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DirkBischof
Joined: 25 May 2013
Posts: 2
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 Posted: Mon Jun 14, 2021 11:38 pm Post subject: Read Data from MCP23017 I2C |
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Hello,
i use a few MCP23017 for output and inputs.
The outputs working well...but i can't read the inputs.
i start with the AN245 for the MCP23016
[code]
'**********************************************************************
' Application Note: Using the MCP23017 I/O expander
'-----------------------------------------------------
'
' Program-ID.: AN245 MCP23017.bas.
' Date...... : 22 / 05 / 2005
' Description: Example program for I2C MCP23017 I/O expander
' write and read routines.
'
' Author : Roland van leusden (sayang@zonnet.nl).
'
' Setup for the AT90S2313 using portd.6 for SDA and Portd.5 for SCL.
' (Futurlec ET-JRAVR board)
' See AN245 page 9 from Microchip for MCP23017 shematic.
'
' This program provides an example for writing to and reading from
' an I2C MCP23017 device wired for device 0 (AO,A1 and A2 all pulled
' to Gnd).
'
'
'**********************************************************************
$regfile = "m328pdef.dat" ' Change for your AVR
$crystal = 16000000 ' 4 MHz Crystal.
'$regfile = "m8def.dat" ' Change for your AVR.
'$crystal = 20000000 ' 4 MHz Crystal.
$baud = 9600 ' Output at 19200 baud.
'**********************************************************************
'** Set up Data Direction Registers and ports - Do this before defining I2C pins!
'**********************************************************************
' Port B
Portb = &B0000_0000 ' Set All Port Pins Low
Ddrb = &B1111_1111 ' Set Unused Pins As Outputs.
' Port D
Portd = &B0000_0000 ' All low - with push-pull output
Ddrd = &B1111_1111 ' with internal pullups.
'**********************************************************************
'** Define and initialize I2C pins **
'**********************************************************************
Config Sda = PortC.4 ' I2C Data.
Config Scl = Portc.5 ' I2C Clock.
'**********************************************************************
'
'** Declare subroutines **
'**********************************************************************
'
' This subroutine writes data to the I2C MCP23017.
'
Declare Sub I2c_mcp23017_write(byval Cmd As Byte , Byval Lsb As Byte , Byval Msb As Byte)
'
' This subroutine reads data from the I2C MCP23017.
'
Declare Sub I2c_mcp23017_read
Declare Sub I2c_scan
'**********************************************************************
'** Define working variables and constants **
'**********************************************************************
'
' Change the 3 "AD" bits to reflect the I2C address of the device
' (corresponding to A0,A1 and A2)..
'
Dim Mcp23017_adress_w As Byte
Mcp23017_adress_w = &H40 'Write Adress: 0 1 0 0 A2 A1 A0 0
Dim Mcp23017_adress_r As Byte
Mcp23017_adress_r = &H41 'Read Adress: 0 1 0 0 A2 A1 A0 1
Dim Counter_1 As Byte
Dim Lsb As Byte
Dim Msb As Byte
Dim B As Byte
'This is for the Microchip MCP23017 initialization, some examples below
'Call I2c_mcp23017_write(&H04 , &Hff , &Hff) 'Invert All Input Polarities
'Call I2c_mcp23017_write(&H0a , &H01 , &H01) 'Initialize Iares , For Fast Input Scan Mode
'Call I2c_mcp23017_write(&H06 , &H00 , &HFF) 'Initiallize It So The Lsbs Outputs Are & Msbs Are Inputs
'Call I2c_mcp23017_write(&H06 , &Hff , &Hff) 'Initiallize It So That Both Lsbs & Msbs Are Inputs
'Call I2c_mcp23017_write(&H02 , &HFF , &HFF) 'Initiallize The Ouput Latch
'Call I2c_mcp23017_write(&H06 , &H00 , &H00) 'Initiallize It So That Both Lsbs & Msbs Are Outputs
'**********************************************************************
'** Actual work starts here. **
'**********************************************************************
Main:
Wait 1
Print "MCP23017 "
Wait 1
Print "scanne I2C-Bus"
Print ".."
Call I2c_scan
Waitms 250 ' wait 250 ms for the MCP23017 powerup timer
Call I2c_mcp23017_write(&H02 , &HFF , &HFF) 'Initiallize The Ouput Latch
Call I2c_mcp23017_write(&H06 , &H00 , &H00) 'Initiallize It So That Both Lsbs & Msbs Are Outputs
Lsb = &HFE '0 => Led is "on" FE => 11111110
Msb = &HFE '0 => Led is "on" FE => 11111110
Counter_1 = 0
Do 'Chaser effect
Call I2c_mcp23017_write(&H02 , Lsb , Msb) 'Write Lsb & Msb to MCP23017
Rotate Lsb , Left , 1 'Rotate the bits
Rotate Msb , Left , 1
Waitms 100 'Wait 100ms
Counter_1 = Counter_1 + 1 ' Increase the counter
Print "Counter_1: " ; Counter_1
Loop Until Counter_1 = 255 ' As long as the counter is not 255 keep writing & rotating
Lsb = &HFF '0 => Led is "on" FF => 11111111
Msb = &HFF
Call I2c_mcp23017_write(&H02 , Lsb , Msb) 'All leds off
Call I2c_mcp23017_write(&H06 , &H00 , &HFF) 'Initiallize It So The Lsbs Outputs Are & Msbs Are Inputs
Do 'Read Msb and display on Lsb
Call I2c_mcp23017_read ' Read Msb
Print "Read Msb: " ; Msb ' Send value of Msb to serial port
Lsb = Msb ' Copy Msb to Lsb
Call I2c_mcp23017_write(&H02 , Lsb , Msb) ' Write Lsb to MCP23017
Waitms 100 'Wait 100ms
Loop
End 'end program
'**********************************************************************
'** Define Subroutines **
'**********************************************************************
Sub I2c_mcp23017_write(byval Cmd As Byte , Byval Lsb As Byte , Byval Data2 As Byte)
' Writes data to the I2C MCP23017.
