ZHCSEF7G December 2014 – February 2019 TPS659037
PRODUCTION DATA.
Software can enable periodic conversions to compare one or two channels with a predefined threshold level. Software must select one or two channels with the GPADC_AUTO_SELECT register and thresholds and polarity with the GPADC_THRES_CONV0_LSB, GPADC_THRES_CONV0_MSB,
GPADC_THRES_CONV1_LSB, and GPADC_THRES_CONV1_MSB registers. In addition, software must select the conversion interval with the GPADC_AUTO_CTRL register and enable the periodic conversion with the AUTO_CONV0_EN and AUTO_CONV1_EN bits. There is no need to enable the GPADC separately. The control logic enables and disables the GPADC automatically to save power. When AUTO mode is the only conversion enabled, do not use the AUTO_CONV0_EN and AUTO_CONV1_EN bits to disabled the conversion. Instead, force the state machine of the GPADC on by setting the GPADC_CTRL1. GPADC_FORCE bit = 1, then shutdown the GPADC AUTO conversion using GPADC_AUTO_CTRL.SHUTDOWN_CONV[01] = 0. Wait 100 µs before disabling the GPADC state machine by setting GPADC_CTRL1. GPADC_FORCE bit = 0. The latest conversion result is always stored in the GPADC_AUTO_CONV0_LSB, GPADC_AUTO_CONV0_MSB,
GPADC_AUTO_CONV1_LSB, and GPADC_AUTO_CONV1_MSB registers. All selected channels are queued and converted from channel 0 to 7. The first (lower) converted channel results is placed in the GPADC_AUTO_CONV0 register and the second one is placed in the GPADC_AUTO_CONV1 register. Therefore, TI recommends putting the lower channel to convert in AUTO_CONV0_SEL and the higher channel to convert in AUTO_CONV1_SEL.
If the conversion result triggers the threshold level, an INT interrupt is generated and the conversion result is stored. If the interrupt is not cleared or the results are not read before another auto-conversion is completed, then the registers store only the latest results, discarding the previous ones. The auto conversion is never stopped by an uncleared interrupt or unread registers.
Programming the triggering of the threshold level can also generate shutdown. This is available for CONV0 and CONV1 channels independently and is enabled with the SHUTDOWN bits in the GPADC_AUTO_CTRL register. During SLEEP and OFF modes, only channels from 0 to 10 can be converted. For channels 12 and 13, conversion is possible in sleep if thermal sensor is not disabled.