem",o_rdwr O_SYNC)) < ){ perror("mem open fai\n"); exit(); dot_init(); dot_reset(); for(count = ; count <= 9; count++){ // number 9 dispay asc_to_dot(count); *ped = dot_co[]; Co *ped = dot_co[]; Co *ped3 = dot_co[]; Co3 *ped = dot_co[3]; Co *ped = dot_co[]; Co seep(); return ; -

25 mmap void dot_init(void) { ped = mmap(null,,prot_write,map_shared,fd,addressdot); ped = mmap(null,,prot_write,map_shared,fd,addressdot); ped3 = mmap(null,,prot_write,map_shared,fd,addressdot3); ped = mmap(null,,prot_write,map_shared,fd,addressdot); ped = mmap(null,,prot_write,map_shared,fd,addressdot); return; void dot_reset(void){ // DOT Matrix Cear *ped = x; *ped = x; *ped3 = x; *ped = x; *ped = x; return; // Conversion from ASCII to DOT Data void asc_to_dot(int asc){ switch( asc){ case : dot_co[] = x7f; dot_co[] = x; dot_co[] = x; dot_co[3] = x; dot_co[] = x7f; break; case : dot_co[] = x; dot_co[] = x; dot_co[] = x7f; dot_co[3] = x; dot_co[] = x; break; case : dot_co[] = xf; dot_co[] = x9; dot_co[] = x9; dot_co[3] = x9; dot_co[] = x79; break; case 3 : dot_co[] = x9; dot_co[] = x9; dot_co[] = x9; dot_co[3] = x9; dot_co[] = x7f; break; case : dot_co[] = x78; dot_co[] = x8; dot_co[] = x7f; dot_co[3] = x8; dot_co[] = x8; break; case : dot_co[] = x79; dot_co[] = x9; dot_co[] = x9; dot_co[3] = x9; dot_co[] = xf; break; case 6 : dot_co[] = x7f; dot_co[] = x9; dot_co[] = x9; dot_co[3] = x9; dot_co[] = xf; break; case 7 : dot_co[] = x; dot_co[] = x; dot_co[] = x; dot_co[3] = x; dot_co[] = x7f; break; case 8 : dot_co[] = x7f; dot_co[] = x9; dot_co[] = x9; dot_co[3] = x9; dot_co[] = x7f; break; case 9 : dot_co[] = x78; dot_co[] = x8; dot_co[] = x8; dot_co[3] = x8; dot_co[] = x7f; break; return;» Test run : #./dot -

26 Device driver Device driver (using Modue-LKM)» FND (7-segment) Exampe : fnd (microcom) VCC GND -6

27 Address Mapping data 367 x x x x3 x x x6 x7-7

28 Address Mapping #define FND_MAJOR 3 #define FND_NAME "fnd" #define MAX_FND 8 #define FPGA_FND_CS (x) #define FPGA_FND_CS (x) #define FPGA_FND_CS (x) #define FPGA_FND_CS3 (x3) #define FPGA_FND_CS (x) #define FPGA_FND_CS (x) #define FPGA_FND_CS6 (x6) #define FPGA_FND_CS7 (x7) fnd.c mem_addr_fnd = FPGA_FND_CS; mem_addr_fnd = FPGA_FND_CS; mem_addr_fnd = FPGA_FND_CS; mem_addr_fnd3 = FPGA_FND_CS3; mem_addr_fnd = FPGA_FND_CS; mem_addr_fnd = FPGA_FND_CS; mem_addr_fnd6 = FPGA_FND_CS6; mem_addr_fnd7 = FPGA_FND_CS7; mem_en = x; mem_fnd_cs = ioremap_nocache ( mem_addr_fnd, mem_en); if(!mem_fnd_cs) { printk("error mapping fnd memory"); return -EBUSY; #define FND_CS #define FND_CS #define FND_CS #define FND_CS3 #define FND_CS #define FND_CS #define FND_CS6 #define FND_CS7 (*((voatie unsigned char *)(mem_fnd_cs))) (*((voatie unsigned char *)(mem_fnd_cs))) (*((voatie unsigned char *)(mem_fnd_cs))) (*((voatie unsigned char *)(mem_fnd_cs3))) (*((voatie unsigned char *)(mem_fnd_cs))) (*((voatie unsigned char *)(mem_fnd_cs))) (*((voatie unsigned char *)(mem_fnd_cs6))) (*((voatie unsigned char *)(mem_fnd_cs7))) -8

