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MSPM0L1306: ADC12 sequencing interference between channels

Sebastien Grenier
Prodigy 100 points

Part Number: MSPM0L1306
Other Parts Discussed in Thread: LP-MSPM0C1104

Tool/software:

I did add more ADC channels in sequence mode.
I see that the channels have an influence together.

I mean that the voltage on the channel MEM0 has an influence on the voltage sampled on the next channel let say in MEM1.

Is there a way to avoid the cross talk between "sequenced" by the sequencer analog channels... Delay??? Sampling time???


  • 0
    TI__Mastermind 40195 points

    Can you share more information like test result and test code to show how "the voltage on the channel MEM0 has an influence on the voltage sampled on the next channel let say in MEM1"?

    Can you try to increase the sampling time to see if the result will change?

  • 0 in reply to Eason Zhou
    Prodigy 100 points

    Hi Eason,
    Yes I tried to increase the sampling time with no good results.
    The code I have is based on this example here :

    https://dev.ti.com/tirex/explore/node?node=A__ANq7v2KAreeLhjdIeWm9bA__MSPM0-SDK__a3PaaoK__LATEST&placeholder=true&search=adc

    Here is the code I have and the uart result :

    Fullscreen uart result.txt Download 
    openocd.exe "-f" "BTH STM32L431RCT6 Debug.cfg" "-s" "D:/STM32/BTH STM32L431RCT6" "-s" "C:/ST/STM32CubeIDE_1.15.1/STM32CubeIDE/plugins/com.st.stm32cube.ide.mcu.debug.openocd_2.2.100.202406131243/resources/openocd/st_scripts" "-s" "C:/ST/STM32CubeIDE_1.15.1/STM32CubeIDE/plugins/com.st.stm32cube.ide.mpu.debug.openocd_2.1.200.202405171325/resources/openocd/st_scripts" "-c" "gdb_report_data_abort enable" "-c" "gdb_port 3333" "-c" "tcl_port 6666" "-c" "telnet_port 4444"

