请问如何切换 PWM Mode

VIM3 上的 PWM 工作模式是 IN,想切成 ALT3,有什么方法吗?

我有两台机,一台是 Ubuntu 20.04,PWM 是 ALT3;另外一台是 Ubuntu 20.04.02,PWM 是 IN。好烦恼。

@gzbigegg 你用的什么固件?两台一样的?

还是补一个回复,有可能帮助到同样会踩坑的朋友。

用在官网上直接下载的固件,Ubuntu 20.04,PWM(GPIO 35)的工作模式是 ALT3;
在上面这个固件基础上,不小心 apt-get update && apt-get upgrade,系统变成了 Ubuntu 20.04.02,PWM 的工作模式就是 IN 了。

升级要小心。

你下的哪个版本?我这边测试没发现问题

khadas@Khadas:~$ cat /etc/fenix-release 
# PLEASE DO NOT EDIT THIS FILE
BOARD=VIM3
VENDOR=Amlogic
VERSION=1.0.5
ARCH=arm64
INITRD_ARCH=arm64
INSTALL_TYPE=EMMC
IMAGE_VERSION=V1.0.5-210430
################ GIT VERSION ################
UBOOT_GIT_VERSION=khadas-vims-v1.0.5-release
LINUX_GIT_VERSION=khadas-vims-v1.0.5-release
FENIX_GIT_VERSION=v1.0.5
#############################################
khadas@Khadas:~$ 
khadas@Khadas:~$ 
khadas@Khadas:~$ 
khadas@Khadas:~$ gpio  readall
 +------+-----+----------+------+---+----+---- Model  Khadas VIM3 --+----+---+------+----------+-----+------+
 | GPIO | wPi |   Name   | Mode | V | DS | PU/PD | Physical | PU/PD | DS | V | Mode |   Name   | wPi | GPIO |
 +------+-----+----------+------+---+----+-------+----++----+-------+----+---+------+----------+-----+------+
 |      |     |       5V |      |   |    |       |  1 || 21 |       |    |   |      | GND      |     |      |
 |      |     |       5V |      |   |    |       |  2 || 22 | P/U   |    | 1 | ALT1 | PIN.A15  | 6   |  475 |
 |      |     |   USB_DM |      |   |    |       |  3 || 23 | P/U   |    | 1 | ALT1 | PIN.A14  | 7   |  474 |
 |      |     |   USB_DP |      |   |    |       |  4 || 24 |       |    |   |      | GND      |     |      |
 |      |     |      GND |      |   |    |       |  5 || 25 | P/U   |    | 1 | ALT0 | PIN.AO2  | 8   |  498 |
 |      |     |   MCU3V3 |      |   |    |       |  6 || 26 | P/U   |    | 1 | ALT0 | PIN.AO3  | 9   |  499 |
 |      |     |  MCUNRST |      |   |    |       |  7 || 27 |       |    |   |      | 3V3      |     |      |
 |      |     |  MCUSWIM |      |   |    |       |  8 || 28 |       |    |   |      | GND      |     |      |
 |      |     |      GND |      |   |    |       |  9 || 29 | P/D   |    | 0 | ALT0 | PIN.A1   | 10  |  461 |
 |      |  18 |     ADC0 |      |   |    |       | 10 || 30 | P/D   |    | 1 | ALT0 | PIN.A0   | 11  |  460 |
 |      |     |      1V8 |      |   |    |       | 11 || 31 | P/D   |    | 0 | ALT0 | PIN.A3   | 12  |  463 |
 |      |  19 |     ADC1 |      |   |    |       | 12 || 32 | P/D   |    | 0 | ALT0 | PIN.A2   | 13  |  462 |
 |  506 |   1 | PIN.AO10 | ALT3 | 0 |    |   P/U | 13 || 33 | P/D   |    | 0 | ALT1 | PIN.A4   | 14  |  464 |
 |      |     |     GND3 |      |   |    |       | 14 || 34 |       |    |   |      | GND      |     |      |
 |  433 |   2 |   PIN.H6 | ALT1 | 0 |    |   P/D | 15 || 35 | P/D   |    | 0 | ALT3 | PWM-F    | 15  |  432 |
 |  434 |   3 |   PIN.H7 | ALT1 | 1 |    |   P/D | 16 || 36 |       |    |   |      | RTC      |     |      |
 |      |     |      GND |      |   |    |       | 17 || 37 | P/D   |    | 0 | IN   | PIN.H4   | 16  |  431 |
 |  497 |   4 |  PIN.AO1 | ALT0 | 1 |    |   P/U | 18 || 38 |       |    |   |      | MCU-FA1  |     |      |
 |  496 |   5 |  PIN.AO0 | ALT0 | 1 |    |   P/U | 19 || 39 | P/D   |    | 0 | IN   | PIN.Z15  | 17  |  426 |
 |      |     |      3V3 |      |   |    |       | 20 || 40 |       |    |   |      | GND      |     |      |
 +------+-----+----------+------+---+----+-------+----++----+-------+----+---+------+----------+-----+------+

同时你可以提供下这个文件看看:cat /boot/env.txt

我下了你们官网的固件是没问题的,手贱升级了之后(apt-get update && apt-get upgrade),就不行了。没事,这个问题不大了。