I just came across this and I am not so sure if this is really working. It is
kind of interesting though.

http://mcubbs.com/bbs/viewthread.php?tid=1561&extra=page%3D1


PS: I think it is better to attach the code since the website is in
Chinese and I believe that the poster is not the authot of
the original source.

Regards,
Xiaofan


http://mcubbs.com/bbs/viewthread.php?tid=1561&extra=page%3D1

TITLE "pp88.asm: serial pic16f88 programmer, @4.0MHz"
LIST p=12F675
ERRORLEVEL 0, -302

; This is a simple and low cost solution for programming the PIC16F88.
; No host software is needed! Just copy the hex file to the serial port.
; (there are some simple rules to be followed see "Limits" below)
;
; RS323 setting is 9600 bps, 8 data bits, no parity, 1 stop bit.
; Programming is not verified; data errors are signalled by a blinking LED.
;
; When a hex file is sent to the programmer the PIC16F88 is completely
; erased and reprogrammed. When the the character 'v' is sent previously
; the PIC is only read and verified against the hexfile.
;
; Programming (linux: cat myfile.hex > /dev/ttyS0)
; -----------
; The LED is off during programming (saves power) and on when complete.
;
; Verifying (linux: echo v > /dev/ttyS0 ; cat myfile.hex > /dev/ttyS0)
; ---------
; The LED is flickering and turned on after successful verification.
;
; Errors
; ------
; LED blinks slowly (2 times/second): hex format or chip verification error.
; LED blinks fastly (4 times/second): receive buffer overrun.
; (the programmer is ready when the LED is blinking: no reset is needed)
; LED remains off: "end of file" missed (socket still powered).
;
; Limits
; ------
; Hex file records must be ordered by ascending addresses with embedded
; configuration at the end. This is normally the case when gpasm is used.
; Records must start on 4 word boundaries (ORG H'..0', ..4, ..8 or ..C).
; EEPROM is erased but not programmed. Only inhx32 format is supported.
;
; Large memory gaps within program code must be avoided (trailing unused
; program memory is no problem). The receive buffer will overrun when too
; many addresses must be skipped. Large gaps are common between program
; code and lookup tables. A possibility to reduce the size of such gaps is
; to define eight words at the beginning of unused 256-word blocks e.g.:
;
; ORG H'0300'
; DT 0,0,0,0,0,0,0,0
;
; Host software or a hexfile converter could also help here, but then
; the programmer is no longer operated without additional software.
;
; * USE AT YOUR OWN RISK * THERE IS ABSOLUTELY NO WARRANTY OF ANY KIND *

; Supply: VPP = 12V (8.5V .. 13.5V; selfpowering from RS232 may work)
;
; +12V >-----+---------------------> +12V
; | -------
; +---| 78L05 |---+-----> +5V
; | ------- |
; 10uF | 10uF
; | | |
; GND ------+-------+-------+------ GND
;
;
; Programmer:
; -------___-------
; | |
; +5V >------------1-|VCC GND|-8------------- GND
; | |
; (PWR) <------------2-|GP5 GP0|-7-----------<> (DAT)
; | |
; GND---LED--470R----3-|GP4 GP1|-6------------> (CLK)
; | |
; RS232 +--4-|GP3 GP2|-5--+ +---< +12V
; (9pin f.) | | PIC12F675 | | |
; +--1 DCD | ----------------- | 4k7
; | 2 TXD 22k | | |
; | 3 RXD >---\/\/\--+-----+ 4k7 +---> (VPP)
; +--4 DTR | | |
; | 5 GND -----------+ --- 4V7 Zehner: | |-
; +--6 DSR | /_\ GP3 has no upper +---| BC107
; 7 RTS --+ | | limitting diode |->
; 8 CTS --+ | | |
; 9 RI +-----+---------------------------+---- GND
;
;
; Target:
; -------___-------
; | |
; 1-|A2 A1|-18
; | |
; 2-|A3 A0|-17
; | |
; 3-|A4 A7|-16
; | |
; (VPP)---------4-|A5 A6|-15
; | |
; GND----------5-|VSS VDD|-14----------(PWR)
; | |
; 6-|B0 B7|-13----------(DAT)
; | |
; 7-|B1 B6|-12----------(CLK)
; | |
; 8-|B2 B5|-11
; | |
; 9-|B3 B4|-10
; | PIC16F88 |
; -----------------
;

