E' stato elaborato un driver in Assembly per comandare il display
controller TM1637.
La versione proposta è scritta per Enhanced Midrange, ma è facilmente
adeguabile a PIC18F.
Sono utilizzati due pin di un port qualsiasi.
Il driver fornisce le seguenti funzioni:
; TMInit - inizializza
l'I/O necessario al driver (2 pin)
; TMStart - invia uno START al TM1637
; TMStop - invia uno STOP al TM1637
; TMAsk - attende la risposta ASK dal TM1637
; TMWrByte - scrive un byte dal WREG verso il TM1637
; TMWr4Disp - scrive i valori relativi ai 4 display più la luminosità
; TMRdKey - legge il set dei pulsanti, risultato reso in WREG
I ritardi necessari sono sono realizzabili con poche istruzioni, a seconda
del clock del processore oppure con una macro del genere Delayus.
Assieme al file principale delle subroutines esiste un file di intestazione
che va modificato per assegnare i pin desiderati.
I sorgenti.
L'header da modificare a seconda delle assegnazioni hardware:
;************************************************************************
;**
**
;** Title : Pseudo I2C driver for TM1637
**
;** User definition header
**
;** Hardware :
**
;** Processor : PIC Enhanced Midrange
**
;** Date : 8-01-2009
**
;** Version : V.01
**
;** Autore : afg
**
;**
**
;************************************************************************
;** This file defines the microcontroller pin used for TM1637
;** communication and the RAM required for the driver.
;** This file needs to be modified depending on the hardware connection.
;************************************************************************
NOLIST
; 1. - Hardware interface - 2 digital I/O pin on the same port
;========================================================================
;---->>>> Change depending on the hardware connection.
; Control lines of the interface
#define TMCLK LATB,6
#define TMCLKTRIS TRISB,6
#define TMDIO LATB,7
#define TMDIOTRIS TRISB,7
#define TMPORT PORTB
#define TMLAT LATB
#define TMTRIS TRISB
; 2. - Driver required memory: 8 bytes on banked RAM
;========================================================================
TMRAM UDATA
TMTMP res 1 ; variabli
TMTMP1 res 1
TMBUF res 1 ; I2C Communication Register
TMCHR res 4 ; display buffer
TMBRI res 1 ; brightness buffer
;************************************************************************
LIST
Il set di subroutines del driver:
;************************************************************************
;**
**
;** Title : Pseudo I2C driver for
TM1637
**
;** Hardware
:
**
;** Processor : PIC Enhanced Midrange
**
;** Date :
8-01-2009
**
;** Version :
V.01
**
;** Autore : afg
**
;**
**
;************************************************************************
;************************************************************************
; Functions (subroutines):
; TMInit - initialize I/O for TM1637 driver
; TMStart - Send START to TM1637
; TMStop - Send STOP to TM1637
; TMAsk - Wait for ASK from TM1637
; TMWrByte - Write a byte to TM1637
; TMWr4Disp - Write 4 display on TM1637 and add brightness
; TMRdKey - Read key set, result in WREG
;
;************************************************************************
; Note:
;************************************************************************
;************************************************************************
; TMInit - sub - initialize I/O for TMdriver
; clk = 1 , dio = 1
;************************************************************************
TMInit:
GLOBAL TMInit
banksel TMLAT
bsf TMCLK
; preset clk=1
bsf TMDIO
; preset dio=1
banksel TMTRIS
bcf TMCLKTRIS
; clk=out=1
bcf TMDIOTRIS
; dio=out=1
return
;************************************************************************
; TMStart - sub - Send START to TM1637
;************************************************************************
TMStart:
GLOBAL TMStart
banksel TMLAT
bsf TMCLK
