|
I'm using a PIC16F627 to hopefully control an Osram SCDQ 4 character,
5x5 matrix display. It uses 5 inputs, being gnd, vcc, sdclk, sdata, and load. I've been trying to set up the 16F627 to use synchronous master serial to send characters to the display, but haven't been successful. I assume that RB2/TX/CK goes to the sdclk pin, RB1/RX/DT goes to the sdata pin. vdd and gnd are obvious, but what about load? I also don't know what the baud rate generator should be set at, as there's no mention in the datasheet for the display. I'm using the internal oscillator on the PIC at 4Mhz. Should RB1 and RB2 be inputs or outputs? Also, as far as I know, to send data to the display I should do the following: Set the BRG: SPBRG = ? Enable the sync master serial port by setting SYNC, SPEN, and CSRC Set TXEN to enable the transmission And start the transmission by loading TXREG What about multiple transmissions? Do I have to watch a flag? |
|
|
LED displays, synchronous serial?
Started by ●September 11, 2003
Reply by ●September 12, 20032003-09-12
|
--- tadaosystems <> escribi > I'm using a PIC16F627 to hopefully control an Osram > SCDQ 4 character, > 5x5 matrix display. > > It uses 5 inputs, being gnd, vcc, sdclk, sdata, and > load. > > I've been trying to set up the 16F627 to use > synchronous master > serial to send characters to the display, but > haven't been successful. > > I assume that RB2/TX/CK goes to the sdclk pin, > RB1/RX/DT goes to the > sdata pin. vdd and gnd are obvious, but what about > load? > > I also don't know what the baud rate generator > should be set at, as > there's no mention in the datasheet for the display. > I'm using the > internal oscillator on the PIC at 4Mhz. > > Should RB1 and RB2 be inputs or outputs? Also, as > far as I know, to > send data to the display I should do the following: > > Set the BRG: SPBRG = ? > Enable the sync master serial port by setting SYNC, > SPEN, and CSRC > Set TXEN to enable the transmission > And start the transmission by loading TXREG > > What about multiple transmissions? Do I have to > watch a flag? > Hello, im using this display without any troubles, but it seems that you are driving the display input signals incorrectly. The Data, SDclk and Ldata pins of the display must be driven by outputs in the pic (you can of course multiplex this pins as inputs but this dont matter the display) the bits of each row of each character needs to be loaded in sync with the sdclk pin transitions, this is eight bits for each row and five rows per character and at the end of each 8 bits gruop (this is each row)the ldata signal needs to be changed of state. in the datasheet there is a timing chart that displays the correct transitions of each signal.The display operates in the range of nanoseconds so a 4 Mhz PIC drives it perfectly without the need of delay loops. An important question is that the SCDQ has no reset pin (the SCDV has)so you MUST send the reset and clear code before anithing else or the display just dont displays nothing!!!! If you are interested i can send the code im use to drive the display. In this code i have included the routines to generate the characters (the display is romless so it comes with no character tables included) I use now the SCDQ5542 and SCDV5542 displays (4characters 5x5 dots each character) but the code is universal you just may need to adjust the address of the character to match your display size.Regards ___________________________________________________ Yahoo! Messenger - Nueva versi GRATIS Super Webcam, voz, caritas animadas, y m... http://messenger.yahoo.es |
|
|
Reply by ●September 13, 20032003-09-13
|
--- In , omar cusce <ocusce@y...