Diagnosing stepper timing issues with another esp32
Unfortunately I have been running into issues with the stepper not rotating deterministically. Sometimes it will vibrate, sometimes it will spin clockwise, sometimes counterclockwise. This issue is related to synchronizing channels, which has been reported as a github issue
In order to approach this issue systematically I will use a logic analyzer. Since lead times are significant due to a current pandemic I will be utilizing another esp32 to capture data.
Logic Analysis?
Digital signals are a series of high/low values over time. The stepper driver requires synchronizing 4 digital channels over time in order to provide smooth movement. By capturing samples many times per second the precise times between high/low can be measured and compared.
Esp32 Sigrok
The github user Ebiroll has published the esp32_sigrok repo, which claims to be a sump compatible device which can interface with the sigrok software suite.
Installing pulseview on Nixos
Adding pulseview to shell.nix started with a core dump due to
$ pulseview
Fatal Python error: initfsencoding: Unable to get the locale encoding
ModuleNotFoundError: No module named 'encodings'
Current thread 0x00007fc63e821000 (most recent call first):
[1] 24318 abort (core dumped) pulseviewShell.nix includes setting PYTHONHOME, turns out that wasn't needed and by removing that value pulseview ran just fine
Setup
My initial desire is to set this device up to use USB rather than the default WIFI to capture, since this computer does not have a wireless card. I have edited app-config.h to resemble
`
/// CHANGE CONFIGURATION HERE!!
#undef CONFIG_EXAMPLE_USE_TFT
#undef SUMP_OVER_UART
#define SUMP_OVER_UART 1
//#define SCPI_ON_NETWORK 1
//#define SUMP_ON_NETWORK 1
#undef DEBUG_SUMP
//#define DEBUG_LOG_ENABLE 1
//#define OTA_RUN_SERVER 1
#define UART_TEST_OUTPUT 1
#define UART_OUTPUT_PIN 18
#define UART_RX_PIN 19
#define PULSE_PIN 17
#define RMT_PULSES 1
//#undef RMT_PULSES
#define RUN_IN_QEMU 0Building
Using the previously configured environment I ran
$ idf.py build
...
cc1: some warnings being treated as errors
...
../main/ota_server.c:35:42: warning: passing argument 1 of 'ip4addr_ntoa' from incompatible pointer type [-Wincompatible-pointer-types]To fix this I added the following to my shell setup:
export CFLAGS_COMPILE="-Wno-error=incompatible-pointer-types -Wno-error=implicit-function-declaration"Unfortunately two errors still stuck out:
../main/analog-testdata.c:250:13: error: implicit declaration of function 'i2s_write_bytes'; did you mean 'i2s_write_expand'? [-Werror=implicit-function-declaration]
...
../main/analog.c:187:5: error: implicit declaration of function 'esp_adc_cal_get_characteristics'; did you mean 'esp_adc_cal_characterize'? [-Werror=implicit-function-declaration]I am using the v4.2 prerelease and according to some cursory searching esp_adc_cal_get_characteristics and i2s_write_bytes are deprecated.
- esp_adc_cal_get_characteristics(V_REF, ADC_ATTEN_DB_0, ADC_WIDTH_BIT_12, &characteristics);
-
+ esp_adc_cal_characterize(ADC_UNIT_1, ADC_ATTEN_DB_0, ADC_WIDTH_BIT_12, V_REF, &characteristics);
+ size_t bytes_written;
- i2s_write_bytes(EXAMPLE_I2S_NUM, (const char*) i2s_write_buff, i2s_wr_len, portMAX_DELAY);
+ i2s_write(EXAMPLE_I2S_NUM, (const char*) i2s_write_buff, i2s_wr_len, &bytes_written, portMAX_DELAY);Without understanding exactly what is changing these look functionally similar and allows it to build
Locating
After building and executing sigrok-cli was run to scan for devices:
$ sigrok-cli -d ols:conn=/dev/ttyUSB0 -l 5 --scan
sr: [00:00.000000] log: libsigrok loglevel set to 5.
sr: [00:00.000016] backend: libsigrok 0.5.1/5:0:1 (rt: 0.5.1/5:0:1).
sr: [00:00.000036] backend: Libs: glib 2.62.5 (rt: 2.62.5/6205:5), libzip 1.6.0, libserialport 0.1.1/1:0:1 (rt: 0.1.1/1:0:1), libusb-1.0 1.0.23.11397 API 0x01000107, libftdi 1.4, librevisa 0.0.20130412.
sr: [00:00.000055] backend: Host: x86_64-pc-linux-gnu, little-endian.
sr: [00:00.000063] backend: SCPI backends: TCP, RPC, serial, VISA, USBTMC.
sr: [00:00.000067] backend: Firmware search paths:
sr: [00:00.000082] backend: - /home/username/.local/share/sigrok-firmware
sr: [00:00.000088] backend: - /nix/store/xbwknpb4165jvhw6sm8da3hnrg01jgb2-libsigrok-0.5.1/share/sigrok-firmware
sr: [00:00.000094] backend: - /home/username/.nix-profile/share/sigrok-firmware
sr: [00:00.000101] backend: - /etc/profiles/per-user/username/share/sigrok-firmware
sr: [00:00.000105] backend: - /nix/var/nix/profiles/default/share/sigrok-firmware
sr: [00:00.000112] backend: - /run/current-system/sw/share/sigrok-firmware
sr: [00:00.000130] backend: Sanity-checking all drivers.