__IDLOCS H'BB88' ; the baby's name
__CONFIG H'01C4' ; no CP, BOD, no MCLR, no WDT, internal osc

INDF EQU 0 ; indirect file access
TMR0 EQU 1 ; timer 0
PCL EQU 2 ; program counter lsb
STATUS EQU 3 ; program status
FSR EQU 4 ; file selection register
GPIO EQU 5 ; i/o port
PCLATH EQU H'0A' ; program counter msb
INTCON EQU H'0B' ; interrupt control
PIR1 EQU H'0C' ; peripheral interrupt flags
TMR1L EQU H'0E' ; timer 1 lower byte
TMR1H EQU H'0F' ; timer 1 higher byte
T1CON EQU H'10' ; timer 1 control
CMCON EQU H'19' ; comparator control
ADRESH EQU H'1E' ; most significant ADC bits
ADCON EQU H'1F' ; ad control
_OPTION EQU H'81' ; option register (bank 1)
_TRISIO EQU H'85' ; gpio tristate register (bank 1)
_PIE1 EQU H'8C' ; peripheral interrupt enable (bank 1)
_OSCCAL EQU H'90' ; oscillator calibration (bank 1)
_WPU EQU H'95' ; weak pullup enables (bank 1)
_IOC EQU H'96' ; interrupt on change enables (bank 1)
_VRCON EQU H'99' ; voltage reference control (bank 1)
_EEDATA EQU H'9A' ; eeprom data (bank 1)
_EEADR EQU H'9B' ; eeprom address (bank 1)
_EECON1 EQU H'9C' ; eeprom control (bank 1)
_EECON2 EQU H'9D' ; eeprom control (bank 1)
_ADRESL EQU H'9E' ; least significant ADC bits (bank 1)
_ANSEL EQU H'9F' ; analog select (bank 1)

C EQU 0 ; carry
DC EQU 1 ; digit carry
Z EQU 2 ; zero
PD EQU 3 ; power down
TO EQU 4 ; watch dog time out
RP0 EQU 5 ; register bank select

DAT EQU 0 ; GPIO pins
CLK EQU 1
VPP EQU 2
RXD EQU 3
LED EQU 4
TXD EQU 4
PWR EQU 5

ORG H'20' ; RAM (64 Bytes)
flgs RES 1 ; 7=error 6=blink 3=data 0=verify
scnt RES 1 ; sequence counter
rxsh RES 1 ; receiver shift register
tmp0 RES 1 ; temporary storage
tmp1 RES 1 ; temporary storage
tmp2 RES 1 ; temporary storage
cod0 RES 1 ; ls 7 bits of code data
cod1 RES 1 ; ms 7 bits of code data
pdat RES 1 ; programming write data
pver RES 1 ; programming read data
cmnd RES 1 ; command character
bcnt RES 1 ; byte counter
rtyp RES 1 ; record type
chks RES 1 ; checksum
adrl RES 1 ; address low byte
adrh RES 1 ; address high byte
datl RES 1 ; current word low byte
dath RES 1 ; current word high byte
calo RES 1 ; current address low byte
cahi RES 1 ; current address high byte
malo RES 1 ; memory address low byte
mahi RES 1 ; memory address high byte
rptr RES 1 ; command buffer read pointer
wptr RES 1 ; command buffer write pointer

ORG H'40' ;
buff RES 32 ; command buffer

ORG H'000' ; reset
GOTO main ;

