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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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 Posted: Thu Mar 25, 2021 9:44 am Post subject: I2C LCD PCF8574 Adapter Library |
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'lcd_i2c.LIB' and 'bl_lcd_i2c.LIB' have been re-edited for the commercially available PCF8574 I2C LCD adapter board.
You can control multiple LCDs [up to 8] by changing the slave address of PCF8574.
Software I2C and TWI can be changed by [I2c_select].
Circuit diagram
https://drive.google.com/file/d/16oR1toL40Z3vEJHSHsyoLEHTDxihpRLn/view?usp=sharing
Adapter board
https://drive.google.com/file/d/1abm7OaR63MSxJyDIUDMqgCTbxSpUu5zW/view?usp=sharing
https://drive.google.com/file/d/1iT7vKscLrOTqLwyzkuPIuUcTJFoQGDim/view?usp=sharing
https://drive.google.com/file/d/1Wj1bvnkUgL8jYgW72P1cbYl9sbrN6bTz/view?usp=sharing
| Code: | $programmer = 22 'ARDUINO (using stk500v1 protocol)
'
' **********************************
' * PCF8574 I2C LCD Adapter test *
' * 2021/ 3/24 *
' **********************************
'
$regfile = "m328pdef.dat" 'Set the AVR to use.
$crystal = 16000000 'Set the AVR clock.
'
$hwstack = 64 'Set the capacity of the hardware stack.
$swstack = 10 'Set the capacity of the software stack.
$framesize = 24 'Set the capacity of the frame area.
'
' * PCF8574 I2C LCD Adapter settings *
'
Const I2c_select = 1 '0:Software I2C , 1:TWI
#if I2c_select = 0
'------[For software I2C]------
Config I2cdelay = 10 'SCL clock frequency = approx. 42KHz. (At AVR clock 16MHz) (* Maximum 100KHz)
Config Scl = Portd.2 'Set the port pin to connect the SCL line of the I2C bus.
Config Sda = Portd.3 'Set the port pin to connect the SDA line of the I2C bus.
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#else
'------[For TWI]------------------
$lib "i2c_twi.lib" 'Incorporate the hardware I2C/TWI library.
Config Twi = 100000 'I2C bus clock = 100KHz
Config Scl = Portc.5 'You must specify the SCL pin name.
Config Sda = Portc.4 'You must specify the SDA pin name.
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#endif
Dim Pcf8574_lcd As Byte : Pcf8574_lcd = &H4E 'PCF8574 slave address. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Dim Backlight As Byte : Backlight = 1 'LCD backlight control. (0: off, 1: on)
$lib "lcd_i2c_PCF8574.LIB" 'Incorporate the library of I2C LCD PCF8574 Adapter.
Config Lcd = 20x4 'Set the LCD to 20 characters and 4 lines.
Initlcd 'Initialize the LCD.
'
' ****************
' * Display test *
' ****************
'
Locate 1 , 1 'Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 2 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 'Write the custom character [Lightning] to the LCD.
Locate 1 , 15 'Display custom characters.
Lcd Chr(2) ; "1"
'
Locate 1 , 9 'Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
Wait 3
'
Backlight = 0 'Turn off the LCD backlight.
Locate 1 , 1 'Send a dummy command to control the backlight.
Wait 2
Backlight = 1 'Turn on the LCD backlight.
Locate 1 , 1 'Send a dummy command to control the backlight.
'
Locate 2 , 16 'Display the cursor.
Cursor On , Blink
End |
Last edited by O-Family on Tue May 04, 2021 2:15 am; edited 2 times in total |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Thu Mar 25, 2021 9:52 am Post subject: |
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Multiple LCD codes.
| Code: |
$programmer = 22 'ARDUINO (using stk500v1 protocol)
'
' *************************************
' * PCF8574 I2C LCD Adapter test *
' * For multiple LCDs 2021/ 3/24 *
' *************************************
'
$regfile = "m328pdef.dat" 'Set the AVR to use.
$crystal = 16000000 'Set the AVR clock.
'
$hwstack = 64 'Set the capacity of the hardware stack.
$swstack = 10 'Set the capacity of the software stack.
$framesize = 24 'Set the capacity of the frame area.
