TM4C1294KCPDT: Excessive IO sinking current causes the monolithic heating

Cherry Zhou

Part Number: TM4C1294KCPDT
Other Parts Discussed in Thread: ADC1175

Hi team,

Here's an issue from the customer may need your help:

Scenario: Configure TM4C1294KCPDT enabled EPI as hostbus16, EPI0S0 to EPI0S15 as data lines connected to buffer 16t245 (D0-D8 of ADC on the other side of 245). EPI0S30 is configured as CS and is connected directly to the ADC1175 clock.(hw connection issue: whis is a requirement timing that the customer can find that corresponds to ADC)

Issue: The 245 output is pulled low with some pulses. If ADC only outputs a high signal (for example, 0xff), it can be seen that the output high of 245 is pulled down to 2.7V (same as the magnitude of the high in the test waveform) and at this time the monolithic is heating up.

This does not occur if the EPI module is left on, except that the epi0s0 through spi0s15 are all canceled and configured as GPIO input. The customer think this might be related to the configuration of the EPI, but are there other possible causes?

Note: the data is received correctly and the corresponding data is correct.

The EPI module initialization code is as follows:

//Initialize the EPI interface 
static inline void ADCInterfaceInit()
{
    //The IO is configured as the corresponding signal function is already in the pinmux 
    //The interface here is the EPI 
    MAP_SysCtlPeripheralEnable(SYSCTL_PERIPH_EPI0);
    while(!SysCtlPeripheralReady(SYSCTL_PERIPH_EPI0));
 
    //EPIDividerSet(EPI0_BASE, 10);//
    EPIModeSet(EPI0_BASE,EPI_MODE_HB16);
    //Configure the host bus: Address is not muxed 
    EPIConfigHB16Set(EPI0_BASE,EPI_HB16_MODE_ADDEMUX|EPI_HB16_CSCFG_CS,0);
    EPIAddressMapSet(EPI0_BASE,EPI_ADDR_PER_BASE_A|EPI_ADDR_PER_SIZE_256B);//Set up the address map (it seems like it's not working here), follow the instructions in the manual to set up a baseA of size 256B, and once the address is set, you can access external memory or peripherals through the map set here. 
    while(HWREG(EPI0_BASE + EPI_O_STAT) & EPI_STAT_INITSEQ);//Wait for the configuration to complete 
}

The following figure shows the signal on a data line configured as an epi0s0-s15: Red is the chip select (connected to ADCCLK) and yellow is the data line signal measured at a monolithic pin: