From: andrew.mcmeikan@mitswa.com.au
Sent: Tuesday, September 21, 1999 5:00 PM
To: eplus1@san.rr.com
Subject: Re: send file thprn.asm
;be carefull when assembling
;there is a lookup table that MUST NOT cross a
;256 byte boundry ---- CHECK IT
LIST P=16C84, F=INHX8M
;thermal printer controler
innerloop = 0ff
lilloop = 01
bigloop =0ff
strobe macro bt
bsf 0x13,bt ;bit for strobe
bcf 0b,7 ;dont want interupts
call outsr ;clock it out
call lildly ;let it burn in
bsf 0b,7 ;re-enable interupts
bcf 0x13,bt ;so next outsr clears it
endm
ORG 0x0000
GOTO main
ORG 0x0004
;entry occurs in here when host pulls strobe signal low
;to indicate data that requires printing
;useing this int routine occupies two levels of stack
;one for the return address and one for outsr's return
;centronics pinouts
; pin 1 strobe is connected to RB0
; pin 2 data1 " " RA1
; pin 3 data2 " " RA2
; pin 4 data3 " " RA3
; pin 5 data4 " " RA4
; pin 6 data5 " " RB1
; pin 7 data6 " " RB2
; pin 8 data7 " " RB3
; pin 9 data8 " " RB4
; pin10 ack " " Cap from BSY this dips low
; when want next byte
; pin11 busy is connected to RA0 High= offline
; pin12 Paper out is connected to photocell High=no paper
;pins 19 to 30 are signal grounds GND
; pin31 INT is connected to RESET (via diode)
; and is used to initialize printer
movwf 0c ;save 'W' in reg file 0c
swapf 3,w ;grab the flags
movwf 0d ;in reg 'd'
;should now be safe to continue!
bsf 5,0 ;say we are busy
;read both ports to get byte of data
rrf 5,w ;read port a shifting data down one
andlw 0f ;only keep bottom bits
movwf 0x16 ;keep incomming data here
rrf 6,w ;read port b shifting down one
andlw 0f ;wipe out extraneous bits
movwf 0x17 ;waste another register
swapf 0x17,w ;get 'b' data lower into upper W
iorwf 0x16,f ;or top bits into data
;bit pattern from host now in 0x16
incf 0e,f ;increment our count of bytes
;clock data into thermal head
movlw 08 ;for 8 bits
movwf 0x17 ;better keep count of it
clkhd: rlf 0x16,f ;rotate it thru carry
bsf 0x12,4 ;set data high
btfss 3,0 ;check the carry flag
bcf 0x12,4 ;clear data if required
call outsr
bsf 0x12,5 ;clock that bit in
call outsr
bcf 0x12,5 ;drop clock again
call outsr
decfsz 0x17,f ;have we finished loop yet ?
goto clkhd ;guess not
;no point doing the extra shift as we are just
;throwing the data away once it is in the head
;if byte count=max then lets latch and let the main routine
; print it
movlw 0xc0 ;try 192 ;216 max bytes per line 1728 bits
subwf 0e,w ;check max against our byte count
btfss 3,2 ;the same? result of zero?
goto continue ;no its ok, head not full yet
;need to latch thermal head
; We do not not lower busy here
;as main routine will do so once it has reset
;the counter.
bsf 0x12,6 ;latch bit for thermal head
call outsr ;send- no one else better be using it
bcf 0x12,6 ;put back
call outsr ;send that to
goto exint ;leave int handler
continue: ;tell host we are no longer busy, get next byte
bcf 5,0 ;bring BSY low
;and fall thru to exit :)
exint: ;now restore to before interupt
swapf 0d,w ;put flags back in order in W
movwf 3 ;stickem bick in flags
swapf 0c,f ;flip saved W
swapf 0c,w ;flip it back into W
bcf 0b,1 ;clear INTF flag so we can get more
RETFIE
main ;thermal printer control program 192 dpi 9 inch 1728 pixels
;need to set up direction bits for ports
;and set initial pin levels
movlw 0 ;pullups and interrupt on neg edge
option ;set options
movlw 0ff
movf 5,f ;set all pins high on port a
movlw 0fe ;RA0 as output
tris 5 ;porta as input except RA0
movlw 01f ;make bits 6,7 &5 low
movf 6,f
movlw 01f ;port b 5,6,7 as output
tris 6 ;make it so !
movlw 08 ;specify which phase to start on
movwf 0x15 ;store it somewhere safe
clrf 0e ;zero byte count for head
movlw 00 ;phases off clk,lat,data, strb off
movwf 0x12 ;data for shift reg 1
movlw 00 ;all strobes off (low)
movwf 0x13 ;data for shift reg 2
call outsr ;set all pins high except for stepper
movlw 0x90 ;enable RB0 and GIE interupt bits
movwf 0b ;interupts now turned on!
bcf 5,0 ;say we are not busy
p1=8;9 ;1
p2=4;8 ;3 ;ok here are definitions of how the shift registers are wired
p3=2;0c;2 ; ok on 0x12 bit0 stepper phase A
p4=1;4 ;6 ; bit1 " " B
p5=8;6 ;4 ; bit2 " " C
p6=4;2 ;0c ; bit3 " " D
p7=2;3 ;8 ; bit4 Data for thermal head
p8=1;1 ;9 ; bit5 Clock for thermal Head
; bit6 Latch for thermal head
; bit7 strobe 1 for thermal head
; 0x13 bit0 to bit7 rest of strobes for head
mloop: ;this is the loopy bit of main
;we sit in here till we get a full head
;then we reset the counter, send an ack to the host
;print the line out and advance the paper, then we sit until
;the head is full again :)
;first check if the head is full
movlw 0xc0 ;try 192 ;216 max bytes per line 1728 bits
subwf 0e,w ;check max against our byte count
btfss 3,2 ;the same? result of zero?