'
' * PCF8574 I2C LCD Adapter settings *
'
Const I2c_select = 1 '0:Software I2C , 1:TWI
#if I2c_select = 0
'------[For software I2C]------
Config I2cdelay = 10 'SCL clock frequency = approx. 42KHz. (At AVR clock 16MHz) (* Maximum 100KHz)
Config Scl = Portd.2 'Set the port pin to connect the SCL line of the I2C bus.
Config Sda = Portd.3 'Set the port pin to connect the SDA line of the I2C bus.
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#else
'------[For TWI]------------------
$lib "i2c_twi.lib" 'Incorporate the hardware I2C/TWI library.
Config Twi = 100000 'I2C bus clock = 100KHz
Config Scl = Portc.5 'You must specify the SCL pin name.
Config Sda = Portc.4 'You must specify the SDA pin name.
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#endif
Dim Pcf8574_lcd As Byte : Pcf8574_lcd = &H4E 'PCF8574 slave address. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Dim Backlight As Byte : Backlight = 1 'LCD backlight control. (0: off, 1: on)
$lib "lcd_i2c_PCF8574.LIB" 'Incorporate the library of I2C LCD PCF8574 Adapter.
Config Lcd = 20x4 'Set the LCD to 20 characters and 4 lines.
Initlcd 'Initialize the LCD.
'
' * When installing the second and subsequent LCDs *
'
Pcf8574_lcd = &H4C 'The slave address of the second PCF8574. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Initlcd 'Initialize the second LCD.
'
Pcf8574_lcd = &H4A 'The slave address of the third PCF8574. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Initlcd 'Initialize the third LCD.
'
' ****************
' * Display test *
' ****************
'
Pcf8574_lcd = &H4E 'Specify the first LCD.
'
Locate 1 , 1 'Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 2 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 'Write the custom character [Lightning] to the LCD.
Locate 1 , 15 'Display custom characters.
Lcd Chr(2) ; "1"
'
Locate 1 , 9 'Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
'
' * Second LCD *
'
Pcf8574_lcd = &H4C 'Specify the second LCD.
'
Locate 1 , 1 'Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 3 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 'Write the custom character [Lightning] to the LCD.
Locate 1 , 15 'Display custom characters.
Lcd Chr(3) ; "2"
'
Locate 1 , 9 'Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
'
' * Third LCD *
'
Pcf8574_lcd = &H4A 'Specify the third LCD.
'
Locate 1 , 1 'Display of title.
Lcd "PCF8574"
'
Locate 2 , 4
Lcd "I2C LCD Adapter"
'
Deflcdchar 4 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 'Write the custom character [Lightning] to the LCD.
Locate 1 , 19 'Display custom characters.
Lcd Chr(4) ; "3"
'
Locate 1 , 9 'Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
'
Locate 3 , 3
Lcd "-- 3rd Line --"
'
Locate 4 , 4
Lcd "20x4 Display "
'
Locate 4 , 20 'Display the cursor.
Cursor On , Blink
End
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albertsm
Joined: 09 Apr 2004
Posts: 5921
Location: Holland
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| Posted: Thu Mar 25, 2021 10:36 am Post subject: |
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Hi O-Family,
A fantastic contribution 
Thank you for sharing this. You did the lib as it should have been done.
I will add the lib to the distribution too if you don't mind.
_________________
Mark |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Fri Mar 26, 2021 12:45 am Post subject: |
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Hi,
Hope it helps many users! |
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aphawk
Joined: 23 Jan 2010
Posts: 168
Location: Brazil
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| Posted: Fri Mar 26, 2021 9:25 pm Post subject: |
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Hi,
Only to inform that this new library has ceased all Proteus simulation problem that I have for some years .... now the display works for more than 10 minutes without any problem.
Tried in 3 different projects, all works perfect now !
The old library makes simulation erratic after one or two minutes...
Thanks for all people involved in this actualization !
Paulo |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Tue May 04, 2021 2:19 am Post subject: |
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Fixed a bug when using USI.
Please reload the library.
| Code: |
$programmer = 16 'USBprog Programmer/ AVR ISP mkII (Atmel)
'$prog &HFF , &H62 , &HDF , &HFF 'Fuse setting. (ATtiny85 factory shipping condition)
'
' **********************************
' * PCF8574 I2C LCD Adapter test *
' * (For USI) 2021/ 5/ 3 *
' **********************************
'
$regfile = "ATtiny85.DAT" 'Set the AVR to use.
$crystal = 1000000 'Set the AVR clock.
