Hi,
  I've just assembled my new Wisp628 programmer. The programmer itself seems
to work fine, but if I connect an LCD (HD44780A00 driver) to the PIC, Xwisp
reports the following errors:

philpem@aquarius:~/pic_code$ python xwisp.py target 16f628 go lcdtest.hex
XWisp 1.08, command line mode
hardware: Wisp628 1.09 (fast)
target confirmed: 16f628, revision 00
write Code 0000Traceback (most recent call last):
  File "/usr/local/bin/xwisp.py", line 3563, in ?
    XWisp_Main()
  File "/usr/local/bin/xwisp.py", line 3560, in XWisp_Main
    Wisp_Line().Interpret()
  File "/usr/local/bin/xwisp.py", line 3180, in Interpret
    self.Execute( Command )
  File "/usr/local/bin/xwisp.py", line 3162, in Execute
    exec( 'self.CMD_' + Command.upper() + '()' )
  File "<string>", line 1, in ?
  File "/usr/local/bin/xwisp.py", line 2595, in CMD_GO
    Regions = self.Selection )
  File "/usr/local/bin/xwisp.py", line 2250, in Write_Verify
    self.Write( Image, [ Region ], Warn = ( Region == Region_Fuses ) )
  File "/usr/local/bin/xwisp.py", line 2163, in Write
    self.Put( Address, Image.Get( Address ))
  File "/usr/local/bin/xwisp.py", line 2048, in Put
    self.Bus.Send_Expect(( '%04X' % Data ) + 'w' )
  File "/usr/local/bin/xwisp.py", line 915, in Send_Expect
    raise self.WBus_Protocol_Error, \
__main__.WBus_Protocol_Error: send='2829w' received='2829?'

The pin assignments are:
  RB0      Power switch, active low
  RA0      LCD "E"
  RB1      LCD "RS"
  RB2      LCD D4
  RB3      LCD D5
  RB4      LCD D6
  RB5      LCD D7
  RB6      TMR1 osc xtal (32kHz)
  RB7      TMR1 osc xtal (32kHz)

The config word from the source file is:
__CONFIG _INTRC_OSC_NOCLKOUT & _BODEN_OFF & _CP_OFF & _DATA_CP_OFF &
         _PWRTE_ON & _WDT_OFF & _LVP_OFF & _MCLRE_ON
  So, basically, the chip is running off the internal oscillator, with the
brownout detector, code and data protection off, powerup timer on, WDT off,
LVP programming disabled and MCLRE on.

  Strangely enough, if I disconnect RB4 from the LCD, the PIC will program,
read and erase fine. However, as soon as I reconnect RB4, the PIC refuses to
enter program mode. According to Xwisp, the PICs are 16F628s, silicon
revision 00. Now, according to the "PIC16F62X Silicon Errata" from Microchip,
as soon as LVP is disabled, RB4/PGM is ignored. So why the heck is my PIC
refusing to enter program mode if RB4 is connected to the LCD?

Thanks.
--
Phil.                              | Acorn Risc PC600 Mk3, SA202, 64MB, 6GB,
philpem@dsl.pipex.com              | ViewFinder, Ethernet (Acorn AEH62),
http://www.philpem.dsl.pipex.com/  | 8xCD, framegrabber, Teletext
Think "honk" if you're a telepath.

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