> wrote: > Hello, im using this display without any troubles, but > it seems that you are driving the display input > signals incorrectly. > The Data, SDclk and Ldata pins of the display must be > driven by outputs in the pic (you can of course > multiplex this pins as inputs but this dont matter the > display) the bits of each row of each character needs > to be loaded in sync with the sdclk pin transitions, > this is eight bits for each row and five rows per > character and at the end of each 8 bits gruop (this is > each row)the ldata signal needs to be changed of > state. in the datasheet there is a timing chart that > displays the correct transitions of each signal.The > display operates in the range of nanoseconds so a 4 > Mhz PIC drives it perfectly without the need of delay > loops. > An important question is that the SCDQ has no reset > pin (the SCDV has)so you MUST send the reset and clear > code before anithing else or the display just dont > displays nothing!!!! > If you are interested i can send the code im use to > drive the display. In this code i have included the > routines to generate the characters (the display is > romless so it comes with no character tables included) > I use now the SCDQ5542 and SCDV5542 displays > (4characters 5x5 dots each character) but the code is > universal you just may need to adjust the address of > the character to match your display size.Regards > I'm using the SCDQ5542, to be specific. I would VERY much appreciate being able to see your code. Thanks! |
|
|
Reply by ●September 14, 20032003-09-14
|
--- tadaosystems <> escribi > --- In , omar cusce > <ocusce@y...> wrote: Well here goes the code and a gif with the schematic for a 16f86 PIC, feel free to use and modify the code as any other people interested in it and if you can improve it then send me a mail. Just for curiosity, where do yo buy the SCDQ? i ask you because i cant find it anymore here in Argentina and i have taked some displays from old PAIRGAIN hdsl modems. and these displays are fantastic for the 8 pin PICs because it can be drived with only 3 pins! Regards ___________________________________________________ Yahoo! Messenger - Nueva versi GRATIS Super Webcam, voz, caritas animadas, y m... http://messenger.yahoo.es | |||
|
;This program controls a 5 pin ;inteligent display scdq5542 from osram ;the display is driven just with 3 pic lines ;and the connections are: ;pin 1 of display in ra0 (load data enable) ;pin 2 of display in ra1 (data) ;pin 3 of display in ra2 (serial data clock) ; ;-------------------------------- ;NOTE: THIS CODE IS FULLY FUNCTIONAL BUT VERY ROUGH ;SURELLY IT CAN BE IMPROVED AND OPTIMIZED, SPECIALLY THE METHOD TO GET ;THE DATA FOR EACH CHARACTER, SUGESTIONS AND IDEAS ARE WELCOME ;I.E. YOU CAN MODIFY THE CODE TO DRIVE 2 OR MORE DISPLAYS AT THE SAME ;TIME USING THE LDATA PIN TO ENABLE EACH AND THE OTHER SIGNALS IN A BUS ;-------------------------------- LIST PF84A ;tells which processor is used INCLUDE "p16F84A.inc" ;defines various registers etc. Look it over. __CONFIG _PWRTE_ON & _XT_OSC & _WDT_OFF ;config bits ;configured poweron timer and osc cristal ;-------------------------------- ;Set vars CONVERT equ 0ch ;auxiliar for parallel to serial conversion COUNTER equ 0dh ;auxiliar counter COUNT2 equ 0eh ;auxiliar counter 2 CHARPOS equ 0fh ;character position in the display CHAR equ 10h ;character to show LDATA equ 0 ;pin 1 display in ra0 (load data enable) BDATA equ 1 ;pin 2 display in ra1 (data) SDCLK equ 2 ;pin 3 display in ra2 (serial clock) ;-------------------------------- ;Set ports bsf STATUS,RP0 movlw 00h movwf TRISA bcf STATUS,RP0 movlw .255 ;puts all pins 1 for safe movwf PORTA movlw b'11000000' ;initializing the display sending a clear, to do this call Conversion ;loads clear in w and call serial conversion rutine ;-------------------------------- ;begins main loop ;THIS IS JUST AN EXAMPLE, IT DRAWS CONTINUOSLY THE SAME CHARS AND DO NOTHING ;MORE THAN THIS. ;-------------------------------- Start movlw b'10100000' ;char0 address movwf CHARPOS clrf CHAR ;shows first character in table (in this code a 0 number) call Drwchar incf CHARPOS ;char1 address movlw .3 ;shows char 3 in table (the number 3) movwf CHAR call Drwchar incf CHARPOS ;char2 address movlw .10 ;shows char 10 in table (the A letter) movwf CHAR call Drwchar incf CHARPOS ;char3 address movlw .15 ;showsw char 15 in table (the F letter) movwf CHAR call Drwchar goto Start ;End of main loop ;-------------------------------- ;Begin of the paralel to serial routine that drives the display Conversion movwf CONVERT ;takes the data in W and puts in the CONVERT register movlw 08h ;initializes the 8 events counter to make the movwf COUNTER ;conversion of the byte in CONVERT register to serie bcf PORTA,LDATA ;pulls down LDATA enables data write in the display bcf PORTA,SDCLK ;pull down data clock bcf PORTA,BDATA ;puts 0 in output data btfsc