改变gpadc采样率：

cd /sys/class/gpadc/
echo 5000 > sr #设置gpadc采样率为10000，gpadc采样率范围为400~100000；
cat sr #查看gpadc当前采样率。

然后通过万用表测量GPADC0引脚的电压，

发现电压也会随adc采样率的改变而改变。

这正常吗？

请问你这个是怎么配置gpadc的 就是作为采集电压的 我目前好像就是采集的都是一样的

@jr_online
仔细检查了一下设备树，发现 gpadc 没打开。
现在打开之后重新编译就能使用了。
感谢！

好的

@jr_online
请问一下修改那些地方能使用这个普通的 gpadc 呀？
我看它设备树里面都是配置的adc按键，不能直接去读取相关的adc值。
使用普通adc 命令就会报错。

/sys/class/gpadc# echo 5000 > sr 
[ 1536.126834] 8<--- cut here ---
[ 1536.130277] Unable to handle kernel NULL pointer dereference at virtual address 00000084
[ 1536.139439] pgd = b0db3a19
[ 1536.142531] [00000084] *pgd=00000000
[ 1536.146601] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[ 1536.152563] Modules linked in: sx1262(O) sunxi_ce [last unloaded: sx1262]
[ 1536.160192] CPU: 0 PID: 1687 Comm: bash Tainted: G           O      5.4.61 #2
[ 1536.168197] Hardware name: Generic DT based system
[ 1536.173578] PC is at sr_store+0x9c/0x100
[ 1536.177978] LR is at _kstrtoull+0x34/0x8c
[ 1536.182473] pc : [<c0507f60>]    lr : [<c035800c>]    psr: a0000013
[ 1536.189500] sp : c4569e98  ip : c0507ec4  fp : 00000000
[ 1536.195360] r10: 00000004  r9 : 00000051  r8 : c5108710
[ 1536.201221] r7 : c4569f70  r6 : 00000000  r5 : 00000005  r4 : c0c03dc8
[ 1536.208542] r3 : 00000000  r2 : 00001388  r1 : 016e3600  r0 : 00000000
[ 1536.215865] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[ 1536.223871] Control: 10c5387d  Table: 445e006a  DAC: 00000051
[ 1536.230321] Process bash (pid: 1687, stack limit = 0x0c6dc0e4)
[ 1536.236864] Stack: (0xc4569e98 to 0xc456a000)

那你的设备树是怎么配置的呢？可以贴出来看看和我的有啥不一样。
我也看不懂你的报错，我就是在命令行去操作gpadc的。

/sys/class/gpadc# echo 5000 > sr 
[ 1536.126834] 8<--- cut here ---
[ 1536.130277] Unable to handle kernel NULL pointer dereference at virtual address 00000084
[ 1536.139439] pgd = b0db3a19
[ 1536.142531] [00000084] *pgd=00000000
[ 1536.146601] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
[ 1536.152563] Modules linked in: sx1262(O) sunxi_ce [last unloaded: sx1262]
[ 1536.160192] CPU: 0 PID: 1687 Comm: bash Tainted: G           O      5.4.61 #2
[ 1536.168197] Hardware name: Generic DT based system
[ 1536.173578] PC is at sr_store+0x9c/0x100
[ 1536.177978] LR is at _kstrtoull+0x34/0x8c
[ 1536.182473] pc : [<c0507f60>]    lr : [<c035800c>]    psr: a0000013
[ 1536.189500] sp : c4569e98  ip : c0507ec4  fp : 00000000
[ 1536.195360] r10: 00000004  r9 : 00000051  r8 : c5108710
[ 1536.201221] r7 : c4569f70  r6 : 00000000  r5 : 00000005  r4 : c0c03dc8
[ 1536.208542] r3 : 00000000  r2 : 00001388  r1 : 016e3600  r0 : 00000000
[ 1536.215865] Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
[ 1536.223871] Control: 10c5387d  Table: 445e006a  DAC: 00000051
[ 1536.230321] Process bash (pid: 1687, stack limit = 0x0c6dc0e4)
[ 1536.236864] Stack: (0xc4569e98 to 0xc456a000)

@jr_online 正常的

这电压不就不准了吗？不懂