openocd -f interface/stlink-v2.cfg -f target/lpc11xx.cfg -c 'adapter speed 4000' -c init -c 'reset halt' -c 'sleep 10' -c 'flash write_image erase out/main.elf 0 elf' -c 'reset halt' -c 'resume' -c shutdownCH4:2389
CH2:1438
CH3:790
CH4:2389
CH2:1444
CH3:792
CH4:2388
CH2:1441
CH3:793
CH4:2389
CH2:1440
CH3:792
CH4:2388
CH2:1440
CH3:791
CH4:2390
CH2:1437
CH3:792
CH4:2390
CH2:1443
CH3:792
CH4:2388
CH2:1443
CH3:792
CH4:2389
CH2:1446
CH3:792
CH4:2389
CH2:1441
CH3:790
CH4:2389
CH2:1442
CH3:789
CH4:2388
CH2:1440
CH3:791
CH4:2399
CH2:1446
CH3:792
CH4:2389
CH2:1438
CH3:790
CH4:2388
CH2:1432
CH3:790
CH4:2388
CH2:1437
CH3:792
CH4:2389
CH2:1436
CH3:793
CH4:2389
CH2:1433
CH3:791
CH4:2388
CH2:1431
CH3:790
CH4:2389
CH2:1434
CH3:790
CH4:2390
CH2:1433
CH3:790
CH4:2389
CH2:1432
CH3:791
CH4:2389
CH2:1429
CH3:790
CH4:2389
CH2:1434
CH3:791
CH4:2389
CH2:1428
CH3:791
CH4:2388
CH2:1426
CH3:791
CH4:2388
CH2:1429
CH3:791
CH4:2388
CH2:1425
CH3:791
CH4:2389
CH2:1429
CH3:790
CH4:2388
CH2:1427
CH3:791
CH4:2406
CH2:1437
CH3:792
CH4:2408
CH2:1438
CH3:791
CH4:2387
CH2:1423
CH3:791
CH4:2388
CH2:1432
CH3:791
CH4:2387
CH2:1430
CH3:791
CH4:2388
CH2:1426
CH3:791
CH4:2388
CH2:1430
CH3:790
CH4:2389
CH2:1428
CH3:790
CH4:2388
CH2:1428
CH3:791
CH4:2389
CH2:1428
CH3:791
CH4:2388
CH2:1434
CH3:790
CH4:2388
CH2:1429
CH3:790
CH4:2388
CH2:1430
CH3:790
CH4:2390
CH2:1431
CH3:790
CH4:2387
CH2:1431
CH3:792
CH4:2408
CH2:1444
CH3:790
CH4:2388
CH2:1432
CH3:790
CH4:2389
CH2:1435
CH3:790
CH4:2388
CH2:1437
CH3:790
CH4:2388
CH2:1432
CH3:789
CH4:2389
CH2:1430
CH3:789
CH4:2388
CH2:1438
CH3:789
CH4:2388
CH2:1438
CH3:791
CH4:2389
CH2:1421
CH3:791
CH4:2388
CH2:1446
CH3:790
CH4:2389
CH2:1446
CH3:789
CH4:2389
CH2:1444
CH3:790
CH4:2388
CH2:1438
CH3:790
CH4:2388
CH2:1439
CH3:790
CH4:2389
CH2:1452
CH3:790
CH4:2388
CH2:1442
CH3:791
CH4:2389
CH2:1430
CH3:792
CH4:2389
CH2:1457
CH3:791
CH4:2399
CH2:1450
CH3:793
CH4:2387
CH2:1444
CH3:790
CH4:2388
CH2:1427
CH3:785
CH4:2387
CH2:1422
CH3:780
CH4:2388
CH2:1412
CH3:777
CH4:2388
CH2:1408
CH3:777
CH4:2388
CH2:1412
CH3:778
CH4:2388
CH2:1416
CH3:783
CH4:2389
CH2:1419
CH3:790
CH4:2389
CH2:1425
CH3:800
CH4:2389
CH2:1434
CH3:815
CH4:2391
CH2:1473
CH3:828
CH4:2391
CH2:1454
CH3:832
CH4:2391
CH2:1458
CH3:840
CH4:2392
CH2:1474
CH3:847
CH4:2391
CH2:1476
CH3:848
CH4:2393
CH2:1470
CH3:849
CH4:2392
CH2:1470
CH3:850
CH4:2410
CH2:1466
CH3:851
CH4:2392
CH2:1424
CH3:849
CH4:2392
CH2:1426
CH3:847
CH4:2392
CH2:1424
CH3:846
CH4:2392
CH2:1423
CH3:845
CH4:2392
CH2:1406
CH3:842
CH4:2391
CH2:1396
CH3:838
CH4:2392
CH2:1389
CH3:834
CH4:2391
CH2:1377
CH3:831
CH4:2391
CH2:1376
CH3:828
CH4:2390
CH2:1376
CH3:825
CH4:2390
CH2:1385
CH3:823
CH4:2390
CH2:1387
CH3:821
CH4:2390
CH2:1385
CH3:821
CH4:2409
CH2:1389
CH3:826
CH4:2411
CH2:1398
CH3:833
CH4:2390
CH2:1384
CH3:841
CH4:2393
CH2:1375
CH3:854
CH4:2393
CH2:1394
CH3:876
CH4:2401
CH2:1453
CH3:1050
CH4:2427
CH2:1441
CH3:1414
CH4:2433
CH2:1454
CH3:1487
CH4:2435
CH2:1478
CH3:1502
CH4:2438
CH2:1481
CH3:1548
CH4:2438
CH2:1492
CH3:1568
CH4:2444
CH2:1497
CH3:1659
CH4:2450
CH2:1502
CH3:1740
CH4:2452
CH2:1511
CH3:1746
CH4:2438
CH2:1526
CH3:1516
CH4:2449
CH2:1535
CH3:1411
CH4:2433
CH2:1529
CH3:1460
CH4:2430
CH2:1539
CH3:1429
CH4:2430
CH2:1538
CH3:1442
CH4:2432
CH2:1540
CH3:1479
CH4:2428
CH2:1539
CH3:1384
CH4:2424
CH2:1538
CH3:1344
CH4:2425
CH2:1536
CH3:1348
CH4:2432
CH2:1527
CH3:1506
CH4:2454
CH2:1525
CH3:1857
CH4:2479
CH2:1516
CH3:2253
CH4:2498
CH2:1521
CH3:2384
CH4:2495
CH2:1499
CH3:2424
CH4:2507
CH2:1464
CH3:2641
