Hi,everyone:
we use the DM648 as a slave to communicate with an ARM through the I2C, and the rate is 100kbps. However, sometimes the I2C of DM648 will not send the ACK bit to the ARM(Figure 1 below). this problem is very serious when arm send data to DM648 often(for example , every300ms). what causes this and how to solve it?
Figure1 the wave on the SCL and SDA(yellow--SCL, blue--SDA)
Below is our configuration:
PSP_I2cConfig I2C_devParams =
{PSP_OPMODE_INTERRUPT, //interrupt mode
0x5D, //own address
8,//Number of bits/byte to be sent/received
100000,//I2C Bus Frequency. 100kbps
108000000,//module input clock freq. 108MHz
FALSE,//7bits/10bits Addressing mode
FALS//Digital Loop Back(DLB)mode enabled
}; //this parameter is used in the tcf file
below in our program：
1)create：
GIO_Handle i2cHandle = NULL;
i2cHandle = GIO_create("/I2C0",IOM_INOUT,&status,NULL,&gioAttrs);
if(NULL == i2cHandle)
{
//restart
}
2) read：
{
PSP_i2cDataParam buf;
size_t size = 1;
Int retCode = 0;
Uint8 *inputbuf = NULL;
inputbuf = (Uint8 *)MEM_calloc(extHeap,256,64);
if(NULL == inputbuf)
{
//error
}
buf.i2cTrans.buffer = inputbuf;
buf.i2cTrans.bufLen = 256;
buf.i2cTrans.flags = PSP_I2C_READ|PSP_I2C_IGNORE_BUS_BUSY;
buf.i2cTrans.param = NULL;
buf.timeout = SYS_FOREVER;
size = 1u;
retCode = GIO_read(i2cHandle,&buf,&size);
}
besides, we use pspdriver_1_10_00_09，and bios_5_31_02
