SLAZ357J October 2012 – May 2021 MSP430FE427
ESP Module
Functional
Suspending the ESP430 activity
Due to timing violations between the ESP CPU and the MSP430 CPU, the SD16 converters are not switched off correctly if the ESP CPU is set into suspend mode immediately after the ESP CPU is checked for idle mode. This leads to an higher current consumption in low-power modes.
Implement an additional wait loop of 16 clock cycles between checking the ESP for idle mode and set the ESP CPU into suspend mode.
while ((RET0 & 0x8000) != 0); // Wait for Idle mode
// wait 16 clocks to exclude timing violations between MSP430 CPU
// and ESP CPU
_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();--
_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();_NOP();
// Shut down ESP (set Embedded Signal Processing into "Suspend" mode)
// ensure that it is not in measurement or calibration mode,
if ((RET0 & 0x8000) == 0)
{
ESPCTL |= 0x08 + ESPSUSP; // Set ESP into Suspend Mode
// incl. Bug Fix for Suspend Mode
}