I2COut does it really need 'Control?

[Ecoli-557]

Thanks to All, Pepe, I will add the 1us delay for good measure.
I now need to read back from a few registers to ensure they got written what I wanted!

[Pepe]

Delayus 1 can be replaced by some nop

[Ecoli-557]

I am attempting to read back what I am writing to these registers as a way to ensure I am correct.
I have used Pepe's fragment to be this:

Code Select Expand

' Procedure to read from the WM8940
Proc ReadWM8940 (CODECReg As Byte) ,SPI_in as Word
    lOW CODEC_CS
    shOut SDA_Pin, SCL_Pin, 5, [CODECReg\8]
    High CODEC_CS
    delayus 1
    Low CODEC_CS
    SHIn SDA_Pin, SCL_Pin, 5, [SPI_in\16]
    high CODEC_CS
EndProc

and call it by this:

Code Select Expand

     ReadWM8940(CODEC_Pwr1)
     HSerOut ["PWR1 SPI_in=", hex4 SPI_in, " \n\r"]
     ReadWM8940(CODEC_DAC)
     HSerOut ["DAC SPI_in=", hex4 SPI_in, " \n\r"]
     readWM8940(CODEC_Clk)
     HSerOut ["CLK SPI_in=", hex4 SPI_in, " \n\r"]
     readWM8940(CODEC_AddlCntl)
     HSerOut ["AddlCntl SPI_in=", hex4 SPI_in, " \n\r"]
     readWM8940(CODEC_Pwr3)
     HSerOut ["Pwr3 SPI_in=", hex4 SPI_in, " \n\r"]

Using Mode 4, 5 and 7, I receive all I receive in SPI_In is 0xFFFF.
I am missing something quite simple.....

[Ecoli-557]

I just realized that I am looking at this all wrong.
According to the timing diagram:

I STLL need to send the register address with the high-order 8-bit set.
Working on it .

[Pepe]

The manual says that only registers 0, 1, and 32 can be read.

Code Select Expand

' Procedure to read from WM8940 using 3-wire protocol
Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    CODECReg = (CODECReg & $7f) << 1
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg] 
    SHIn SDA_Pin, SCL_Pin, 5,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc


[Pepe]

Code Select Expand

' Procedure to write WM8940 using 3-wire protocol
Proc WriteWM8940(CODECReg As Byte, Wdata As Word)
    CODECReg = ((CODECReg & $7F )<<1)| 1
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg,Wdata]
    High CODEC_CS
EndProc


[Ecoli-557]

The manual says that only registers 0, 1, and 32 can be read.

Yes, I read that as well and thought it was curious why you cannot read back from a register you can write to.....
[quote

Code Select Expand

' Procedure to read from WM8940 using 3-wire protocol
Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    CODECReg = (CODECReg & $7f) << 1
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg] 
    SHIn SDA_Pin, SCL_Pin, 5,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc
[/quote]
I will use this Thanks Pepe, and 1st see what the 3 registers offer and then try others.
Curious little CODEC indeed.

[Ecoli-557]

Pepe- I must be missing from your example.  This is my code:

Code Select Expand

' Procedure to read from the WM8940 using 3-wire protocol
Proc ReadWM8940 (CODECReg As Byte) ,Word
    CODECReg = (CODECReg & 0x7f) << 1
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg]
    SHIn SDA_Pin, SCL_Pin, 5, [SPI_in\16]
    high CODEC_CS
EndProc
And how I call it:

Code Select Expand

     ReadWM8940(CODEC_RST)                   'Should return Chip ID
     HSerOut ["RST SPI_in=", hex4 SPI_in, " \n\r"]
     ReadWM8940(CODEC_Pwr1)                  'Should return device revision
     HSerOut ["PWR1 SPI_in=", hex4 SPI_in, " \n\r"]
     ReadWM8940(CODEC_ALC1)                  'Should return ALC gain
On these and 3 others picked, all return 0xFFFF

[tumbleweed]

