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syndetic1
Joined: 02 Jan 2007
Posts: 76
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 Posted: Thu Dec 02, 2021 11:23 pm Post subject: XMEGA I2C |
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Hi guys,
I am stuck getting the I2C to work on a XMEGA128A1
I cant get it to work with either Hardware or Software I2C (Code below).
It's gets stuck on the I2C start. So whatever I am doing it's pretty fundamental. By stuck, I mean the program hangs.
It does not matter what I2C address I use. I do have a AT30TS74 I2C temperature sensor connected but I would have thought that the code should run even if there is nothing on the bus?
I put a CRO on the SCL line and with the hardware version of the code, get not clock pulses and with the software version, I get 1 clock pulse.
So Whatever I am doing is pretty basic.
SOFTWARE VERSION
| Code: |
'*******************************************************************************
' FILENAME: ATXMEGA128A1 ADC Test x.bas
'
' PROCESSOR: ATXMEGA128A1
' CLOCK: 16Mhz XTAL
' TITLE:
' BOARD: 0420-04 and 0420-01
' MODIFIED: 3-DEC-2021
' AUTHOR: Frank Thomson
' Based on example https://avrhelp.mcselec.com/index.html?using_the_i2c_protocol.htm
'*******************************************************************************
$regfile = "xm128A1Udef.dat" '"xm128A1Udef.dat" ' "C:\MCS\BASCAVR2082\DAT\xm128A1Udef.dat"
$framesize = 200 ' After global variables then after unused SRAM, grows bottom up, string conversion routines (PRINT, LCD, INPUT) require a buffer in SRAM
$swstack = 200 ' ISR routine parameters and grow top down
$hwstack = 200 ' Return address after routine call (SUB, FUNCTION, GOSUB) and grow top down
$crystal = 16000000
'Config Osc = Enabled , 32mhzosc = Enabled ' enable 2 MHz and 32 MHz internal oscillators
'Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
Config osc = enabled , EXTOSC = enabled , 32KHZOSC =DISABLED, pllosc = enabled , range = 12MHZ_16MHZ , startup = XTAL_16KCLK , pllsource = extclock , pllmul = 1
Config Sysclock = PLL , Prescalea = 1 , Prescalebc = 1_1
Disable Jtag
'--------{INITIALSE SOFT I2C}----------------------------------
$FORCESOFTI2C
Config I2cdelay = 10
$lib "i2c.lbx" ' Software I2C
'----{ INITIALIZE HARDWARE}------------------------------------
' PORTS A,B, C, D, E, F, H, J, K, Q Default to ALL INPUTS on Reset
' Port D which has a LED
'PORT D.0 - 0 0 LED SPARE 2
' D.1 - 0 0 LED SPARE 1
' D.2 - 0 0 LED FAIL
' D.3 - 0 0 LED STATUS
' D.4 - 0 0 LED TESTING
' D.5 - 0 0 LED DEVICE
' D.6 - 0 0 Reserved for USB N
' D.7 - 0 0 Reserved for USB N
' 76543210
Config PortD = &B00000011
PortD = &B00000000
' F
'PORT F.0 - 0 0 I2C SDA Temperature Sensor
' F.1 - 0 0 I2C SCL Temperature Sensor
' F.2 - 0 0 USART F0 RXD Goes to the GPS
' F.3 - 0 0 USART F0 TXD GPS
' F.4 - 0 0 Shaker
' F.5 - 0 0 Electromagnet
' F.6 - 0 0 USART F1 RXD
' F.7 - 0 0 USART F1 TXD Auxillary AVR
' 76543210
Config PortF = &B00000000
PortF = &B00000000
'---{I2C}--------------------------------
'Config TWI & TWI1 are for ATMEGA. TWIC, TWID, TWIE, TWIF for XMEGA
' Hardware I2C initialise
'Open "TWIF" For Binary As #4 ' or use TWID,TWIE oR TWIF
'Config TWIF = 100000 ' 100kHz
'I2cinit #4
'--{SOFTWARE I2C}-------------------------
config sda = portF.0
Config SCL = PortF.1
I2cinit
'---- INITIALISE COMMS ---------------------------------------------------------------------
Config Com5 = 9600 , mode = ASYNCHRONEOUS, Parity = None , Stopbits = 1 , Databits = 8
Open "COM5:" For Binary As # 6
Config Serialin6 = Buffered , Size = 10
'--{VARIABLES}-------------------------
Dim LEDcounter as word
Dim B as byte
B =&b10011110 ' Address of AT30TS74 temperature sensor
'-----MAIN PROGRAM START---------------------------------------------------------------------
portd.0 = 1 ' LED SPARE 2 ON
Print # 6 ,
print # 6, "AT X Mega 128A1U I2C Test Program"
print # 6, "Software I2C Version"
loopforever :
Print # 6, "I2C START"
I2Cstart
Print # 6, "Start Error : " ; Err ' show error
I2CWBYTE B
Print # 6, "Write Error : " ; Err ' show error