I2cstart 'Generate A Start Condition
I2cwbyte Mcp23017_adress_w 'Transmit The "ADDRESS and WRITE" Byte
I2cwbyte Cmd 'Transmit The Command Byte
I2cwbyte Lsb 'Transmit First Data Byte
I2cwbyte Msb 'Transmit Second Data Byte
If Err > 0 Then
Print " MCP23017 Error : " ; Err ' show error
End If
I2cstop 'Generate a STOP condition
Waitus 50 'Some delay may be necessary for back to back transmitions
End Sub
Sub I2c_mcp23017_read
' Read data from the I2C MCP23017
I2cstart 'Generate START condition
I2cwbyte Mcp23017_adress_w 'Transmit The "ADDRESS and WRITE" Byte
I2cwbyte &H00 'Transmit The Command Byte
I2cstop 'Generate a STOP condition
I2cstart 'Generate a START condition
I2cwbyte Mcp23017_adress_r 'Transmit ADDRESS with READ command
I2crbyte Lsb , Ack 'Receive first DATA byte (LSB) and acknowledge
I2crbyte Msb , Nack 'Receive second DATA byte (MSB) and don't acknowledge
If Err > 0 Then
Print " MCP23017 Error : " ; Err ' show error
End If
I2cstop 'Generate a STOP condition
End Sub
Sub I2c_scan ' check all devices on the I2c-bus
Print "Scan start I2C Bus"
For B = 0 To 254 Step 2 'for all odd addresses
I2cstart 'send start
I2cwbyte B 'send address
If Err = 0 Then 'we got an ack
Print "Slave at found " ; Hex(b)
End If
I2cstop 'free bus
Next
Print "End Scan I2C Bus"
End Sub
Do someone have a tip for me ?
Thanks a lot |
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O-Family
Joined: 23 May 2010
Posts: 320
Location: Japan
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| Posted: Tue Jun 15, 2021 2:41 am Post subject: |
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The register addresses of MCP23016 and MCP23017 are different.
| Code: | $regfile = "m328pdef.dat" ' Change for your AVR
$crystal = 16000000
$hwstack = 64
$swstack = 10
$framesize = 24
$baud = 9600
Dim I2cbuff(10) As Byte 'I2C send / receive data buffer.
Dim Mcp23017_gpa As Byte 'MCP23017 GPIOA
Dim Mcp23017_gpb As Byte 'MCP23017 GPIOB
'**********************************************************************
'** Define and initialize I2C pins **
'**********************************************************************
Config Sda = Portc.4 ' I2C Data.
Config Scl = Portc.5 ' I2C Clock.
I2cinit 'Initialize the I2C bus.
Dim Mcp23017_adress As Byte
Mcp23017_adress = &H40 'MCP23017 Adress: 0 1 0 0 A2 A1 A0 0
Wait 1
Print "MCP23017 "
Wait 1
'
' * Initial setting of MCP23017 *
'
I2cbuff(1) = &H00 'Register address = [IODIRA]
I2cbuff(2) = &B0000_0000 'Set the GPA port to output.
I2cbuff(3) = &B1111_1111 'Set the GPB port to input.
I2csend Mcp23017_adress , I2cbuff(1) , 3 'Send 3 bytes of data to MCP23017.
I2cbuff(1) = &H0D 'Register address = [GPPUB]
I2cbuff(2) = &B1111_1111 'Enable GPB port pull-up.
I2csend Mcp23017_adress , I2cbuff(1) , 2 'Send 2 bytes of data to MCP23017.
Main:
Do 'Read Msb and display on Lsb
I2cbuff(1) = &H13 'Register address = [GPIOB]
I2creceive Mcp23017_adress , I2cbuff(1) , 1 , 1 'Sends 1 byte to MCP23017 and receives 1 byte.
Mcp23017_gpb = I2cbuff(1)
Print "Read GPB: " ; Bin(mcp23017_gpb)
I2cbuff(1) = &H12 'Register address = [GPIOA]
I2cbuff(2) = Mcp23017_gpb 'Data to be output to [GPIOA].
I2csend Mcp23017_adress , I2cbuff(1) , 2 'Send 2 bytes of data to MCP23017.
Waitms 100 'Wait 100ms
Loop
End 'end program |
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DirkBischof
Joined: 25 May 2013
Posts: 2
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| Posted: Tue Jun 15, 2021 5:19 pm Post subject: reading from MCP23017 |
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hello O-Family
MANY THANKS it works fine !
greetings from Hamburg Germany to Japan !  |
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