lh7a400_lcd_evb_eeprom_driver.c

sharp触摸屏测试代码

/**********************************************************************
 *	$Workfile:   lh7a400_lcd_evb_eeprom_driver.c  $
 *	$Revision:   1.2  $
 *	$Author:   KovitzP  $
 *	$Date:   Nov 21 2001 11:38:28  $
 *
 *	Project: LH7A400
 *
 *	Description:
 *  This file contains a driver for the EEPROM device on the LCD
 *  board on LH7A400 evaluation board system.
 *  The EEPROM is a Microchip 93LC46B 64 x 16 EEPROM.
 *  Functions provided are:
 *   lcd_eeprom_driver_init()--Set up the SSP and direct the SSPFRM
 *                             signal to the EEPROM chip select.
 *                             You must call this before calling
 *                             any other EEPROM driver functions
 *   lcd_eeprom_erase_word()--Erase (set to 0xFFFF) a single EEPROM
 *                            word at the specified address
 *   lcd_eeprom_erase_all()--Erase (set to 0xFFFF) all EEPROM words
 *   lcd_eeprom_lock()--Prevent EEPROM write or erase commands from
 *                      working.
 *   lcd_eeprom_unlock()--Allow EEPROM write or erase commands to work
 *   lcd_eeprom_read()--Return an EEPROM word from a specifed address
 *   lcd_eeprom_block_read()--Read a consecutive block of words from
 *                            EEPROM starting at a specified address
 *                            and return the number of words read.
 *   lcd_eeprom_write()--Write a single EEPROM word at a specifed
 *                       EEPROM address
 *   lcd_eeprom_fill()--Fill the entire EEPROM with a specified data
 *                      value
 *
 * Strategy:
 *  The EEPROM's data format is not quite compatible with the
 *  MICROWIRE mode on the LH7A400 SSP because the EEPROM command word
 *  is too long. We have to transmit 16-bit data during writes, and
 *  we have to read back 16-bit data during reads. We use the SPI mode
 *  with a 16-bit word length. We use SPH==1 so that SSPFRM will
 *  remain asserted for the multi-SSP word write commands, and the 
 *  mult-SSP word read commands. See individual functions for
 *  details.
 *
 *	References:
 *      SHARP_EVB_DISPLAY_BOARD_REV2.pdf
 *      93LC46.pdf (Microchip 1K Microwire(R) EEPROM chip spec).
 *
 * Requires;
 *      ssp_driver.h -- serial communications driver
 *
 *	Revision History:
 *	$Log:   P:/PVCS6_6/archives/LH7A400 (Aruba)/SSP/lh7a400_lcd_evb_eeprom_driver.c-arc  $
 * 
 *    Rev 1.2   Nov 21 2001 11:38:28   KovitzP
 * Added function block comments and revised the 
 * lcd_eeprom_block_read() function to send only as many
 * words as requried.
 * 
 *    Rev 1.1   Nov 14 2001 09:01:44   KovitzP
 * Modified include hierarchy
 * 
 *    Rev 1.0   Nov 12 2001 13:32:10   KovitzP
 * Initial revision.
 * 
 * 
 *	COPYRIGHT (C) 2001 SHARP MICROELECTRONICS OF THE AMERICAS, INC.
 *		CAMAS, WA
 *********************************************************************/
#include "lh7a400_lcd_evb_eeprom_driver.h"

/**********************************************************************
*
* Function: eeprom_busy_poll
*
* Purpose:
*  Following a write or erase, wait for the EEPROM busy signal to
*  go high.
*
* Processing:
*  Following an erase or write command, the EEPROM will signal that 
*  the write or erase operation is complete by transitioning its
*  data output from a 0 to a 1 provided that its chip select is
*  desserted after the write command completes and reasserted 500 ns
*  after the chip select has been deasserted. SSPFRM cannot be
*  directly controlled as GPIO pin. This more complex algorithm
*  results:
*
*  Convert the timeout_in_milliseconds to units of the time it takes
*  to send a single word.
*  Wait for the last SSP transaction to complete.
*  Flush the receive FIFO.
*  Wait approximately 500 ns. This time is not really critical.
*  It can be longer.
*  Write a 0 to the transmit FIFO and then keep writing 
*  0 to the transmit FIFO until the data read back from the 
*  EEPROM is not 0. This keeps the EEPROM's chip select
*  asserted while we wait for the EEPROM data output to transition
*  from 0 to 1.
*  
*
* Parameters:
*  timeout_in_milliseconds: approximate number of milliseconds before
*                           aborting the busy poll operation
*
* Outputs: None
*
* Returns:
*  Return 0 if timed out. Otherwise, return 1.
*
* Notes:
*
**********************************************************************/
static INT_32 eeprom_busy_poll(INT_32 timeout_in_milliseconds)
{
   int i, timeout_in_words;
   
   timeout_in_words = (ssp_get_speed() * 
                       timeout_in_milliseconds) / 
                      (ssp_get_bits_per_word() * 
                       1000);
   /* wait for SSP to be not busy */
   while (ssp_busy() )
      ;

