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USB Superspeed Peripherals

Contributor

Dear Sir,

I add a I2C mux to extend CX3 I2C bus , but it doesn't work, I cannot see any I2C wave from the output of PCA9540B, I also call read channel status, it seems no any change. status return from write and raed API seem ok !

only two commands are supported, one is write channel (xxxxxB2B1B0), the other is read channel status(xxxxxB2B1B0).

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The following is my code,  are preamble filled correctly?  any comments will  be appreciated!

/*

* pca9540b.c

*

*  Created on: 2017年9月19日

*      Author: lenovo

*/

#include <cyu3error.h>

#include <cyu3i2c.h>

#include <cyu3os.h>

//#include <cyu3types.h>

//#include "pca9540b.h"

#define PCA9540B_IIC_ADDR  0x70

const uint8_t PCA9540B_IIC_WRITEADDR = 0xe0;//PCA9540B_IIC_ADDR << 1;

const uint8_t PCA9540B_IIC_READADDR = 0xe1;//(PCA9540B_IIC_ADDR << 1)|1;

// control byte true table

// D7  D6  D5  D4  D3  D2  D1  D0     channel

// x   x   x   x   x   0   x   x      no channel selected

// x   x   x   x   x   1   0   0      CH0 enable

// x   x   x   x   x   1   0   1      CH1 enable

// x   x   x   x   x   1   1   x      no channel selected

// 0   0   0   0   0   0   0   0      no channel selected;power-up default state

const uint8_t PCA9540B_CH[3] =

{

     0x04, // channel 0

     0x05, // channel 1

     0x00 // both of channels 0,1 are disable

};

uint32_t pca9540b_SetCh(uint32_t ch)

{

     CyU3PReturnStatus_t status = CY_U3P_SUCCESS;

     CyU3PI2cPreamble_t preamble;

     uint8_t data[32] ={0};                                              //just for api calling,if NULL is called,0x41 will be return by CyU3PI2cTransmitBytes()

     static uint32_t ch_1 = 2;                                         // PCA9540B_CH[2] = 0x00, all are disable

     if(ch > 2) return CY_U3P_ERROR_BAD_ARGUMENT;           // only 0,1 channel is permitted

     if ( ch == ch_1) return CY_U3P_SUCCESS;                               // no real switch action

     preamble.buffer[0] = PCA9540B_IIC_WRITEADDR;

     preamble.buffer[1] = PCA9540B_CH[ch];

     preamble.length = 2;

     preamble.ctrlMask = 0x0000;

  

     status = CyU3PI2cTransmitBytes(&preamble,data,0,0);

     if(status != CY_U3P_SUCCESS)

           CyU3PDebugPrint(4,"\n\rErr: pca9540b_SetCh failed! status = %x\n\r",status);

     else

           ch_1 = ch;

     return status;

}

// read channel configuration

uint32_t pca9540b_GetCh(uint8_t *ch_status)

{

     CyU3PReturnStatus_t status = CY_U3P_SUCCESS;

     CyU3PI2cPreamble_t preamble;

     preamble.buffer[0] = PCA9540B_IIC_READADDR;

     preamble.length = 1;

     preamble.ctrlMask = 0x0000;

     status = CyU3PI2cReceiveBytes(&preamble,ch_status,1,0); // only one byte read

     CyU3PThreadSleep(1);

     if (status != CY_U3P_SUCCESS)

        CyU3PDebugPrint(4,"\n\rErr: pca9540b_GetCh failed! status = %x\n\r",status);

     return status;

}

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1 Solution
Contributor

Dear Sir,

I just put control byte in data buffer, other than in preamble.buffer , then it works fine.

     preamble.buffer[0] = PCA9540B_IIC_WRITEADDR;

     //preamble.buffer[1] = PCA9540B_CH[ch];

     //preamble.length = 2;

     preamble.length = 1;

     preamble.ctrlMask = 0x0000;

 

     data[0] = PCA9540B_CH[ch];     // fill control byte in data section and send count is 1

     status = CyU3PI2cTransmitBytes(&preamble,data,1,0);

it seems DATA section shouldn't be NULL.

Thanks.

David

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2 Replies
Employee

Please provide a waveform of the I2C bus between FX3 and PCA9540B

Regards,

Noriaki

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Contributor

Dear Sir,

I just put control byte in data buffer, other than in preamble.buffer , then it works fine.

     preamble.buffer[0] = PCA9540B_IIC_WRITEADDR;

     //preamble.buffer[1] = PCA9540B_CH[ch];

     //preamble.length = 2;

     preamble.length = 1;

     preamble.ctrlMask = 0x0000;

 

     data[0] = PCA9540B_CH[ch];     // fill control byte in data section and send count is 1

     status = CyU3PI2cTransmitBytes(&preamble,data,1,0);

it seems DATA section shouldn't be NULL.

Thanks.

David

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