'
$hwstack = 40 'Set the capacity of the hardware stack.
$swstack = 10 'Set the capacity of the software stack.
$framesize = 24 'Set the capacity of the frame area.
'
' * PCF8574 I2C LCD Adapter settings *
'
Const I2c_select = 1 '0:Software I2C , 1:USI
#if I2c_select = 0
'------[For software I2C]------
' $lib "i2cV2.LBX" 'Incorporate a modified version of the I2C library.
Config I2cdelay = 10 'SCL clock frequency. (*Up to 100KHz)
Config Scl = Portb.2 'Set the port pin to connect the SCL line of the I2C bus.
Config Sda = Portb.0 'Set the port pin to connect the SDA line of the I2C bus.
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#else
'------[For USI]------------------
Config Usi = Twimaster , Mode = Normal 'USI master settings. (I2C bus clock = 100KHz)
I2cinit 'Initialize the SCL and SDA lines of the I2C bus.
'-------------------------------
#endif
Dim Pcf8574_lcd As Byte : Pcf8574_lcd = &H4E 'PCF8574 slave address. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Dim Backlight As Byte : Backlight = 1 'LCD backlight control. (0: off, 1: on)
$lib "lcd_i2c_PCF8574.LIB" 'Incorporate the library of I2C LCD PCF8574 Adapter.
Config Lcd = 20x4 'Set the LCD to 20 characters and 4 lines.
Initlcd 'Initialize the LCD.
'
' ****************
' * Display test *
' ****************
'
Locate 1 , 1 'Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 2 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 'Write the custom character [Lightning] to the LCD.
Locate 1 , 15 'Display custom characters.
Lcd Chr(2) ; "1"
'
Locate 1 , 9 'Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
Wait 3
'
Backlight = 0 'Turn off the LCD backlight.
Locate 1 , 1 'Send a dummy command to control the backlight.
Wait 2
Backlight = 1 'Turn on the LCD backlight.
Locate 1 , 1 'Send a dummy command to control the backlight.
'
Locate 2 , 16 'Display the cursor.
Cursor On , Blink
End |
Last edited by O-Family on Tue Jul 12, 2022 7:36 am; edited 1 time in total |
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albertsm
Joined: 09 Apr 2004
Posts: 5921
Location: Holland
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| Posted: Tue May 04, 2021 9:21 am Post subject: |
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thank you for the update.
_________________
Mark |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Fri Jul 02, 2021 9:09 am Post subject: |
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We were able to confirm operation with XTINY (ATmega4809).
Please use Ver.002 of "lcd_i2c_PCF8574.LIB".
| Code: |
$programmer = 26 'MCS UPDI programmer
'
' **********************************
' * PCF8574 I2C LCD Adapter test *
' * (For XTINY) 2022. 7.12 *
' **********************************
'
$regfile = "mx4809.dat"
$crystal = 20000000
'
$hwstack = 64
$swstack = 10
$framesize = 24
Config Sysclock = 20mhz , Prescale = 1 ' System clock settings.
'
' * PCF8574 I2C LCD Adapter settings (For XTINY) *
'
Const I2c_select = 1 ' I2C interface selection. (0:Software I2C , 1:Hardware TWI)
'
#if I2c_select = 0 ' For software I2C.
Const Twi_adr = Twi0_ctrla : Const Twi_ch = 1 ' [Dummy in library]
$forcesofti2c ' Force use of software I2C/TWI library.
$lib "i2c.lbx" ' Overwrite the library for software I2C.
Config I2cdelay = 5 ' SCL clock frequency = approx 90KHz。(At AVR clock 20MHz) (* Maximum 100KHz)
Config Scl = Porta.7 ' Set the port pin to connect the SCL line of the I2C bus.
Config Sda = Porta.6 ' Set the port pin to connect the SDA line of the I2C bus.
I2cinit ' Initialize the I2C bus.
#else ' For hardware TWI.
Dim Twi_start As Byte ' Variables used in the TWI library.
Const Twi_adr = Twi0_ctrla ' TWI port. TWI_ADR = TWI0_CTRLA:(TWI0)
Const Twi_ch = 1 ' TWI channel. TWI_CH = 1:(TWI0), 2:(TWI1)
Config Twi0 = 100000 ' TWI clock frequency. (100KHz) (* Maximum 100KHz)
I2cinit ' Initialize the TWI bus.