CONVERT,0 ;if the bit to transmit was not zero then bsf PORTA,BDATA ;it changes, if it was zero just leaves unchanged bsf PORTA,SDCLK ;pull up data clock, display loads data (just that bit) rrf CONVERT ;rotate CONVERT register to right decfsz COUNTER ;decrements counter, if there is more bits to transmit goto $-7 ;goes back again bsf PORTA,LDATA ;pulls up LDATA, the display shows the data return ;End of conversion routine ;-------------------------------- ;Begin routine that gets data and draws each character (6 bytes) Drwchar movlw .5 ;load counter with number of read cicles movwf COUNT2 ; movf CHARPOS,W ;loads character position in w and send it to the call Conversion ;parallel to serial routine movf CHAR,W ;loads character to be drawed in W bcf STATUS,C ;clear the carry bit rlf CHAR ;multiplies the register CHAR x2 rlf CHAR ;multiplies register CHAR x2 again addwf CHAR,F ;completes multiplication x5 adding CHAR one more time call Dselect ;call routine that load data of characters from tables call Conversion ;and begins to draw into display incf CHAR,F ;increments register CHAR decfsz COUNT2 ;decrements register COUNT2 an exits if zero goto $-4 ;go back to search more data in tables return ;End of data and draw routine ;-------------------------------- ;Begin routine that loads bits to be drawed Dselect movf CHAR,W addwf PCL ;adss w to PCL to get each row of the character ;From here goes the tables that stores the data for each character ;these tables will be readed incrementing in a calculated form the program ;counter, for this reason the practical limit is 49 diferent characters ;this is 49*5 bytes to be read without bank switching Data0 dt b'00001110',b'00110011',b'01010101',b'01111001',b'10001110' Data1 dt b'00000100',b'00101100',b'01000100',b'01100100',b'10001110' Data2 dt b'00001110',b'00110001',b'01000110',b'01101000',b'10011111' Data3 dt b'00011110',b'00100001',b'01001110',b'01100001',b'10011110' Data4 dt b'00000110',b'00101010',b'01011111',b'01100010',b'10000010' Data5 dt b'00011111',b'00110000',b'01011110',b'01100001',b'10011110' Data6 dt b'00000110',b'00101000',b'01011110',b'01110001',b'10001110' Data7 dt b'00011111',b'00100010',b'01000100',b'01101000',b'10001000' Data8 dt b'00001110',b'00110001',b'01001110',b'01110001',b'10001110' Data9 dt b'00001110',b'00110001',b'01001111',b'01100010',b'10001100' DataA dt b'00000100',b'00101010',b'01011111',b'01110001',b'10010001' DataB dt b'00011110',b'00101001',b'01001110',b'01101001',b'10011110' DataC dt b'00001111',b'00110000',b'01010000',b'01110000',b'10001111' DataD dt b'00011110',b'00101001',b'01001001',b'01101001',b'10011110' DataE dt b'00011111',b'00110000',b'01011110',b'01110000',b'10011111' DataF dt b'00011111',b'00110000',b'01011110',b'01110000',b'10010000' DataG dt b'00001111',b'00110000',b'01010011',b'01110001',b'10001111' DataH dt b'00010001',b'00110001',b'01011111',b'01110001',b'10010001' DataI dt b'00001110',b'00100100',b'01000100',b'01100100',b'10001110' DataJ dt b'00000001',b'00100001',b'01000001',b'01110001',b'10001110' DataK dt b'00010011',b'00110100',b'01011000',b'01110100',b'10010011' DataL dt b'00010000',b'00110000',b'01010000',b'01110000',b'10011111' DataM dt b'00010001',b'00111011',b'01010101',b'01110001',b'10010001' DataN dt b'00010001',b'00111001',b'01010101',b'01110011',b'10010001' DataO dt b'00001110',b'00110001',b'01010001',b'01110001',b'10001110' DataP dt b'00011110',b'00110001',b'01011110',b'01110000',b'10010000' DataQ dt b'00001100',b'00110010',b'01010110',b'01110010',b'10001101' DataR dt b'00011110',b'00110001',b'01011110',b'01110100',b'10010010' DataS dt b'00001111',b'00110000',b'01001110',b'01100001',b'10011110' DataT dt b'00011111',b'00100100',b'01000100',b'01100100',b'10000100' DataU dt b'00010001',b'00110001',b'01010001',b'01110001',b'10001110' DataV dt b'00010001',b'00110001',b'01010001',b'01101010',b'10000100' DataW dt b'00010001',b'00110001',b'01010101',b'01111011',b'10010001' DataX dt b'00010001',b'00101010',b'01000100',b'01101010',b'10010001' DataY dt b'00010001',b'00101010',b'01000100',b'01100100',b'10000100' DataZ dt b'00011111',b'00100010',b'01000100',b'01101000',b'10011111' ;End of data tables return ;End of data load routine ;-------------------------------- end | |||
| |||
|
|
Reply by ●September 15, 20032003-09-15