ORG H'010' ;
main CLRF GPIO ;
BSF GPIO,VPP ; VPP off as soon as possible
BSF STATUS,RP0 ; bank 1
MOVLW B'00001000' ; rxd=input, others are outputs
MOVWF _TRISIO ;
CLRF _ANSEL ; all analog pins digital
MOVLW B'11011111' ; no pu, risint, tmr0 iclk, fall, wdt:128
MOVWF _OPTION ;
CALL H'3FF' ; oscillator calibration
MOVWF _OSCCAL ;
BCF STATUS,RP0 ; bank 0
MOVLW B'11111111' ; comparator off
MOVWF CMCON ;
CLRF INTCON ; no interrupts used
CLRF flgs ; clear flags
ppdone MOVLW H'21' ; clear other vars
MOVWF FSR
initvar CLRF 0
INCF FSR,F
MOVLW H'60'
XORWF FSR,W
BTFSS STATUS,Z
GOTO initvar ; end init vars
BSF GPIO,VPP ; VPP off
BCF GPIO,PWR ; PWR off
BSF GPIO,LED ; LED on
RRF flgs,F ; copy error to blink flag
MOVLW H'40' ; and clear other flags
ANDWF flgs,F
loop0 CALL rxbyte ; wait for ':', check for 'v'
MOVWF cmnd
XORLW 'v' ; verify
BTFSC STATUS,Z
BSF flgs,0
MOVF cmnd,W
XORLW ':' ; start
BTFSS STATUS,Z
GOTO loop0 ; rx next byte
prog1 BCF GPIO,LED ; LED off (start programming)
BSF GPIO,PWR ; PWR on
BCF flgs,6 ; clear blink flag
MOVLW B'00110001' ; tmr1: internal clock / 8
MOVWF T1CON ;
MOVLW H'E6' ; initialisation sequence
MOVWF scnt ;
BCF GPIO,VPP ; VPP on (enter programming mode)
BTFSC flgs,0 ; skip erase if verifying
GOTO prog3
MOVLW B'00011111' ; "Chip Erase"
CALL wrbuf
MOVLW B'00101010' ; 10ms delay
CALL wrbuf
GOTO prog3
prog2 CALL rxbyte ; wait for ':'
XORLW ':'
BTFSS STATUS,Z
GOTO prog2
prog3 CLRF chks ; clear checksum
CALL rxnum
MOVWF bcnt ; count
BCF STATUS,C ; count / 2
RRF bcnt,F
CALL rxnum
MOVWF adrh ; address high byte
CALL rxnum
MOVWF adrl ; address low byte
BCF STATUS,C ; adrh:adrl / 2
RRF adrh,F
RRF adrl,F
CALL rxnum
MOVWF rtyp ; record type
DECF rtyp,W ; type == 01 ? (eof)
BTFSC STATUS,Z
GOTO ppend ; ok!
MOVF rtyp,W ; type != 00 ? (unknown)
BTFSS STATUS,Z
GOTO prog2
MOVF bcnt,W ; count == 00 ?
BTFSC STATUS,Z
GOTO prog2
MOVLW B'01100000' ; set address
CALL wrbuf
MOVF adrl,W
CALL wrbuf
MOVF adrh,W
CALL wrbuf
prog4 CALL rxnum
MOVWF datl ; 8 ls bits
CALL rxnum
MOVWF dath ; 6 ms bits
BCF STATUS,C ; shift for start/stop bit
RLF datl,F
RLF dath,F
MOVLW B'10000010' ; "Load Data" when programming
BTFSC flgs,0
MOVLW B'10000100' ; or "Read Data" when verifying
CALL wrbuf
MOVF datl,W ; code word to buff
CALL wrbuf
MOVF dath,W
CALL wrbuf
MOVLW B'10100000' ; increment address
CALL wrbuf
DECFSZ bcnt,F ; all data processed?
GOTO prog4
CALL rxnum ; checksum
MOVF chks,W
BTFSS STATUS,Z
BSF flgs,7 ; blink on checksum error
GOTO prog2
ppend CALL rxbyte ; wait for buf empty
MOVF rptr,W
XORWF wptr,W
BTFSS STATUS,Z
GOTO ppend
GOTO ppdone ; ok: prepare for new job

wrbuf MOVWF tmp0 ; write to buffer
MOVF wptr,W
ADDLW buff
MOVWF FSR
MOVF tmp0,W
MOVWF INDF
INCF wptr,F
BCF wptr,5 ; truncate to < 32
MOVF wptr,W ; check for buffer overrun
XORWF rptr,W
BTFSS STATUS,Z
RETLW 0
BSF flgs,7 ; set blink flag
MOVLW B'00100001' ; tmr1: internal clock / 4
MOVWF T1CON ;
RETLW 0

rdbuf MOVF rptr,W ; command in buffer?
XORWF wptr,W
BTFSC STATUS,Z
RETLW 0 ; buf is empty, Z = 1
MOVF rptr,W
ADDLW buff
MOVWF FSR
MOVF INDF,W
INCF rptr,F
BCF rptr,5 ; truncate to < 32
BCF STATUS,Z
RETURN ; byte available, Z = 0