29 Address Mapping ioremap / iounmap» Remap an arbitrary physica address space into the kerne virtua address space» Virtua address = ioremap_nocache (physica address, size) u /pxa7/kerne/inux-.6.-h7-tku_v./incude/ asm-arm/io.h #define ioremap_nocache(cookie, size) ioremap(cookie, size,, ) u /pxa7/kerne/inux-.6.-h7-tku_v./arch/ arm/mm/ioremap.c ioremap(unsigned ong phys_addr, size_t size, unsigned ong fags, unsigned ong aign) -9

30 System Memory Copy copy_from_user = get_user output device(write)» Copy a memory bock to kerne memory from user memory» Copy_from_user(kerne, user, count) u u /pxa7/kerne/inux-.6.-h7-tku_v./incude /asm-arm/uaccess.h copy_from_user(void *to, const void user *from, unsigned ong n); /pxa7/kerne/inux-.6.-h7-tku_v./arch/ arm/ib/uaccess.s arch_copy_from_user(void *to, const void *from, unsigned ong n); to - kerne memory from - user memory n - number of bytes to copy copy_to_user = put_user input device(read)» Copy a memory bock to user memory from kerne memory -3

31 Bit Position a f FND g b fnd-test.c unsigned char asc_to_fnd(int n){ unsigned char c; e d a : data[] b : data[] c : data[] d : data[3] e : data[] f : data[] g : data[6] dp : data[7] F 3 c dp switch (n) { case : c = x3f; break; case : c = x6; break; case : c = xb; break; case 3: c = xf; break; case : c = x66; break; case : c = x6d; break; case 6: c = x7d; break; case 7: c = x7; break; case 8: c = x7f; break; case 9: c = x67; break; defaut: c = x; break; return c; -3

32 FND Device Driver Device Driver : fnd.c static struct fie_operations device_fops = {.open = fnd_open,.write = fnd_write,.reease = fnd_reease,.ioct = fnd_ioct, ; fnd_open» fnd_cear() -> a off (FND_CS = x;), return fnd_reease : cose» return : reease fie object fnd_write» copy_from_user(disp, buf, count); buf(user), disp(kerne)» number write (case : FND_CS7 = disp[]; break;) -3

33 FND Device Driver fnd_write fnd.c fnd_write (struct fie *fip, const char *buf, size_t count, off_t *f_pos) { int i; write(dev, buf, MAXFND); copy_from_user( disp, buf, count) ; static unsigned char disp[8] = {, buf, count=maxfnd=8 ; buf = user / disp= kerne for(i =; i <= MAX_FND; i++){ switch(i) ; at first ca, a dispay -> disp[] ~ disp[7] = { ; at second ca, a dispay -> disp[] ~ disp[7] = case : FND_CS7 = disp[]; break; case : FND_CS6 = disp[]; break; case 3: FND_CS = disp[]; break; case : FND_CS = disp[3]; break; case : FND_CS3 = disp[]; break; case 6: FND_CS = disp[]; break; case 7: FND_CS = disp[6]; break; case 8: FND_CS = disp[7]; break; defaut : break; return ; -33

34 FND Device Driver fnd_ioct» command process, but do nothing in this case modue_init : fnd_init» register_chrdev» memory mapping : ioremap modue_exit : fnd_exit» unregister_chrdev» memory unmapping : iounmap -3

35 FND Test Program fnd-test.c main(int ac, char *av[]) { int n, count, dev; unsigned char buf[maxfnd+]; MAXFND = 8 dev = open( fnd_dev, O_RDWR); /dev/fnd if (dev < ) { fprintf(stderr, "cannot open FND (%d)", dev); exit(); memset(buf,, sizeof(buf)); for (n = ; n <= 9; n++) { for( count = ; count < MAXFND; count++){ buf[count]= asc_to_fnd(n); buf[] ~ buf[7] = write(dev, buf,maxfnd); useep(); HDD Root fiesystem Memory zimage.edit fnd_test.c fnd.c fnd_test fnd.ko make.cross compie 3.minicom(Zmodem) test fnd.ko 6../fnd_test /dev/fnd.insmod fnd_test.mknod fnd.ko -3