In order to read a register you need to set the msb of the address byte, not clear it and shift it left

[Pepe]

Test this

Code Select Expand


Dim wdato as word

wdato= ReadWM8940(CODEC_RST)

HSerOut ["chip id =", dec wdato, " \n\r"]
Do
Loop

' Procedure to read from WM8940 using 3-wire protocol
Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    CODECReg = CODECReg | $80
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg]
    SHIn SDA_Pin, SCL_Pin, 7,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc

' Procedure to write WM8940 using 3-wire protocol
Proc WriteWM8940(CODECReg As Byte, Wdata As Word)
    CODECReg = CODECReg & $7F
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg,Wdata\16]
    High CODEC_CS
EndProc


[Ecoli-557]

Thanks Tumbleweed and Pepe.
I will test this but it will need to wait about 4 days.
I have to be in Houston until Friday.
Regards to all,
Steve

[Ecoli-557]

I am back now, got back early.
Pepe:
This is the read proc:

Code Select Expand

' Procedure to read from WM8940 using 3-wire protocol
Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    CODECReg = CODECReg | $80
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg]
    SHIn SDA_Pin, SCL_Pin, 7,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc

And this is how I used it based on your input:

Code Select Expand


Dim wdato as word
wdato= ReadWM8940(CODEC_RST)
HSerOut ["chip id =", dec wdato, " \n\r"]

and this is what came back from Hserout:

Code Select Expand

[13:44:20 --- Rx] chip id =65535

I may go back and change the way I talking to the chip - perhaps start with a traditional I2C with the fixed address?

[Pepe]

Is CODECReg high when the codec is turned on? You can try removing | $80

[Ecoli-557]

Is CODECReg high when the codec is turned on? You can try removing | $80

The CODEC chip sel is HIGH.  I did try '|0x80' in another attempt as you have to set the high-order 8-bit to READ from the register - it made no difference.
This is why I may try going back to the regular I2C communication structure and use the set address....... although the manual (not entirely clear) says you can use the Chip Select if you set the MODE pin HIGH - which I have.

[Pepe]

Test Declare Shift_DelayUs = 1

[Ecoli-557]

Test Declare Shift_DelayUs = 1

My Decalars:

Code Select Expand

Device = 18F67K40
Declare Xtal = 64
On_Hardware_Interrupt GoTo My_IRQ
Declare Optimiser_Level = 0 'DISABLES the Optimiser
Declare I2C_Slow_Bus On     '64MHz may be too fast for the WM8940
Declare Shift_DelayUs = 1

AND, I noticed the register queried was incorrect, instead of CODEC_RST which is register '0x00' it should be register CODEC_Pwr1 which is register '0x01' which return the Device Revision.

Code Select Expand

Dim wdato as word
wdato= ReadWM8940(CODEC_PWR1)
HSerOut ["chip id =", dec wdato, " \n\r"]

Result:

Code Select Expand

[14:23:07 --- Rx] chip id =65535

Still not returning a correct reading I suspect.

[Pepe]

Test this

Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg]
    SHIn SDA_Pin, SCL_Pin, 7,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc

[Pepe]

 R0 Software Reset.   15:0 CHIP_ID
 R1 Power Management 1 2:0 DEVICE_REVISION

[Ecoli-557]

Test this

Proc ReadWM8940(CODECReg As Byte), Word
    Dim ReadValue As Word
    Low CODEC_CS
    SHOut SDA_Pin, SCL_Pin, 5,[CODECReg]
    SHIn SDA_Pin, SCL_Pin, 7,[ReadValue\16]
    High CODEC_CS
    Result = ReadValue
EndProc

Where do you equate the result from the Procedure to the query?

Code Select Expand

Dim wdato as word
wdato= ReadWM8940(CODEC_PWR1)
HSerOut ["chip id =", dec wdato, " \n\r"]


[Ecoli-557]

R0 Software Reset.   15:0 CHIP_ID
 R1 Power Management 1 2:0 DEVICE_REVISION

Yes, I overlooked that