; pptask: (executed between bit receiving)
; if scnt > 0 decrement scnt and check sequence (-->ppsequ)
; else if ca != ma send increment address command and inc current address
; else if command = B'd00ccccc' command 0ccccc with two databytes if d set
; else if command = B'101xxxxx' inc ma, and "Start Programming" if required
; else if command = B'011xxxxx' set ma to next two bytes from buff
; else if command = B'001xtttt' set scnt to tttt * 8 (delay/endprog)

pptask MOVF scnt,W ; check scnt
BTFSC STATUS,Z
GOTO ppaddr

; sequences:
; 0x7F..0x01 delay and send "End Programming"
; 0x82..0x81 send (or verify) two databytes from buffer
; 0xC5..0xC2 "Load Configuration", 0, 0, ("Begin Erase")
; 0xE6..0xE1 init: delay and send load data 0x01
ppsequ DECF scnt,F ; advance sequence
BTFSS scnt,7 ; <0x7F ? : delay/endprog
GOTO ppwait
ppdata BTFSC scnt,6 ; 0x82 ?
GOTO pplcon
BTFSS scnt,0 ; first byte?
CLRF scnt ; no: done
BTFSC flgs,0 ; read or write?
GOTO ppvery
MOVF rptr,W ; inline rdbuf to save time
ADDLW buff
MOVWF FSR
MOVF INDF,W
INCF rptr,F
BCF rptr,5 ; truncate to < 32
MOVWF pdat
GOTO ppout8
pplcon BTFSC scnt,5 ; 0xC5 ?
GOTO ppinit
CLRF pdat ; "Load Configuration" or data 0
BTFSC scnt,2
GOTO ppout6 ; "Load Configuration"
BTFSC scnt,1
GOTO ppout8 ; data 0 (2 steps)
CLRF scnt ; this is the last step
BTFSC flgs,0 ; verifying: do nothing
RETLW 0
MOVLW D'20' ; delay 2.5ms
MOVWF scnt
MOVLW B'00001000' ; "Begin Erase" for id locations
MOVWF pdat
GOTO ppout6
ppinit MOVF scnt,W
ADDLW H'1D' ; scnt-1 > 0xE2
BTFSC STATUS,C
RETLW 0 ; yes: delay only
BTFSC scnt,1 ; third last?
GOTO ppinld
BTFSC scnt,0 ; second last?
GOTO ppinlo
ppinhi CLRF scnt ; done
CLRF pdat ; msb
GOTO ppout8
ppinlo MOVLW H'02' ; lsb
MOVWF pdat
GOTO ppout8
ppinld MOVLW B'00000010' ; load data 0x01 (see programming spec)
MOVWF pdat
GOTO ppout6
ppwait MOVF scnt,W ; if scnt = 0 send endprog
BTFSS STATUS,Z
RETLW 0
MOVLW B'00010111' ; "End Programming"
MOVWF pdat
GOTO ppout6

ppaddr MOVF calo,W ; compare cahi:calo with mahi:malo
XORWF malo,W
BTFSS STATUS,Z
GOTO ppckpa
MOVF cahi,W
XORWF mahi,W
BTFSS STATUS,Z
GOTO ppckpa
CALL rdbuf ; check buffer
BTFSC STATUS,Z
RETLW 0 ; buf empty
MOVWF pdat
BTFSC pdat,5 ; check if command
GOTO ppinad
MOVLW H'82' ; two databytes if bit 7 set
BTFSC pdat,7
MOVWF scnt
GOTO ppout6 ; sent command

ppinad BTFSS pdat,7 ; '101xxxxx' ?
GOTO ppseta
BSF flgs,3 ; data in this four word block
INCF malo,F ; increment mahi:malo
BTFSC STATUS,Z
INCF mahi,F
ppckpa MOVF malo,W ; check if four addresses done
ANDLW H'03'
BTFSC STATUS,Z
GOTO ppckpr
BTFSS cahi,5 ; or if 0x2008 reached
GOTO ppinca
BTFSS calo,3
GOTO ppinca
ppckpr BTFSC flgs,3 ; program if data changed
GOTO ppprog
BTFSS mahi,5 ; config range requested?
GOTO ppinca
BTFSC cahi,5 ; not yet in config range?
GOTO ppinca
CLRF calo ; set cahi:calo = 0x2000
MOVLW H'20'
MOVWF cahi
MOVLW H'C5' ; set scnt for "Load Configuration"
MOVWF scnt
RETLW 0

ppprog BCF flgs,3 ; clear data change flag
BTFSC flgs,0 ; no programming if verify flag set
RETLW 0
MOVLW D'20' ; delay 2.5ms
MOVWF scnt
MOVLW B'00011000' ; "Begin Program Only"
MOVWF pdat
GOTO ppout6

