COP8AME9_14 Datasheet, PDF (65/102 Pages) Texas Instruments – COP8AME9 8-Bit CMOS Flash Microcontroller with 8k Memory, Dual Op Amps, Virtual EEPROM, Temperature Sensor, 10-Bit A/D and Brownout Reset

COP8AME9, COP8ANE9
www.ti.com
SNOS930F – MARCH 2001 – REVISED MARCH 2013
The amplifier offset can drift slightly as the temperature changes. For example, over the entire temperature range
of −40°C to +125°C, the drift could be typically 2 mV. If the user application is in a constantly changing
temperature, and this offset drift is a problem, it is recommended that the amplifier be retrimmed periodically, or
before critical measurements. The on-chip temperature sensor could also be used to measure temperature
variations and determine whether retrimming of the offset is necessary.
Figure 30. Offset Trim Configuration when TRIM = 1
The procedure to trim both the N channel pair and P channel pair are listed below. Steps 1–14 trim the N
channel pair and steps 15–30 trim the P channel pair.
1. Set the TRIM bit = 1 in the ADGAIN register to configure the amplifier.
2. Load C0h into the AMPTRMN register to select VREFN and the no-trim value.
3. Wait 1.05 ms for the amplifier to settle.
4. Load 01h into ENAD to perform an A/D Conversion.
5. Store the result registers.
6. If the three most significant bits of the result are all ones, go to step 8.
– Else, if the three most significant bits are all zeros, go to step 7.
– Else, goto step 15.
7. Set ATRMN6 = 0
8. First time through loop, set ATRMN5 = 1
– Second time through loop, set ATRMN4 = 1
– Third time through loop, set ATRMN3 = 1
– Fourth time through loop, set ATRMN2 = 1
– Fifth time through loop, set ATRMN1 = 1
– Sixth time through loop, set ATRMN0 = 1
– Seventh time through loop, go to step 15.
9. Wait 1.05 ms for the amplifier to settle.
10. Load 01h into ENAD to perform an A/D Conversion.
11. Store the result registers.
12. If the three most significant bits of the result are all ones and ATRMN6 = 1, go to step 8.
– Else, if the three most significant bits are all zeros and ATRMN6 = 1, go to step 13.
– Else, if the three most significant bits are all ones and ATRMN6 = 0, go to step 13.
– Else, if the three most significant bits are all zeros and ATRMN6 = 0, go to step 8.
– Go to step 15.
13. First time through loop, set ATRMP5 = 0
– Second time through loop, set ATRMP4 = 0
– Third time through loop, set ATRMP3 = 0
– Fourth time through loop, set ATRMP2 = 0
– Fifth time through loop, set ATRMP1 = 0
– Sixth time through loop, set ATRMP0 = 0
14. Go to step 8.
15. Reset CALN bit = 0, but leave ATRMN6 : 0 unchanged.
16. Load C0h into the AMPTRMP register to select VREFP and the no-trim value.
17. Wait 1.05 ms for the amplifier to settle.
18. Load 01h into ENAD to perform an A/D Conversion.
19. Store the result registers.
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