I2cstop
Print # 6, "Stop Error : " ; Err ' show error
' Heartbeat LED
LEDcounter = LEDcounter + 1
if LEDcounter >= 60000 then
toggle portd.1 'FAIL LED ON OFF
LEDcounter = 0
end if
goto loopforever
|
HARDWARE VERSION
| Code: |
'*******************************************************************************
' FILENAME: ATXMEGA128A1 ADC Test x.bas
'
' PROCESSOR: ATXMEGA128A1
' CLOCK: 16Mhz XTAL
' TITLE:
' BOARD: 0420-04 and 0420-01
' MODIFIED: 3-DEC-2021
' AUTHOR: Frank Thomson
' Based on example https://avrhelp.mcselec.com/index.html?using_the_i2c_protocol.htm
'*******************************************************************************
$regfile = "xm128A1Udef.dat" '"xm128A1Udef.dat" ' "C:\MCS\BASCAVR2082\DAT\xm128A1Udef.dat"
$framesize = 200 ' After global variables then after unused SRAM, grows bottom up, string conversion routines (PRINT, LCD, INPUT) require a buffer in SRAM
$swstack = 200 ' ISR routine parameters and grow top down
$hwstack = 200 ' Return address after routine call (SUB, FUNCTION, GOSUB) and grow top down
$crystal = 16000000
'Config Osc = Enabled , 32mhzosc = Enabled ' enable 2 MHz and 32 MHz internal oscillators
'Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
Config osc = enabled , EXTOSC = enabled , 32KHZOSC =DISABLED, pllosc = enabled , range = 12MHZ_16MHZ , startup = XTAL_16KCLK , pllsource = extclock , pllmul = 1
Config Sysclock = PLL , Prescalea = 1 , Prescalebc = 1_1
Disable Jtag
'--------{INITIALSE SOFT I2C}----------------------------------
'$FORCESOFTI2C
'Config I2cdelay = 10
'$lib "i2c.lbx" ' Software I2C
'----{ INITIALIZE HARDWARE}------------------------------------
' PORTS A,B, C, D, E, F, H, J, K, Q Default to ALL INPUTS on Reset
' Port D which has a LED
'PORT D.0 - 0 0 LED SPARE 2
' D.1 - 0 0 LED SPARE 1
' D.2 - 0 0 LED FAIL
' D.3 - 0 0 LED STATUS
' D.4 - 0 0 LED TESTING
' D.5 - 0 0 LED DEVICE
' D.6 - 0 0 Reserved for USB N
' D.7 - 0 0 Reserved for USB N
' 76543210
Config PortD = &B00000011
PortD = &B00000000
' F
'PORT F.0 - 0 0 I2C SDA Temperature Sensor
' F.1 - 0 0 I2C SCL Temperature Sensor
' F.2 - 0 0 USART F0 RXD Goes to the GPS
' F.3 - 0 0 USART F0 TXD GPS
' F.4 - 0 0 Shaker
' F.5 - 0 0 Electromagnet
' F.6 - 0 0 USART F1 RXD
' F.7 - 0 0 USART F1 TXD Auxillary AVR
' 76543210
Config PortF = &B00000000
PortF = &B00000000
'---{I2C}--------------------------------
'Config TWI & TWI1 are for ATMEGA. TWIC, TWID, TWIE, TWIF for XMEGA
' Hardware I2C initialise
Open "TWIF" For Binary As # 4 ' or use TWID,TWIE oR TWIF
Config TWIF = 100000 ' 100kHz
I2cinit # 4
'--{SOFTWARE I2C}-------------------------
'config sda = portF.0
'Config SCL = PortF.1
'I2cinit
'---- INITIALISE COMMS ---------------------------------------------------------------------
Config Com5 = 9600 , mode = ASYNCHRONEOUS, Parity = None , Stopbits = 1 , Databits = 8
Open "COM5:" For Binary As # 6
Config Serialin6 = Buffered , Size = 10
'--{VARIABLES}-------------------------
Dim LEDcounter as word
Dim B as byte
B =&b10011110 ' Address of AT30TS74 temperature sensor
Dim TWI_START as Byte ' Required by Bascom TWI Library code
'-----MAIN PROGRAM START---------------------------------------------------------------------
portd.0 = 1 ' LED SPARE 2 ON
Print # 6 ,
print # 6, "AT X Mega 128A1U I2C Test Program"
print # 6, "HARDWARE I2C Version"
loopforever :
Print # 6, "I2C START"
I2Cstart # 4
Print # 6, "Start Error : " ; Err ' show error <--- Never gets to here
I2CWBYTE B , # 4
Print # 6, "Write Error : " ; Err ' show error
I2cstop # 4
Print # 6, "Stop Error : " ; Err ' show error
' Heartbeat LED
LEDcounter = LEDcounter + 1
if LEDcounter >= 60000 then
toggle portd.1 'FAIL LED ON OFF
LEDcounter = 0
end if
goto loopforever
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(BASCOM-AVR version : 2.0.8.4 ) |
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MWS
Joined: 22 Aug 2009
Posts: 2262
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| Posted: Fri Dec 03, 2021 2:02 am Post subject: |
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Your code addressing the I2C device seems incomplete.
