topic PHY device not responding to MDIO in Kinetis Microcontrollers

PHY device not responding to MDIO

chaitannyamahat — Sat, 27 Dec 2014 16:21:39 GMT

Hello Everyone,

I am using the K60DN512 device with 8720A PHY IC. I have written a simple program to communicate with the PHY IC. I have checked it on logic analyser and I am not getting any response from the PHY device. What can be possible causes.

Configuration of PHY device straps.

PHYAD[0]: Pulled low.

MODE[2:0] : 011 100Base-TX Full Duplex. Auto-negotiation disabled. CRS is active during Receive.

MDIO : Pulled high.

MDC: 1 Mhz.

I am using the processor expert generated code. So in that case there shouldn't be any error. What can be the possible reason for communication failure. The value is either 0 or 0xFFFF.

main(){

MAChandler = mac_Init(NULL);

Bit1_Init(NULL);

uint16_t id = 0;

uint16_t value = 0;

uint16_t timeout = 0;

uint16_t count = 0;

uint8_t sfr = 0;

const uint8_t netifLINK_DELAY = 3;

do {

mii_read(id, PHY_PHYIDR1, &value);

count++;

} while (value == 0xffff);

do {

value = 0xffff;

mii_read(id, sfr, &value);

if (value != 0xffff)

sfr++;

count++;

} while (sfr <= 0x1F);

uint16 config;

do {

config = 0x2200;

mii_write(id, PHY_BMCR, config);

uint16_t i, j;

for (i = 0; i < 0xFF; i++)

for (j = 0; j < 0xFFFF; j++)

;

mii_read(id, PHY_BMCR, &value);

count++;

} while (value != config);

}

int mii_write(int phy_addr, int reg_addr, uint16_t data) {

int timeout;

/* Clear the MII interrupt bit */ENET_EIR /*(ch)*/= ENET_EIR_MII_MASK;

/* Initiatate the MII Management write */ENET_MMFR /*(ch)*/=

0 | ENET_MMFR_ST(0x01) | ENET_MMFR_OP(0x01) | ENET_MMFR_PA(phy_addr)

| ENET_MMFR_RA(reg_addr) | ENET_MMFR_TA(0x02)

| ENET_MMFR_DATA(data);

/* Poll for the MII interrupt (interrupt should be masked) */

for (timeout = 0; timeout < MII_TIMEOUT; timeout++) {

if (ENET_EIR /*(ch)*/& ENET_EIR_MII_MASK)

break;

}

if (timeout == MII_TIMEOUT)

return 1;

/* Clear the MII interrupt bit */ENET_EIR /*(ch)*/= ENET_EIR_MII_MASK;

return 0;

}

/********************************************************************/

/*!

* \brief Read a value from a PHY's MII register.

* \param phy_addr Address of the PHY

* \param reg_addr Address of the register in the PHY

* \param data Pointer to location were read data will be stored

* \return 0 if write is successful; 1 if write times out

* mii_read() polls for the FEC's MII interrupt event (which should

* be masked from the interrupt handler) and clears it. If after a

* suitable amount of time the event isn't triggered, a non-zero value

* is returned.

int mii_read(int phy_addr, int reg_addr, uint16_t *data) {

int timeout;

/* Clear the MII interrupt bit */ENET_EIR /*(ch)*/= ENET_EIR_MII_MASK;

Bit1_SetVal(NULL); // Indication that the MDIO transfer is about to begin.

/* Initiatate the MII Management read */ENET_MMFR /*(ch)*/= 0

| ENET_MMFR_ST(0x01) | ENET_MMFR_OP(0x2) | ENET_MMFR_PA(phy_addr)

| ENET_MMFR_RA(reg_addr) | ENET_MMFR_TA(0x02);

/* Poll for the MII interrupt (interrupt should be masked) */

for (timeout = 0; timeout < MII_TIMEOUT; timeout++) {

if (ENET_EIR /*(ch)*/& ENET_EIR_MII_MASK){

Bit1_ClrVal(NULL); // Indication that the MDIO transfer is complete.

break;

}

if (timeout == MII_TIMEOUT)

return 1;

/* Clear the MII interrupt bit */ENET_EIR /*(ch)*/= ENET_EIR_MII_MASK;

uint16_t test = ENET_MMFR /*(ch)*/& 0x0000FFFF;

*data = ENET_MMFR /*(ch)*/& 0x0000FFFF;

return 0;

}

Re: PHY device not responding to MDIO

Kan_Li — Thu, 08 Jan 2015 07:50:14 GMT

Hi,

Are you sure you are using the PE generated code? after I checked the Ethernet demo from CW 10.6, the generated driver is different from what you show, for example, the mii_read() should be the following:

** ===================================================================

** Method : ETH_ReadMII (component Ethernet_LDD)

/*!

** @brief

** Initiates a MII register read operation. The end of the

** operation is signalized by the OnMIIFinished event in the

** interrupt mode or by the GetMIIResult method in the polled

** mode. The value of the register is returned by the

** GetMIIResult method. This method is available only if

** management bus is enabled.

** @param

** DeviceDataPtr - Pointer to device data

** structure.

** @param

** PhyAddr - PHY device address.

** @param

** RegAddr - MII register address.

** @return

** -

** Error code, possible values:

** ERR_OK - OK

** ERR_SPEED - The component does not work in

** the active clock configuration

** ERR_DISABLED - The component is disabled

/* ===================================================================*/

LDD_TError ETH_ReadMII(LDD_TDeviceData *DeviceDataPtr, uint8_t PhyAddr, uint8_t RegAddr)

{

ETH_TDeviceData *DeviceDataPrv = (ETH_TDeviceData*)DeviceDataPtr;

(void)DeviceDataPrv; /* Supress unused variable warning if needed */

ENET_PDD_SendMIIFrame(ENET_BASE_PTR, ENET_PDD_MII_READ, PhyAddr, RegAddr, 0U);

return ERR_OK;

}

#define ENET_PDD_SendMIIFrame(PeripheralBase, OpCode, PhyAddr, RegAddr, Data) ( \

ENET_MMFR_REG(PeripheralBase) = \

(uint32_t)(( \

(uint32_t)((uint32_t)0x1U << ENET_MMFR_ST_SHIFT)) | (( \

(uint32_t)(OpCode)) | (( \

(uint32_t)((uint32_t)(PhyAddr) << ENET_MMFR_PA_SHIFT)) | (( \

(uint32_t)((uint32_t)(RegAddr) << ENET_MMFR_RA_SHIFT)) | (( \

(uint32_t)((uint32_t)0x2U << ENET_MMFR_TA_SHIFT)) | ( \

(uint32_t)(Data))))))) \

)

and have you configured the pins for MDIO and MDC, for the device of K60N512, they are PTB0 and PTB1.

Please kindly refer to "C:\Freescale\CW MCU v10.6\MCU\CodeWarrior_Examples\Processor_Expert\Kinetis\TWR-K60N512\Ethernet" for more details.

Hope that helps,

Have a great day,
Kan

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