   /* flush the receive FIFO */
   while (ssp_receive_fifo_not_empty() )
      ssp_receive();

   /* 
   assume 10 ns bus speed. Wait at least 500 ns before 
   checking if write is complete
   */
   for (i = 0; i < 50; i++)
      ;
   
   /* keep CS active by keeping data in the transmit buffer */
   ssp_transmit(0);
   do
   {
      ssp_transmit(0);
   } while (timeout_in_words-- && ssp_receive() == 0);

   /* wait for SSP to be not busy */
   while (ssp_busy() )
      ;

   /* flush the receive FIFO */
   while (ssp_receive_fifo_not_empty() )
      ssp_receive();

   /* return success or timeout */
   return timeout_in_words != 0;
}


/**********************************************************************
*
* Function: lcd_eeprom_driver_init
*
* Purpose:
*  Set up the SSP and direct the SSPFRM signal to the EEPROM
*  chip select
*
* Processing:
*  Initialize SSP in SPI mode. Set the bits per word to EE_WORDSIZE,
*  set the speed to EE_BPS. Turn loopback off, Set SPH so that
*  SSPFRM will remain asserted so long as there is data in the
*  SSP transmit FIFO. Set SPO so that data changes on the correct
*  clock edge given the state of SPH. Switch the SSPFRM mux circuit
*  on the CPU board so that SSPFRM will assert the EEPROM chip select
*  Enable and flush the FIFOs.
*
* Parameters: None
*
* Outputs: None
*
* Returns: Nothing
*
* Notes:
*  must call this before calling any other EEPROM driver functions
*
**********************************************************************/
void lcd_eeprom_driver_init(void)
{

   /* set up the SSP for SPI mode, 16-bit word access */
   ssp_init_spi_mode();
   ssp_set_bits_per_word(EE_WORDSIZE);
   ssp_set_speed(EE_BPS);
   ssp_loopback_off();
   ssp_spi_set_sph();	/* allow for continuous mode transmission */
   ssp_spi_set_spo();   /* correct the clock phase */

   /* SSPFRM activates the LCD board's serial EEPROM's Chip Select */
   lh7a400_evb_ssp_frame_eeprom();
   
   /* enable the FIFOs */
   ssp_enable_fifos();
   ssp_flush_fifos();

}

/**********************************************************************
*
* Function: lcd_eeprom_erase_word
*
* Purpose:
*  Erase (set to 0xFFFF) a single EEPROM word at the specified address
*
* Processing:
*  Make sure the SSP is not in use.
*  Flush the receive FIFO
*  Write the erase word command to the transmit FIFO.
*  Poll the EEPROM status until it is not busy anymore.
*
* Parameters:
*  adr:                     The address of the word to erase (0-63)
*  timeout_in_milliseconds: number of milliseconds to wait for erase
*                           operation to complete
*
* Outputs: None
*
* Returns: 
*  0 if timed out.
*  1 if successful, 
*
* Notes:
*  This command will fail if the EEPROM is locked.
*
**********************************************************************/
INT_32 lcd_eeprom_erase_word(INT_32 adr, 
                           INT_32 timeout_in_milliseconds)
{
   /* wait for SSP to be not busy */
   while (ssp_busy() )
      ;
   /* flush the receive FIFO */
   while (ssp_receive_fifo_not_empty() )
      ssp_receive();

   ssp_transmit(EE_ERASE(adr));
   return eeprom_busy_poll(timeout_in_milliseconds);
}

/**********************************************************************
*
* Function: lcd_eeprom_erase_all
*
* Purpose:
*  Erase (set to 0xFFFF) all EEPROM words
*
* Processing:
*  Make sure the SSP is not in use.
*  Flush the receive FIFO
*  Write the erase all command to the transmit FIFO.
*  Poll the EEPROM status until it is not busy anymore.
*
* Parameters: 
*  timeout_in_milliseconds: number of milliseconds to wait for erase
*                           operation to complete
*
* Outputs: None
*
* Returns:
*  0 if timed out.
*  1 if successful, 
*
* Notes:
*  This command will fail if the EEPROM is locked.
*
**********************************************************************/
INT_32 lcd_eeprom_erase_all(INT_32 timeout_in_milliseconds)
{
   /* wait for SSP to be not busy */
   while (ssp_busy() )
      ;

   /* flush the receive FIFO */
   while (ssp_receive_fifo_not_empty() )
		ssp_receive();

   ssp_transmit(EE_ERAL );

   return eeprom_busy_poll(timeout_in_milliseconds);
}

/**********************************************************************
*
* Function: lcd_eeprom_lock
*
* Purpose:
*  Prevent EEPROM write or erase commands from working.
*
* Processing:
*  Wait for all pending SSP transmissions to complete. Transmit
*  the lock command.
*
* Parameters: None
*