#endif
'
Dim Pcf8574_lcd As Byte : Pcf8574_lcd = &H4E ' PCF8574 slave address. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Dim Backlight As Byte : Backlight = 1 ' LCD backlight control. (0: off, 1: on)
$lib "lcd_i2c_PCF8574.LIB" ' Incorporate the library of I2C LCD PCF8574 Adapter.
Config Lcd = 20x4 ' Set the LCD to 20 characters and 4 lines.
Initlcd ' Initialize the LCD.
'
' ****************
' * Display test *
' ****************
'
Do
Cls ' Clear all LCD displays.
Locate 1 , 1 ' Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 2 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 ' Write the custom character [Lightning] to the LCD.
Locate 1 , 15 ' Display custom characters.
Lcd Chr(2) ; "1"
'
Locate 1 , 9 ' Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
Wait 3
'
Backlight = 0 ' Turn off the LCD backlight.
Locate 1 , 1 ' Send a dummy command to control the backlight.
Wait 2
Backlight = 1 ' Turn on the LCD backlight.
Locate 1 , 1 ' Send a dummy command to control the backlight.
'
Locate 2 , 16 ' Display the cursor.
Cursor On , Blink
Wait 3
'
Locate 2 , 1
Lcd " < For XTiny > "
Wait 3
Loop
End
|
And add the code of XMega.
| Code: |
$programmer = 16 'USBprog Programmer/ AVR ISP mkII (Atmel)
'
' **********************************
' * PCF8574 I2C LCD Adapter test *
' * (For XMEGA) 2022. 7.12 *
' **********************************
'
$regfile = "xm128a1def.dat"
$crystal = 32000000
'
$hwstack = 64
$swstack = 40
$framesize = 40
Config Osc = Enabled , 32mhzosc = Enabled
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
'
' * PCF8574 I2C LCD Adapter settings (For XMEGA) *
'
Const I2c_select = 1 ' I2C interface selection. (0:Software I2C , 1:Hardware TWI)
'
#if I2c_select = 0 ' For software I2C.
Const Twi_adr = 0 : Const Twi_ch = 0 ' [Dummy in library]
$forcesofti2c ' Force use of software I2C/TWI library.
$lib "i2c.lbx" ' Overwrite the library for software I2C.
Config I2cdelay = 5 ' SCL clock frequency = approx 90KHz。(At AVR clock 32MHz) (* Maximum 100KHz)
Config Scl = Portc.7 ' Set the port pin to connect the SCL line of the I2C bus.
Config Sda = Portc.6 ' Set the port pin to connect the SDA line of the I2C bus.
I2cinit ' Initialize the I2C bus.
#else ' For hardware TWI.
Dim Twi_start As Byte ' Variables used in the TWI library.
Const Twi_adr = Twic_ctrl ' TWI port. TWI_ADR = TWIC_CTRL:(TWIC), TWID_CTRL:(TWID), TWIE_CTRL:(TWIE), TWIF_CTRL:(TWIF)
Const Twi_ch = 1 ' TWI channel. TWI_CH = 1:(TWIC), 2:(TWID), 4:(TWIE), 8:(TWIF)
Config Twic = 100000 ' Clock frequency of the TWI port [TWIC, TWID, TWIE, TWIF]. (* Maximum 100KHz)
I2cinit ' Initialize the TWI bus.
#endif
'
Dim Pcf8574_lcd As Byte : Pcf8574_lcd = &H4E ' PCF8574 slave address. (&H40,&H42,&H44,&H46,&H48,&H4A,&H4C,&H4E)
Dim Backlight As Byte : Backlight = 1 ' LCD backlight control. (0: off, 1: on)
$lib "lcd_i2c_PCF8574.LIB" ' Incorporate the library of I2C LCD PCF8574 Adapter.
Config Lcd = 20x4 ' Set the LCD to 20 characters and 4 lines.
Initlcd ' Initialize the LCD.
'
' ****************
' * Display test *
' ****************
'
Do
Cls ' Clear all LCD displays.
Locate 1 , 1 ' Display of title.
Lcd "PCF8574"
'
Locate 2 , 2
Lcd "I2C LCD Adapter"
'
Deflcdchar 2 , &H02 , &H04 , &H0C , &H1E , &H0F , &H06 , &H04 , &H08 ' Write the custom character [Lightning] to the LCD.
