topic Re: SPI->EEPROM in Kinetis Microcontrollers

SPI->EEPROM

josephchen — Tue, 16 Dec 2014 08:16:13 GMT

I'm using MQX 4.1.1 and trying to connect to a SPI EEPROM by MK63 MCU. The part number of EEPROM I'm using is CAT25512HU5I−GT3. I use the spi example, but everytime I get wrong data when I try to read from EEPROM. I have detect the signals by oscilloscope. For the writing, it shows exactly what I transfer. However, when I read, it shows one-byte READ instruction with 16-bit address, but it always has an extra byte 0xFF sent out after the three bytes. Is it possible to be the problem in its driver?

Re: SPI->EEPROM

soledad — Fri, 09 Jan 2015 20:54:30 GMT

Hi Joseph,

Are you using a Freescale board???

Which BSP are you using???

Have a great day,
Sol

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Re: SPI->EEPROM

josephchen — Sat, 10 Jan 2015 00:22:14 GMT

I'm actually using a customized board with K63 MCU and a SPI EEPROM connected. There's another IOExpander connected via same SPI channel, and they share the same SS line. Therefore, there's a NOT gate added to the SS line between MCU and EEPROM. I have set the CS to GPIO and select the device by a callback function.The BSP is modified from K61 BSP, and I'm pretty sure the BSP is set correctly. I also have the same customized board but with K61 MCU, and it encounters the same problem.

Re: SPI->EEPROM

josephchen — Sat, 10 Jan 2015 00:24:41 GMT

My callback function :

static _mqx_int set_CS (uint32_t cs_mask, void *user_data)

{

LWGPIO_STRUCT_PTR spigpio = (LWGPIO_STRUCT_PTR)user_data;

static boolean chip_selected = FALSE;

if (cs_mask)

{

if (!chip_selected)

{

if (cs_mask & SPI_EEPROM_CS)

{

if (lwgpio_get_value(spigpio) == LWGPIO_VALUE_HIGH)

{

lwgpio_set_value(spigpio, LWGPIO_VALUE_LOW);

_dspi_time_delay(5);

}

lwgpio_set_value(spigpio, LWGPIO_VALUE_HIGH);

_dspi_time_delay(5);

}

else /* IOExpander “ispi1 :1:” */

{

if (lwgpio_get_value(spigpio) == LWGPIO_VALUE_LOW)

{

lwgpio_set_value(spigpio, LWGPIO_VALUE_HIGH);

_dspi_time_delay(5);

}

lwgpio_set_value(spigpio, LWGPIO_VALUE_LOW);

_dspi_time_delay(5);

}

chip_selected = TRUE;

}

else

{

chip_selected = FALSE;

_dspi_time_delay(5);

lwgpio_toggle_value(spigpio);

}

return MQX_OK;

}

As you can see, I specially add 5 us delay between CS and SCLK.