goto mloop ;no not yet keep waiting
clrf 0e ;Ok we've spotted the head full
;need to strobe head drivers
bsf 0x12,7 ;strb1
bcf 0xb,7 ;turn off interupts
call outsr ;Fire!
call lildly ;let it burn!
bsf 0b,7 ;re-enable interupts
bcf 0x12,7 ;ok thats done
strobe 0
strobe 1
strobe 2
strobe 3
strobe 4
strobe 5
strobe 6
strobe 7
bcf 0b,7 ;turn off interupts
call outsr ;yay! all strobes Fired!
bcf 5,0 ;ok we aren't busy any more
bsf 0b,7 ;re-enable interupts
call papadv ;move paper on to next line
goto mloop ;lets go back and see if another
;line is ready yet
phlook: ;this routine looks up the value for a particular phase
;important that this lookup resides within a 256 byte block
;as PCL is directly modified. if called with value grater
;than 8 ,will cause who knows what kind of crash!
addwf 02,f ;ok now its going to jump :)
nop ;err dont expect zero ?!?!
retlw p8 ;return with phase 8
retlw p7 ;coz we are counting down
retlw p6 ;remember... see next routine!
retlw p5
retlw p4
retlw p3
retlw p2
retlw p1
sleep ;coz its all gone wrong if it
;gets here or past!
;check the listing to be sure
;it fits between page boundries!
papadv: ;this routine is to activate a paper advance one step
;it will use register #15 to keep track of which
;point in the phase cycle it is
movlw 0f0 ;prep mask
bcf 0b,7 ;diable interupts
andwf 0x12,f ;nock off bottom bits
movf 0x15,w ;grab our phase number into W
call phlook
iorwf 0x12,f ;new pattern now set
bsf 0b,7 ;ints re-enabled
decf 0x15,f ;get next phase number
btfsc 3,2 ;did we hit zero?
goto recount ;yep need to reload the counter
bcf 0b,7 ;turn off interupts coz of (outsr)
call outsr ;jump to out put new phase
bsf 0b,7 ;turn on interupts again
return ;and go back
recount: movlw 08 ;we hit zero reset it back to 8
movwf 0x15 ;use it next time round
bcf 0b,7 ;clear interupt enable
call outsr ;I know its just below us
bsf 0b,7 ;but tis only way to keep
return ;the interupts rightly enabled
outsr: ;this routine takes bytes at 0x12 and 0x13
;and clocks them out onto the shift registers
;shift registers accessed on port b bits 5,6 & 7
;bit 6 as clock - clocks data on POSITIVE edge
;bit 7 as data - non inverted
;bit 5 as strobe - latches data on NEGATIVE edge
; we are sending lsb first ie bit# 1 on shift register
; output pin #8
; sending byte at address 0x12 first then 0x13
; this puts 0x12 on the last shift register in line
;uses reg # 14 to keep count of bits
;since this code is NON-RE-ENTERENT, do NOT call it
;while interupts are enabled, coz the int handler
;calls this routine to access the thermal head.
movlw 08 ;for 8 bits
movwf 0x14 ;better keep count of it
shiftbits: rrf 0x12,f ;rotate it thru carry
bsf 6,7 ;set data high
btfss 3,0 ;check the carry flag
bcf 6,7 ;clear data if required
bsf 6,6 ;clock that bit in
bcf 6,6 ;drop clock again
decfsz 0x14,f ;have we finished loop yet ?
goto shiftbits ;guess not
rrf 0x12,f ;preserve the data, shift the carry
;now we have finished one byte lets do the other
movlw 08 ;for 8 bits
movwf 0x14 ;better keep count of it
shiftbitsagain: rrf 0x13,f ;rotate it thru carry
bsf 6,7 ;set data high
btfss 3,0 ;check the carry flag
bcf 6,7 ;clear data if required
bsf 6,6 ;clock that bit in
bcf 6,6 ;drop clock again
decfsz 0x14,f ;have we finished loop yet ?
goto shiftbitsagain ;guess not
rrf 0x13,f ;preserve the data, shift the carry
;now we have really finished clocking bits
bsf 6,5 ;bring up the strobe line
bcf 6,5 ;and LATCH it
return ;back to where ever.
lildly movlw lilloop
movwf 0x11
goto reload
bigdly MOVLW bigloop
MOVWF 0x11
reload MOVLW innerloop
MOVWF 0x10
inloop NOP
DECFSZ 0x10 , f
GOTO inloop
DECFSZ 0x11 , f
GOTO reload
RETURN
ORG 0X2000
DATA 00
DATA 00
DATA 00
DATA 00
ORG 0x2007
DATA 0x19 ;fuse settings
org 0x2100
;data 00
;data 00
;data 00
END
| file: /Techref/microchip/thprn.asm, 15KB, , updated: 1999/9/22 08:55, local time: 2024/11/16 04:36,
|
| | ©2024 These pages are served without commercial sponsorship. (No popup ads, etc...).Bandwidth abuse increases hosting cost forcing sponsorship or shutdown. This server aggressively defends against automated copying for any reason including offline viewing, duplication, etc... Please respect this requirement and DO NOT RIP THIS SITE. Questions?
<A HREF="http://linistepper.com/techref/microchip/thprn.asm"> microchip thprn</A> |
| Did you find what you needed?
|