Locate 1 , 15 ' Display custom characters.
Lcd Chr(2) ; "1"
'
Locate 1 , 9 ' Display the slave address of PCF8574.
Lcd "[" ; Hex(pcf8574_lcd) ; "]"
Wait 3
'
Backlight = 0 ' Turn off the LCD backlight.
Locate 1 , 1 ' Send a dummy command to control the backlight.
Wait 2
Backlight = 1 ' Turn on the LCD backlight.
Locate 1 , 1 ' Send a dummy command to control the backlight.
'
Locate 2 , 16 ' Display the cursor.
Cursor On , Blink
Wait 3
'
Locate 2 , 1
Lcd " < For XMega > "
Wait 3
Loop
End
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Last edited by O-Family on Tue Jul 12, 2022 7:36 am; edited 2 times in total |
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autoguider
Joined: 24 Sep 2007
Posts: 82
Location: Aachen
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| Posted: Sat Nov 06, 2021 11:51 am Post subject: |
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Thx for the library.
I started compilation of the library Ver.002 dated 2021/05/13 with the LIB Manager tool and got following errors:
| Code: |
Error : 222 Line : 139 Illegal character [expected (, got ')' [LBYTE(TWI_ADR)]] , in File :
Error : 222 Line : 140 Illegal character [expected (, got ')' [HBYTE(TWI_ADR)]] , in File :
Error : 222 Line : 152 Illegal character [expected (, got ')' [LBYTE(TWI_ADR)]] , in File :
Error : 222 Line : 153 Illegal character [expected (, got ')' [HBYTE(TWI_ADR)]] , in File :
Error : 222 Line : 164 Illegal character [expected (, got ')' [LBYTE(TWI_ADR)]] , in File :
Error : 222 Line : 165 Illegal character [expected (, got ')' [HBYTE(TWI_ADR)]] , in File
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It is my first time to compile a library file. So it may be that I did something wrong.
Please be so kind and advise.
Christian |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Sun Nov 07, 2021 2:47 am Post subject: |
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| I don't know the hardware environment you have selected, so please attach a source that displays simple characters. |
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autoguider
Joined: 24 Sep 2007
Posts: 82
Location: Aachen
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| Posted: Sun Nov 07, 2021 11:15 am Post subject: |
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| I did not specify any hardware. I just did the compilation with the LIB-Tool. |
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albertsm
Joined: 09 Apr 2004
Posts: 5921
Location: Holland
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| Posted: Mon Nov 08, 2021 2:35 pm Post subject: |
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not all libs need to be compiled. in this case there is not need to compile it either. just include it with $LIB and the .LIB extension
if you actually want to use the lbx, the error is about : TWI_ADR it is unknown in the lib.
to solve that, put a * in front so it will be compiled when the app is compiled.
_________________
Mark |
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hawkfire
Joined: 15 Oct 2006
Posts: 14
Location: N.Wales U.K.
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| Posted: Fri Nov 12, 2021 11:14 pm Post subject: |
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I have been trying to get this working but unfortunately it seems to elude me.I am using Microchip's mcp23008 i2c port chip, instead of the pcf8574 with a few library modifications, although I have verified the port chip to be working with correct output, I still get blank on my screen. I would also like to point out that the 'backlight' arrangement circuit appears to have a full 5Volts across the input of the transistor base emitter junction, pulled up with a 4k7 resistor.??, how the bjt is suppose to survive this is beyond my comprehension.  |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Sat Nov 13, 2021 4:31 am Post subject: |
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MCP23008 does not work with this library because the commands to I2C are completely different from PCF8574.
Did you change your library for the MCP23008?
The backlight is turned off when the output of the port is set to [L] level. |
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hawkfire
Joined: 15 Oct 2006
Posts: 14
Location: N.Wales U.K.
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| Posted: Sat Nov 13, 2021 11:43 am Post subject: |
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| O-Family wrote: | MCP23008 does not work with this library because the commands to I2C are completely different from PCF8574.
Did you change your library for the MCP23008? |
Yes, I modified the pcf8574 library to mcp23008 and the port is working but nothing on the display.
| O-Family wrote: | | The backlight is turned off when the output of the port is set to [L] level. |
Yes, but when it is turned on, your circuit shows full 5 Volt output across the base emitter junction of the transistor? the mcp23008 can happily source 25mA |
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