CH4:2512
CH2:1448
CH3:2836
CH4:2549
CH2:1427
CH3:3268
CH4:2489
CH2:1402
CH3:2217
CH4:2401
CH2:1363
CH3:916
CH4:2405
CH2:1351
CH3:854
CH4:2392
CH2:1338
CH3:837
CH4:2392
CH2:1331
CH3:830
CH4:2390
CH2:1345
CH3:825
CH4:2390
CH2:1365
CH3:827
CH4:2390
CH2:1439
CH3:824
CH4:2390
CH2:1441
CH3:822
CH4:2392
CH2:1501
CH3:825
CH4:2391
CH2:1467
CH3:827
CH4:2390
CH2:1334
CH3:825
CH4:2390
CH2:1303
CH3:822
CH4:2391
CH2:1278
CH3:823
CH4:2390
CH2:1280
CH3:822
CH4:2391
CH2:1360
CH3:823
CH4:2389
CH2:1288
CH3:823
CH4:2391
CH2:1298
CH3:819
CH4:2390
CH2:1314
CH3:822
CH4:2390
CH2:1330
CH3:824
CH4:2408
CH2:1367
CH3:826
CH4:2411
CH2:1380
CH3:826
CH4:2390
CH2:1382
CH3:825
CH4:2391
CH2:1386
CH3:825
CH4:2389
CH2:1392
CH3:826
CH4:2569
CH2:1388
CH3:3684
CH4:2579
CH2:1400
CH3:3715
CH4:2579
CH2:1430
CH3:3721
CH4:2580
CH2:1422
CH3:3727
CH4:2580
CH2:1431
CH3:3728
CH4:2579
CH2:1439
CH3:3728
CH4:2579
CH2:1397
CH3:3725
CH4:2580
CH2:1384
CH3:3721
CH4:2580
CH2:1399
CH3:3720
CH4:2578
CH2:1415
CH3:3716
CH4:2599
CH2:1416
CH3:3714
CH4:2579
CH2:1414
CH3:3711
CH4:2577
CH2:1416
CH3:3708
CH4:2578
CH2:1425
CH3:3704
CH4:2551
CH2:1438
CH3:2325
CH4:2396
CH2:1444
CH3:871
CH4:2392
CH2:1457
CH3:827
CH4:2390
CH2:1451
CH3:814
CH4:2389
CH2:1454
CH3:811
CH4:2390
CH2:1457
CH3:807
CH4:2390
CH2:1470
CH3:805
CH4:2389
CH2:1455
CH3:805
CH4:2390
CH2:1430
CH3:807
CH4:2390
CH2:1436
CH3:806
CH4:2389
CH2:1446
CH3:806
CH4:2390
CH2:1448
CH3:805
CH4:2390
CH2:1440
CH3:806
CH4:2576
CH2:1425
CH3:3741
CH4:2592
CH2:1437
CH3:3743
CH4:2580
CH2:1423
CH3:3735
CH4:2580
CH2:1425
CH3:3730
CH4:2579
CH2:1430
CH3:3722
CH4:2580
CH2:1428
CH3:3717
CH4:2578
CH2:1425
CH3:3713
CH4:2579
CH2:1430
CH3:3713
CH4:2578
CH2:1432
CH3:3711
CH4:2578
CH2:1434
CH3:3709
CH4:2579
CH2:1434
CH3:3707
CH4:2577
CH2:1431
CH3:3702
CH4:2579
CH2:1436
CH3:3702
CH4:2577
CH2:1437
CH3:3702
CH4:2578
CH2:1436
CH3:3700
CH4:2578
CH2:1449
CH3:3696
CH4:2422
CH2:1470
CH3:1018
CH4:2392
CH2:1518
CH3:839
CH4:2390
CH2:1506
CH3:815
CH4:2407
CH2:1491
CH3:809
CH4:2389
CH2:1490
CH3:806
CH4:2390
CH2:1507
CH3:802
CH4:2389
CH2:1508
CH3:800
CH4:2390
CH2:1503
CH3:803
CH4:2389
CH2:1489
CH3:801
CH4:2418
CH2:1494
CH3:3695
CH4:2581
CH2:1432
CH3:3743
CH4:2580
CH2:1439
CH3:3735
CH4:2579
CH2:1445
CH3:3726
CH4:2579
CH2:1439
CH3:3717
CH4:2579
CH2:1424
CH3:3716
CH4:2578
CH2:1415
CH3:3712
CH4:2578
CH2:1415
CH3:3706
CH4:2597
CH2:1426
CH3:3705
CH4:2598
CH2:1423
CH3:3703
CH4:2578
CH2:1409
CH3:3705
CH4:2577
CH2:1417
CH3:3708
CH4:2579
CH2:1416
CH3:3709
CH4:2396
CH2:1426
CH3:884
CH4:2390
CH2:1403
CH3:821
CH4:2390
CH2:1487
CH3:806
CH4:2390
CH2:1460
CH3:800
CH4:2390
CH2:1438
CH3:800
CH4:2388
CH2:1399
CH3:799
CH4:2388
CH2:1391
CH3:795
CH4:2389
CH2:1246
CH3:794
CH4:2389
CH2:1234
CH3:796
CH4:2389
CH2:1214
CH3:795
CH4:2388
CH2:1196
CH3:795
CH4:2390
CH2:1175
CH3:795
CH4:2390
CH2:1185
CH3:797
CH4:2389
CH2:1222
CH3:798
CH4:2401
CH2:1408
CH3:798
CH4:2390
CH2:1613
CH3:797
CH4:2390
CH2:1589
CH3:795
CH4:2388
CH2:1570
CH3:796
CH4:2388
CH2:1543
CH3:797
CH4:2388
CH2:1528
CH3:797
CH4:2390
CH2:1511
CH3:798
CH4:2389
CH2:1511
CH3:798
CH4:2389
CH2:1511
CH3:800
CH4:2389
CH2:1530
CH3:803
CH4:2390
CH2:1547
CH3:804
CH4:2390
CH2:1565
CH3:807
CH4:2390
CH2:1574
CH3:809
CH4:2389
CH2:1576
CH3:810
CH4:2390
CH2:1580
CH3:809
CH4:2389
CH2:1577
CH3:808
CH4:2390
CH2:1573
CH3:807
CH4:2390
CH2:1569
CH3:805
CH4:2406
CH2:1570
CH3:804
CH4:2408
CH2:1568
CH3:800
CH4:2390
CH2:1547
CH3:799
CH4:2390
CH2:1544
CH3:800
CH4:2390
CH2:1530
CH3:803
CH4:2389
CH2:1520
CH3:806
CH4:2390
CH2:1534
CH3:805

