Part Number: ADS7128
Tool/software:
Hello.
I'm fighting with the ADS7128 I2C ADC, and I'm unable to get the RMS to work. Reading Recent value works for me (on channels 0-2 which I use).
I tried to look for some example, but on github there is only .h file (which is even missing RMS_DONE and RMS_EN definitions) and no C code.
For faster testing, I'm using Python now, but the flag RMS_DONE (0x10) in SYSTEM_STATUS register is never 1.
Here is the Python example:
Thank you
from smbus2 import SMBus
from ads7128_defs import *
import time
bus = SMBus(1)
# reset for sure
bus.write_i2c_block_data(ADSI2C_ADDR, WRITE_SR_CODE, [GENERAL_CFG_REG, RST])
time.sleep(1)
# manual selection of channel
bus.write_i2c_block_data(ADSI2C_ADDR, WRITE_SR_CODE, [CHANNEL_SEL_REG, 0])
# Enable DC SUB in RMS
bus.write_i2c_block_data(ADSI2C_ADDR, SET_BIT_CODE, [RMS_CFG_REG, RMS_DC_SUB])
while True:
# enable RMS
bus.write_i2c_block_data(ADSI2C_ADDR, SET_BIT_CODE, [GENERAL_CFG_REG, RMS_EN])
# wait for RMS done
rmsState = 0
while rmsState == 0:
bus.write_byte_data(ADSI2C_ADDR, READ_SR_CODE, SYSTEM_STATUS_REG)
rmsState = bus.read_byte(ADSI2C_ADDR) & RMS_DONE
# read Recent ADC value, this works, so conversion should be started
bus.write_byte_data(ADSI2C_ADDR, READ_MR_CODE, RECENT_CH0_LSB_REG)
blsb = bus.read_i2c_block_data(ADSI2C_ADDR, 0, 2)
print("recent: " + str(blsb))
print("rmsState: " + str(rmsState))
time.sleep(1)
bus.write_byte_data(ADSI2C_ADDR, READ_MR_CODE, RMS_LSB_REG)
rms = bus.read_i2c_block_data(ADSI2C_ADDR, 0, 2)
print("rms: " + str(rms))
time.sleep(1)
