AOut driving

[sparx]

Have been attempting to get a DOut x 2 working on J19, have read the documentation and tried the examples, but its not behaving how I would expect it to.

What I need it to do is to get a value from an encoder position, which will be 4 bits and put this out to the 595’s. Ultimately it will be two encoders, 4 bits each, making up a byte.

At the moment, the value is shifted left 9 places and is set to count to 255, however after it gets to 64, incorrect values are displayed on the 595 output.

Its being initialised like this:

// initialize AOUT module

  AOUT_Init(0);


  // configure interface

  // see AOUT module documentation for available interfaces and options

  aout_config_t config;

  config = AOUT_ConfigGet();

  config.if_type = AOUT_IF_74HC595;

  config.if_option = 0xffffffff;

  config.num_channels = 8; // INTDAC: only 2 channels supported, 8 channels pre-configured for your own comfort

  config.chn_inverted = 0;

  AOUT_ConfigSet(config);

  AOUT_IF_Init(0);

And sent to the 595’s on J19 like this:

AOUT_PinSet(1,value<<9);

AOUT_Update();

Can anyone see what is going wrong?

Thanks all

Regards

S

[Shuriken]

Have been attempting to get a DOut x 2 working on J19, have read the documentation and tried the examples, but its not behaving how I would expect it to.

What I need it to do is to get a value from an encoder position, which will be 4 bits and put this out to the 595’s. Ultimately it will be two encoders, 4 bits each, making up a byte.

At the moment, the value is shifted left 9 places and is set to count to 255, however after it gets to 64, incorrect values are displayed on the 595 output.

Its being initialised like this:

// initialize AOUT module

  AOUT_Init(0);


  // configure interface

  // see AOUT module documentation for available interfaces and options

  aout_config_t config;

  config = AOUT_ConfigGet();

  config.if_type = AOUT_IF_74HC595;

  config.if_option = 0xffffffff;

  config.num_channels = 8; // INTDAC: only 2 channels supported, 8 channels pre-configured for your own comfort

  config.chn_inverted = 0;

  AOUT_ConfigSet(config);

  AOUT_IF_Init(0);

And sent to the 595’s on J19 like this:

AOUT_PinSet(1,value<<9);

AOUT_Update();

Can anyone see what is going wrong?

Thanks all

Regards

S

In the first sentence you say DOUT. But the code is for AOUT. So what is it?

[TK.]

The AOUT driver behaves like expected, because it only supports 12/4 and 8/8 bit mode as described here:

//!  <LI>2 (AOUT_IF_74HC595):<BR>

//!      CV: up to 32 cascaded 74HC595 (each MBHP_AOUT_LC module provides 2 74HC595)<BR>

//!      Resolution is selectable with interface_option, each 74HC595 has an own bit

//!      which define:

//!      <UL>

//!        <LI>0: 12/4 bit configuration

//!        <LI>1: 8/8 bit configuration

//!      </UL>

//!      Examples:

//!      <UL>

//!        <LI>0x00000000: all AOUT_LC modules used for 12/4 bit configuration

//!        <LI>0xffffffff: all AOUT_LC modules used for 8/8 bit configuration

//!        <LI>0x00000003: first AOUT_LC used for 8/8 bit configuration, all others for 12/4

//!        <LI>0x0000000c: second AOUT_LC used for 8/8 bit configuration, all others for 12/4

//!      </UL>

//!      Digital: none</LI>

[/code]


What are you planning to do exactly?


Wouldn't it be easier to output the values with DOUT modules connected to J8/J9?


Best Regards, Thorsten.

[sparx]

Thanks for the replies.

What I was trying to do was to use J19 for DOuts.

J8/J9 are practically full in the configuration I'm using, so was trying to find another way to get DOUTs.

Regards

S

[TK.]

You can use J19 for DOUTs of course - just access it directly with MIOS32_SPI functions like I did in the aout.c driver:

http://svnmios.midibox.org/filedetails.php?repname=svn.mios32&path=%2Ftrunk%2Fmodules%2Faout%2Faout.c

Initialisation:

#ifdef MIOS32_BOARD_MBHP_CORE_STM32

    // MBHP_CORE_STM32: pins in open drain mode (to pull-up the outputs to 5V)

    status |= MIOS32_SPI_IO_Init(AOUT_SPI, MIOS32_SPI_PIN_DRIVER_STRONG_OD);

#else

   // MBHP_CORE_LPC17 (and others): pins in push-poll mode (3.3V output voltage)

    status |= MIOS32_SPI_IO_Init(AOUT_SPI, MIOS32_SPI_PIN_DRIVER_STRONG);

#endif


    // init SPI port for fast frequency access

    status |= MIOS32_SPI_TransferModeInit(AOUT_SPI, MIOS32_SPI_MODE_CLK0_PHASE1, MIOS32_SPI_PRESCALER_4);

[/code]




Transfer of a single byte:

[code]

    u8 my_byte 0x42;

    MIOS32_SPI_TransferByte(AOUT_SPI, my_byte);


    // toggle RCLK pin

    MIOS32_SPI_RC_PinSet(AOUT_SPI, AOUT_SPI_RC_PIN, 1); // spi, rc_pin, pin_value

    MIOS32_SPI_RC_PinSet(AOUT_SPI, AOUT_SPI_RC_PIN, 0); // spi, rc_pin, pin_value

For multiple bytes just call MIOS32_SPI_TransferByte multiple times and capture the value by toggling the RCLK pin AOUT_SPI is set to:

// Which SPI peripheral should be used

// allowed values: 0 (J16), 1 (J8/9) and 2 (J19)

#ifndef AOUT_SPI

#define AOUT_SPI 2

#endif

[/code]


please use a different name


Best Regards, Thorsten.