; clk=1
bsf TMDIO
; dio=1
Delayus
5 ; Delayus
2
bcf TMDIO
; dio=0
return
;************************************************************************
; TMStop - sub - Send STOP to TM1637
;************************************************************************
TMStop:
GLOBAL TMStop
banksel TMLAT
bcf TMCLK
; clk=0
Delayus
5 ; Delayus
2
banksel TMLAT
bcf TMDIO
; dio=0
Delayus
5 ; Delayus
2
banksel TMLAT
bsf TMCLK
; clk=1
Delayus
5 ; Delayus
2
banksel TMLAT
bsf TMDIO
; dio=1
return
;************************************************************************
; TMAsk - sub - Wait for ASK from TM1637
;************************************************************************
TMAsk:
GLOBAL TMAsk
banksel TMLAT
bcf TMCLK
; clk=0
banksel TMTRIS
bsf TMDIOTRIS
; dio=in
Delayus
5 ; Delayus
2
banksel TMPORT
tmask0 btfsc TMDIO ;
while (dio)
bra tmask0
banksel TMLAT
bcf TMDIO
; preset latch=0
banksel TMTRIS
bcf TMDIOTRIS
; dio=out=0
banksel TMLAT
bsf TMCLK
; clk=1
Delayus
5 ; Delayus
2
banksel TMLAT
bcf TMCLK
; clk=0
return
;************************************************************************
; TMWrByte - sub - Write a byte to TM1637
; Data/command come on WREG
;************************************************************************
TMWrByte:
GLOBAL TMWrByte
banksel TMBUF
movwf TMBUF
; save data
banksel TMTMP
movlw
8 ; cntr = 8
movwf TMTMP
tmwrlp:
banksel TMLAT
bcf TMCLK
; clk=0
Delayus
5 ; Delayus
2
banksel TMBUF
rrf TMBUF,f
; TMBUF = TMBUF >> 1
banksel TMLAT
bsf TMDIO
; dio=1
skpc
; if (TMBUF & 0x01), dio=1
bcf TMDIO
; else (dio=0)
Delayus
5 ; Delayus
3
banksel TMLAT
bsf TMCLK
; clk=1
Delayus
5 ; Delayus
3
banksel TMTMP
decfsz TMTMP,f
; if cntr >0 cntr --
bra tmwrlp
return
;************************************************************************
; TMWr4Disp - sub - Write 4 display on TM1637 and add brightness
; Data/command stored on TMCHAR buffer
; Brightness stored on TMBRI buffer
;************************************************************************
TMWr4Disp:
GLOBAL TMWr4Disp
call TMStart
movlw
0x40 ; auto increment
call TMWrByte
call TMAsk
call TMStop
banksel TMTMP1
movlw
4 ; counter=4
movwf TMTMP1
Delayus
5 ; Delayus
2
call TMStart
movlw
0xC0 ; first addr.
call TMWrByte
call TMAsk
movlw LOW (TMCHR) ; set
indirect pointer
movwf FSR1L
movlw HIGH (TMCHR)
movwf FSR1H
tmwr4lp:
movf INDF1,w
call TMWrByte
call TMAsk
incf FSR1L,f
skpnz
incf FSR1H,f
banksel TMTMP1
decfsz TMTMP1,f
bra tmwr4lp
call TMStop
call TMStart
Delayus
5 ; Delay
5us
banksel TMBRI
movf TMBRI,w
; brightness
call TMWrByte
call TMAsk
call TMStop
return
;************************************************************************
; TMRdKey - sub - Read key set, result in WREG
;************************************************************************
TMRdKey:
GLOBAL TMRdKey
call TMStart
movlw
0x42 ; read button command
call TMWrByte
call TMAsk
banksel TMTRIS
bsf TMDIOTRIS
; dio=input=1
movlw
8 ; cntr = 8
banksel TMTMP
movwf TMTMP
clrf TMBUF
; clear result buffer
tmsklp:
banksel TMLAT
bcf TMCLK
; clk=0
banksel TMBUF
clrc
rrf TMBUF,f
; TMBUF = TMBUF >> 1
Delayus
30 ; delay 30us
banksel TMLAT
bsf TMCLK
; clk=1
banksel TMPORT
btfss TMDIO
; if(dio)
bra tmsk0
banksel TMBUF
; TMBUF = TMBUF|0x80
bsf TMBUF,7
tmsk0 Delayus
30 ; delay 30us
banksel TMTMP
; while cntr >0 cntr --
decfsz TMTMP,f
bra tmsklp
call TMAsk
call TMStop
banksel TMBUF
movf TMBUF,w
return
;************************************************************************
I ritardi inseriti sono tutti da 5us (esclusi quelli da 30us per la lettura
dei contatti).
Questo valore è di ampia sicurezza ed ha permesso il funzionamento i tutte le
condizioni provate. Se si vuole ottenere una maggiore velocità di
trasmissione si possono portare i ritardi a 2 e 3us come indicato nei
commenti.
E' stato elaborato anche un semplice programma di test.
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