Usually it goes:
Start
Send R or W address
Restart
Send command or register address to access
Do reads or further writes
Stop
The read or write address requires to include the rightmost R/W bit, read address of the device is &h91, write is &h90, provided A0..2 = 0. |
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Tiny
Joined: 10 Nov 2010
Posts: 101
Location: The Netherlands
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| Posted: Fri Dec 03, 2021 8:09 am Post subject: |
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Hello,
the first thing to test is that the scl and sda pin are a logic "1" in idle state before you are going to communicate over the i2c bus.
then do a i2c bus scan see the example "xmega-scanner.bas" that comes with Bascom to ensure that the slave device is responding
Regards,
Tiny |
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syndetic1
Joined: 02 Jan 2007
Posts: 76
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| Posted: Sun Dec 05, 2021 6:34 am Post subject: Still Stuck |
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I copied xmega-scaner.bas and made minimum modifications to suit may hardware.
Basically I am using UART5 for my serial comms.
and I am using the U version of the chip
The program sends the I2cstart and comes back
but never comes back from I2cwbyte
It just hangs
Also I tried simulating the original xmega-scanner.bas and it get's stuck at exactly the same place.
| Code: |
'------------------------------------------------------------------
' (c) 1995-2020 MCS
' xmega-scanner.bas
'purpose : scan all i2c addresses to find slave chips
'Micro: Xmega128A1
'
' Changed 5-DEC-2021 Frank Thomson
'
'------------------------------------------------------------------
'---{CHANGES FROM THE ORIGINAL}------------------------------------
'1. .def file changed from xM128a1def.dat to xm128A1Udef.dat
'2. Com5 used for serial Note open as #6
'------------------------------------------------------------------
$regfile = "xm128A1Udef.dat" ' the used chip {We are using a U}
$crystal = 32000000 ' frequency used
$hwstack = 40
$swstack = 40
$framesize = 40
'first enable the osc of your choice
Config Osc = Enabled , 32mhzosc = Enabled
'configure the systemclock
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
'Config Com1 = 19200 , Mode = Asynchroneous , Parity = None , Stopbits = 1 , Databits = 8
'Config Serialin = Buffered , Size = 50
'---- INITIALISE COMMS ---------------------------------------------------------------------
Config Com5 = 9600 , mode = ASYNCHRONEOUS, Parity = None , Stopbits = 1 , Databits = 8
Open "COM5:" For Binary As #6
Config Serialin6 = Buffered , Size = 10
'------------------------------------------------------------------------------------------
Config Twic = 100000 'CONFIG TWI will ENABLE the TWI master interface - We are using F
'Enable Interrupts
'Open "COM1:" For Binary As #1
I2cinit
Dim Twi_start As Byte , B As Byte
Print #6, "Scan start"
For B = 0 To 254 Step 2 'for all odd addresses
I2cstart : Print #6, "I2C Started" 'send start
I2cwbyte B : Print #6, "I2cwbyte B -> "; B 'send address <---- HANGS HERE-------
If Err = 0 Then 'we got an ack
Print #6, "Slave at : " ; B ; " hex : " ; Hex(b) ; " bin : " ; Bin(b)
End If
I2cstop 'free bus
Next
Print #6, "End Scan"
End
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MWS
Joined: 22 Aug 2009
Posts: 2262
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| Posted: Sun Dec 05, 2021 1:13 pm Post subject: |
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Power supply for AT30TS74 is 3.3 or 5.0V?
Pull-ups to SCL/SDA are installed?
Pulling to 3.3 or 5.0V? |
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syndetic1
Joined: 02 Jan 2007
Posts: 76
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| Posted: Sun Dec 05, 2021 10:43 pm Post subject: |
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| MWS wrote: | Power supply for AT30TS74 is 3.3 or 5.0V?
Pull-ups to SCL/SDA are installed?
Pulling to 3.3 or 5.0V? |
Everything is 3V3
Pullups installed.
I am also confused that xmega-scanner.bas when run in the simulator gets stuck at exactly the same point.