ppinca INCF calo,F ; increment cahi:calo
BTFSC STATUS,Z
INCF cahi,F
MOVLW B'00000110' ; "Increment Address"
MOVWF pdat
GOTO ppout6

ppseta BTFSS pdat,6 ; 011xxxxx ?
GOTO pptime
CALL rdbuf ; mahi:malo
MOVWF malo
CALL rdbuf
MOVWF mahi
RETLW 0

pptime MOVF pdat,W ; 5 lsb * 8 to scnt
ANDLW H'0F'
MOVWF scnt
BCF STATUS,C
RLF scnt,F
RLF scnt,F
RLF scnt,F
RETLW 0

;;; serial output to pic is linear code to save time
ppout8 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout7 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout6 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout5 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout4 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout3 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout2 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
ppout1 BTFSS pdat,0 ; check bit
BCF GPIO,DAT ; DAT low
BTFSC pdat,0
BSF GPIO,DAT ; DAT high
BSF GPIO,CLK ; CLK high
RRF pdat,F
BCF GPIO,CLK ; CLK low
RETLW 0

ppvery BSF GPIO,LED ; start LED flickering
MOVF rptr,W ; inline rdbuf to save time
ADDLW buff
MOVWF FSR
MOVF INDF,W
INCF rptr,F
BCF rptr,5 ; truncate to < 32
MOVWF pdat
ppverlo BTFSS scnt,0 ; ls byte: tristate data, first bit
GOTO ppver0
BSF STATUS,RP0 ; bank 1
BSF _TRISIO,DAT ;
BCF STATUS,RP0 ; bank 0
BSF GPIO,CLK ; CLK high
BCF STATUS,C
NOP ; ignore data line
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in first bit
ppver0 BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 1
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 2
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 3
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 4
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 5
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 6
BSF GPIO,CLK ; CLK high
BCF STATUS,C
BTFSC GPIO,DAT ; poll data line
BSF STATUS,C
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in data bit 7
ppverhi BTFSC scnt,0 ; ms byte: last bit, drive data
GOTO ppver1
BSF GPIO,CLK ; CLK high
BCF STATUS,C
NOP ; ignore data line
BCF GPIO,CLK ; CLK low
RRF pver,F ; shift in last bit
BSF STATUS,RP0 ; bank 1
BCF _TRISIO,DAT ;
BCF STATUS,RP0 ; bank 0
ppver1 MOVF pver,W ; verify data
XORWF pdat,W
BTFSS STATUS,Z
BSF flgs,7 ; set blink flag
BCF GPIO,LED ; end LED flickering
RETLW 0

blink BTFSS TMR1H,7 ; blink width timer 1
BSF GPIO,LED
BTFSC TMR1H,7
BCF GPIO,LED
RETLW 0

;;; Attention! rxbyte must be called before a new startbit occurs:
;;; --> after receiving a char about 120 cycles are left for other tasks
;;; --> between bit polling pptask executes commands from buff

rxbyte BTFSC GPIO,RXD ; polled receive 9600bps @4MHz
GOTO rxbyte ; wait for idle RX line
rxstrt BTFSC flgs,6 ; blink LED?
CALL blink ;
BTFSS GPIO,RXD ; wait for start bit
GOTO rxstrt ;
CLRF rxsh ;
BSF rxsh,7 ; shift in startbit
MOVLW -D'148' ; set timer to middle of first bit
MOVWF TMR0 ;
rxnext BCF INTCON,2 ; clear timer overflow flag
CALL pptask ; max. 90 cycles !
rxbit BTFSS INTCON,2 ; wait for bit timer
GOTO rxbit ;
MOVLW -D'102' ; set bit timer
ADDWF TMR0,F ;
BCF STATUS,C ; poll rx-line
BTFSS GPIO,RXD ;
BSF STATUS,C ;
RRF rxsh,F ; shift in new bit
BTFSS STATUS,C ; startbit rotated to carry?
GOTO rxnext ;
MOVF rxsh,W ;
RETURN ;

rxhex CALL rxbyte ; receive hex char
BTFSC rxsh,6
ADDLW H'09'
ANDLW H'0F'
RETURN

rxnum CALL rxhex ; receive two digit hex byte
MOVWF tmp1
SWAPF tmp1,F
CALL rxhex
IORWF tmp1,W
ADDWF chks,F ; update checksum
RETURN

END;

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