36 Modue Insta/Remove Driver Modue (fnd.ko) Kerne she insmod fnd.ko 커널내함수 Device Driver 배열구조체구조체함수포인터커널함수호츌 fnd.c Init_modue() { register_chrdev(major, fnd,fnd_fops ) fnd_fops fnd_open fnd_reease fnd_write fnd_read fnd_open {kerne function ca or return fnd_reease {kerne function ca or return register_chrdev() (3, * name, *fops) { MAJOR = : chrdevs[] auto assign kerne function ca() { kerne function ca() { device_struct &fnd_fops chrdevs[] MAJOR 데이터포인터 fnd_write { copy_from_user() copy_from_user() { 구조체할당 rmmod fnd fnd_read { copy_to_user() ceanup_modue() { unregister_chrdev(major, fnd ) copy_to_user() { unregister_chrdev(major, * name) { -36

37 Test run Compie modue (o:., ko:.6) : make Downoad to target : minicom / nfs Insta the modue #insmod fnd.ko : /etc/rc.sysinit» Adding a new driver at modue initiaization u int register_chrdev(unsigned int major, const char *name, struct fie_operations *fops);» Remove modue u int unregister_chrdev(unsigned int major, const char *name); List the modue #smod If you et the system pick Major number, you can find the major number (for specia creation) by #more /proc/devices Make a specia fie node character device fie #mknod /dev/fnd c 3-37

38 Appication program #./fnd-test Target booting :» /etc/rc.sysinit : modue oad # ieb modue insmod /data/ccd.ko insmod /data/dc_motor.ko insmod /data/dot.ko insmod /data/fnd.ko insmod /data/key.ko insmod /data/ed.ko insmod /data/st_motor.ko -38

39 LCD LCD Interface Pin No Name Function Description Vss Power GND Vdd Power + V Vss Vdd Vee RS R/W E D D D D3 D D D6 D7 3 Vee Contrast Adj. RS Command R/W Command - V Register Seect contro data Read / Write write read 6 E Command Enabe (Strobe) 7 D I/O Data LSB 8 D I/O Data 9 D I/O Data D3 I/O Data D I/O Data D I/O Data. Direct Contro or Address decoder Contro. bit or 8bit Data Length 3 D6 I/O Data D7 I/O Data MSB -39

40 LCD Instructions Instruction RS RW D7 D6 D D D3 D D D Description time NOP No Operation Cear Dispay Cursor Home x Entry Mode Set I/D S Dispay Contro D C B Cear dispay & set address counter to zero Set adress counter to zero, return shifted dispay to origina position. DD RAM contents remains unchanged. Set cursor move direction (I/D) and specify automatic dispay shift (S). Turn dispay (D), cursor on/off (C), and cursor binking (B)..ms.ms 37us 37us Cursor / Dispay shift S/ C R/ L x x Shift dispay or move cursor (S/C) and specify direction (R/L). 37us Function Set DL N F x x Set CGRAM Address Set DDRAM Address Busy Fag & Address CGRAM Address DDRAM Address BF Address Counter Set interface data width (DL), number of dispay ines (N) and character font (F). Set CGRAM address. CGRAM data is sent afterwards. Set DDRAM address. DDRAM data is sent afterwards. Read busy fag (BF) and address counter 37us 37us 37us Write Data Data Write data into DDRAM or CGRAM 37us Read Data Data Read data from DDRAM or CGRAM 37us -

41 LCD Bit Settings Bit name Settings I/D = Decrement cursor position = Increment cursor position S = No dispay shift = Dispay shift D = Dispay off = Dispay on C = Cursor off = Cursor on B = Cursor bink off = Cursor bink on S/C = Move cursor = Shift dispay R/L = Shift eft = Shift right DL = -bit interface = 8-bit interface N = ine = ines F = x7 dots = x dots BF = Can accept instruction = Interna operation in progress x Don t care DDRAM : Dispay Data RAM CGRAM : Character Generator RAM -

42 - LCD DDRAM DDRAM address usage for a -ine LCD Dispay size Visibe Character positions DDRAM addresses x 6.. h..fh + h..fh x..9 h..3h + h..3h x..3 h..7h + h..7h x 3..3 h..fh + h..fh x..39 h..7h + h..67h. Character position (dec). Row(Line ) DDRAM address (hex) 3. Row(Line ) DDRAM address (hex) A B C D E F A B C D E F A B C D E F A B C D E F