If there are zero devices on the I2C bus, I would have thought xmega-scanner.bas should still run and yet not find any devices. |
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MWS
Joined: 22 Aug 2009
Posts: 2262
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| Posted: Sun Dec 05, 2021 11:18 pm Post subject: |
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| syndetic1 wrote: | | I am also confused that xmega-scanner.bas when run in the simulator gets stuck at exactly the same point. |
I think simulation-detail goes not that far to simulate the hardware I2C unit, means the code is looping for a bit to set or clear and gets stuck. Which may happen on real hardware too, but out of different reasons.
| Quote: | | If there are zero devices on the I2C bus, I would have thought xmega-scanner.bas should still run and yet not find any devices. |
As long the code is executed on real hardware, I'd expect that too.
Hardware is double checked? Try out the scanner example with as little modifications as possible.
Try another TWI-unit, TWIE/F if possible. |
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syndetic1
Joined: 02 Jan 2007
Posts: 76
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| Posted: Mon Dec 06, 2021 12:04 am Post subject: |
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I have attached the schematic that applies to the original post. This has one I2C temperature sensor on the Port F I2C. The program hangs. It hangs irrespective of whether I configure for hardware or software I2C.
On my PCB, The Port C I2C is not connected to any I2C hardware but it is not damaged by configuring it for I2C. The original xmega-scanner.bas is written for Port C and it hangs too. |
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MWS
Joined: 22 Aug 2009
Posts: 2262
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| Posted: Mon Dec 06, 2021 12:49 am Post subject: |
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R101/102 are harmful, remove them, R103/104 are factor 10 too high, 4k7 is more appropriate.
I2CInit enables internal pullips on the pins, these are in the range of 15k to 20k.
All together this creates a voltage divider, where no one is desired and it slurs the signals edges, confuses the controller. |
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MWS
Joined: 22 Aug 2009
Posts: 2262
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| Posted: Tue Dec 07, 2021 12:06 pm Post subject: Re: Still Stuck |
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| syndetic1 wrote: | | Code: | Config Twic = 100000 'CONFIG TWI will ENABLE the TWI master interface - We are using F |
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In your schematic you use port F, you need to write:
| Code: | Config Twif = 100000 |
EDIT:
Try this, simulated as far as possible and checked that every I2C-command works on the right bus.
If the "inactive bus timeout" disturbs the scanner's function, remove it, this option is for bus-recovery.
| Code: | $regfile = "xm128A1Udef.dat"
$crystal = 32000000
$hwstack = 40
$swstack = 40
$framesize = 40
'$sim
Config Osc = Enabled , 32mhzosc = Enabled
Config Sysclock = 32mhz , Prescalea = 1 , Prescalebc = 1_1
'---- INITIALISE COMMS ---------------------------------------------------------------------
#IF _SIM = 0
Config Com5 = 9600 , mode = ASYNCHRONEOUS, Parity = None , Stopbits = 1 , Databits = 8
Open "COM5:" For Binary As #6
#ENDIF
'------------------------------------------------------------------------------------------
Open "twif" For Binary As #4
Config Twif = 100000
Set TWIF_MASTER_CTRLB.2 ' sets Inactive Bus timeout to 50µs
I2cinit #4
Dim Twi_start As Byte , B As Byte
#IF _SIM = 0
Print #6, "Scan start"
#ENDIF
For B = 0 To 254 Step 2
I2cstart #4
#IF _SIM = 0
Print #6, "I2C Started"
#ENDIF
I2cwbyte B, #4
#IF _SIM = 0
Print #6, "I2cwbyte B -> "; B
#ENDIF
#IF _SIM = 0
If Err = 0 Then 'we got an ack
Print #6, "Slave at : " ; B ; " hex : " ; Hex(b) ; " bin : " ; Bin(b)
End If
#ENDIF
I2cstop #4 'free bus
Next
#IF _SIM = 0
Print #6, "End Scan"
#ENDIF
End |
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albertsm
Joined: 09 Apr 2004
Posts: 5917
Location: Holland
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| Posted: Tue Dec 07, 2021 2:46 pm Post subject: |
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when using $FORCESOFTI2C
you should not include the lib for the normal AVR : $lib "i2c.lbx" ' Software I2C
for the rest i agree with MWS comment about the resistors. and also config twic/twif
it seems the scl is kept low (clock stretching).
so you best check with a scope what is keeping this line low.
i would get rid of all the R's and the i2c chip as well. maybe your board is bad?
also see if you can manipulate the pins with normal code.
_________________
Mark |
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syndetic1
Joined: 02 Jan 2007
Posts: 76
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| Posted: Tue Dec 07, 2021 9:10 pm Post subject: |
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Thanks guys. The code posted by MWS on Tue Dec 07, 2021 12:06 pm was very helpful. It ran on my hardware.
Thanks again all. |
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