    0027.adc12_sequence_conversion_LP_MSPM0L1306_nortos_ticlang.zip
    When I increase CH3, CH4 should not increase. Seems to me that there is a crosstalk between channels.

    CH2=PIR input. Op amp output.
    CH3= CDS input (light sensor) 5k divider with a CDS pull up.
    CH4=Resistor divider to measure voltage. R-top=1Meg. R-bot=200k. (1/6 divider).

    Hope it will help you to understand.

  • 0 in reply to Sebastien Grenier
    Prodigy 100 points

    Hi Eason, I moved the CDS from CH4 (PA22) to CH7 (PA18) and it's working now for the CH4 reading.
    Seems like there is a crosstalk between CH4 & CH3.
    I still have a problem on CH7 (CDS) It varies (not stable) for no reason...??? When I probe the CH7, I get this weird behavior. Let me know if I did something wrong.


  • 0 in reply to Sebastien Grenier
    Prodigy 100 points

    Hi Eason, I transfered the project on the LP-MSPM0C1104 I have also. The analog pins are configured like in this picture. Now the problem is not present in the C1104 EVB. Do you know what could had been wrong on the L1306 before?

  • 0 in reply to Sebastien Grenier
    TI__Mastermind 40195 points

    Can you give a description for the wave? Is it the wave when ADC doing the sampling?

    Does the test on LP?  PA18 is connected to a pulled down resistor.

    Can you change the CDS to CH3 and double check the wave again? This can help check whether the problem lies on the channel 7.

  • +1 in reply to Eason Zhou
    Prodigy 100 points

    Hi Eason, the waveforme is the ADC pin. It should be stable. I tried on PA24 (CH3) this morning. I do not see the waveform but I see a leakage between CH3 & PA22 (CH4). I found the problem. The Jumpers where in place on PA24 and PA22. My fault. Pardon me.