43 LCD Time cyce Write-Cyce V DD.7-.V.-.V.7-.V.-.V Parameter Symbo Min Max Unit Enabe Cyce Time t c - - ns Enabe Puse Width (High) t w ns Enabe Rise/Fa Time t r, t f - - ns Address Setup Time t as ns Address Hod Time t ah - - ns Data Setup Time t ds ns Data Hod Time t h - - ns -3

44 LCD Contro methods» Direct contro : digita I/O (GPIO)» Address decoder contro : I/O address Address decode» Refer to side #» Contro : x3 RS=BA9= (contro) R/W=BA8= (write) mem_base_wr» Data : x38 RS=BA9= (data) R/W=BA8= (write) mem_base_rs -

45 Device Driver LCD device driver : ccd.c» 8 Bit Write [ D~D7 ]» Contro Address = x3, Data Address = x38 #define FPGA_CLCD_WR_ADD (x3) #define FPGA_CLCD_RS_ADD (x38) mem_addr_wr = FPGA_CLCD_WR_ADD; mem_addr_rs = FPGA_CLCD_RS_ADD; mem_base_wr = ioremap_nocache ( mem_addr_wr, mem_en); // modue_init() mem_base_rs = ioremap_nocache ( mem_addr_rs, mem_en); ccd_write static struct fie_operations ccd_fops = {.write = ccd_write,.ioct = ccd_ioct,.open = ccd_open,.reease = ccd_reease, ; static ssize_t ccd_write (struct fie *fip, const char *buf, size_t count, off_t *f_pos) { char data[3]; memset(data,, 3); copy_from_user(data, buf, count); //buf(user), data(kerne) string_out(data); return ; -

46 Device Driver string_out(data); static void string_out(char *str) { char *s; int i=; printk("ccd.o: %s\n", str); cd_init(); for (s=str; *s; s++){ *((voatie unsigned char *)(mem_base_rs)) = *s; // CLCD_DATA_ADDR = *s; if(i == ) { udeay(); *((voatie unsigned char *)(mem_base_wr)) = xc; //Set DDRAM Address to nd ine C = 8 + udeay(); i++; -6

47 Device Driver cd_init(); static void cd_init(void) { *((voatie unsigned char *)(mem_base_wr)) = x38; // Function Set : DL = -bit interface = 8-bit interface N = ine = ines F = x7 dots = x dots mdeay(); *((voatie unsigned char *)(mem_base_wr)) = x38; mdeay(); *((voatie unsigned char *)(mem_base_wr)) = x38; mdeay(); *((voatie unsigned char *)(mem_base_wr)) = xe; mdeay(); // Dispay Contro : D = Dispay off = Dispay on C = Cursor off = Cursor on B = Cursor bink off = Cursor bink on *((voatie unsigned char *)(mem_base_wr)) = x; // Cursor home mdeay(); *((voatie unsigned char *)(mem_base_wr)) = x; // Cear dispay mdeay(); -7

48 Device Driver ccd_open» return ccd_reease» return : reease fie object ccd_ioct» command process static int ccd_ioct( struct fie *fip, unsigned int cmd, unsigned ong arg) { switch(cmd) { case : { string_out("ioct() cmd test "); break; defaut: return ; return ; -8

49 Device Driver modue_init : ccd_init» register_chrdev» memory mapping : ioremap modue_exit : ccd_exit» unregister_chrdev» memory unmapping : iounmap -9

50 Device Driver ccd-test.c Test Program /* LCD test program */ #incude <stdio.h> #incude <fcnt.h> static char cddev[] = "/dev/ccd"; static int cdfd = (-); #define MAXCHR 3 main(int ac, char *av[]) { int n; char buf[maxchr]; cdfd = open( cddev, O_RDWR); if (cdfd < ) { fprintf(stderr, "cannot open LCD (%d)", cdfd); exit(); // ioct(cdfd,, ); // seep(); memset(buf,, sizeof(buf)); if (ac > ) { n = stren(av[]); // av[] = ccd-test, av[]= xxxxx if (n > MAXCHR) n = MAXCHR; // truncate max 3 char above. memcpy(buf, av[], n); write(cdfd, buf, MAXCHR); -

51 Test run Make modue :» sampe modues in microcom homepage Load the modue» insmod ccd.ko : aready instaed at /etc/rc.sysinit, >rmmod ccd Check that the modue is oaded» cat /proc/modues or smod Make specia fie» mknod /dev/ccd c xxx Test run»./ccd-test test message Remove the modue» rmmod ccd -