sr: [00:00.000138] backend: Sanity-checking all input modules.
sr: [00:00.000143] backend: Sanity-checking all output modules.
sr: [00:00.000152] backend: Sanity-checking all transform modules.
srd: libsigrokdecode loglevel set to 5.
sr: [00:00.007146] hwdriver: sr_config_list(): key 2147418112 (NULL) sdi (nil) cg NULL -> [uint32 20000, 20001]
sr: [00:00.007156] openbench-logic-sniffer: Probing /dev/ttyUSB0.
sr: [00:00.007163] serial: Opening serial port '/dev/ttyUSB0' (flags 1).
sr: [00:00.007717] serial: Parsing parameters from "115200/8n1".
sr: [00:00.007757] serial: Setting serial parameters on port /dev/ttyUSB0.
sr: [00:00.007770] openbench-logic-sniffer: Sending cmd 0x00.
sr: [00:00.007784] serial: Wrote 1/1 bytes.
sr: [00:00.007788] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.007818] openbench-logic-sniffer: Sending cmd 0x00.
sr: [00:00.007838] serial: Wrote 1/1 bytes.
sr: [00:00.007843] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.007878] openbench-logic-sniffer: Sending cmd 0x00.
sr: [00:00.007889] serial: Wrote 1/1 bytes.
sr: [00:00.007893] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.007917] openbench-logic-sniffer: Sending cmd 0x00.
sr: [00:00.007927] serial: Wrote 1/1 bytes.
sr: [00:00.007929] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.007957] openbench-logic-sniffer: Sending cmd 0x00.
sr: [00:00.007967] serial: Wrote 1/1 bytes.
sr: [00:00.007972] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.008082] openbench-logic-sniffer: Sending cmd 0x02.
sr: [00:00.008092] serial: Wrote 1/1 bytes.
sr: [00:00.008097] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.018216] serial: Read 4/4 bytes.
sr: [00:00.018227] openbench-logic-sniffer: Sending cmd 0x04.
sr: [00:00.018240] serial: Wrote 1/1 bytes.
sr: [00:00.018246] serial: Draining serial port /dev/ttyUSB0.
sr: [00:00.028358] serial: Read 1/1 bytes.
sr: [00:00.028383] serial: Read 1/1 bytes.
sr: [00:00.028389] serial: Read 1/1 bytes.
sr: [00:00.028395] serial: Read 1/1 bytes.
sr: [00:00.028403] serial: Read 1/1 bytes.
sr: [00:00.028411] serial: Read 1/1 bytes.
sr: [00:00.028422] serial: Read 1/1 bytes.
sr: [00:00.028425] openbench-logic-sniffer: Got metadata key 0x01 value 'ESP32'.
sr: [00:00.028438] serial: Read 1/1 bytes.
sr: [00:00.028451] serial: Read 4/4 bytes.
sr: [00:00.028455] openbench-logic-sniffer: Got metadata key 0x20 value 0x00000008.
sr: [00:00.028470] serial: Read 1/1 bytes.
sr: [00:00.028480] serial: Read 4/4 bytes.
sr: [00:00.028484] openbench-logic-sniffer: Got metadata key 0x21 value 0x00002000.
sr: [00:00.028495] serial: Read 1/1 bytes.
sr: [00:00.028505] serial: Read 4/4 bytes.
sr: [00:00.028509] openbench-logic-sniffer: Got metadata key 0x23 value 0x00002710.
sr: [00:00.028519] serial: Read 1/1 bytes.
sr: [00:00.028530] serial: Read 1/1 bytes.
sr: [00:00.028534] openbench-logic-sniffer: Got metadata key 0x41 value 0x02.
sr: [00:00.028543] serial: Read 1/1 bytes.
sr: [00:00.028546] openbench-logic-sniffer: Got metadata key 0x00, metadata ends.
sr: [00:00.028549] openbench-logic-sniffer: Failed to set default samplerate (200000).
sr: [00:00.028555] serial: Closing serial port /dev/ttyUSB0.
sr: [00:00.028768] hwdriver: Scan found 1 devices (ols).
The following devices were found:
ols - ESP32 with 8 channels: 0 1 2 3 4 5 6 7
sr: [00:00.028796] hwdriver: Cleaning up all drivers.
sr: [00:00.028802] serial: Cannot close unopened serial port /dev/ttyUSB0.Looks good to me!
Connecting
Let's try it out by selecting the connection dropdown and choosing the options
Choose the driver: Openbench Logic Sniffer (ols) Choose the interface: Serial Port /dev/ttyUSB0 Scan for devices Select the device: ESP32 with 8 channels
Uh...
So it turns out I have one esp32 and one esp8266, and cannot logic analyze a device with itself. Time to use an alternative device!