Re: [beagleboard] I2C on PRU: how to?

[Pedro Henrique Fonseca Bertoleti]

Mark, thanks!

Em qui, 21 de jan de 2021 00:38, 'Mark Lazarewicz' via BeagleBoard <
beagleboard@googlegroups.com> escreveu:

> Hello Pedro
>
> Is their a block diagram that shows the Interconnect peripherals in TRM?
> That used to be pretty standard in TRM and answers #1
>
> I avoid Linux so I can't answer #2 but I'm pretty sure this question was
> asked before in this group.
>
> Lastly refine your Google arguments I did find this but it may be for bare
> bones system.
>
>
>
> https://e2e.ti.com/support/processors/f/791/t/458311?AM335x-PRU-access-to-I2C-and-other-peripherals-on-L4-PER-bus
>
>
> I would start with the block diagram for L4
>
> Lastly Mark Yoder a professor who teaches embedded Linux has various
> tutorial and cookbooks. He's very gifted and his documents are clearly
> written and updated. Dig around their last after understanding what's
> possible would be my approach.
>
> You know what they say about about too many cooks in the Kitchen Pedro?
>
> They spoil the soup 🤔🤗
>
> If you do some research and then narrow down the specifics you won't be
> misled
>
> Hopefully I've offered something positive to help you.
>
> Mark
>
>
>
>
> Sent from Yahoo Mail on Android
> 
>
> On Wed, Jan 20, 2021 at 8:10 PM, Pedro Henrique Fonseca Bertoleti
>  wrote:
> Hi everyone. My name is Pedro Bertoleti and I'm from Brazil.
>
> I'm learning about the PRUs on BeagleBone (I'm using BeagleBone Black
> board) and I wanna read IMU and another I2C sensors in PRU firmware (to be
> able to implement some motion algorithms and stuffs like that in PRU
> firmware, due to its real-time scope).
>
> However, I'm not sure on how to use I2C in PRU. Per my understanding:
>
> A) PRUs have no hardware dedicated to I2C (nor SPI)
> B) I've seen some SPI examples with PRU on Internet, however in all of
> them SPI communication was made using bit-bang technique.
>
> So, would you help me answering the following questions?
>
> 1) Do I need bit-banging to communicate PRU to I2C devices? I mean, isn't
> there another way to use I2C in PRU?
> 2) If answer above is yes, is there an way to change gpio direction (input
> to outut and vice versa) inside PRU firmware? I ask this because, as I read
> so far, only config-pin (Linux side) can "enable" a gpio to PRU and set its
> direction, and glio direction change will be needed if I need to make I2C
> using bit-bang technique.
>
> Please, would anyone shed some light on it?
>
>
>
> Thanks in advance.
>
> --
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> 
> .
>
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> 
> .
>

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Re: [beagleboard] I2C on PRU: how to?

['Mark Lazarewicz' via BeagleBoard]

Pedro greetings.
Np The discussion in this group about #2 should be helpful as I remember there 
were conflicting answers about pin mixing after Linux is running. I'll see if I 
can find the post later it may have been another pin or not  i2c but concept 
was there. try and Google beagleboard group PRU I2C pin mux.You still have 
issue if Linux is using this pin but not insurmountable Let us know how you are 
doing I'll do some digging later to
Cheers
Sent from Yahoo Mail on Android 
 
  On Thu, Jan 21, 2021 at 8:54 AM, Pedro Henrique Fonseca 
Bertoleti wrote:   Mark, thanks!
Em qui, 21 de jan de 2021 00:38, 'Mark Lazarewicz' via BeagleBoard 
 escreveu:

Hello Pedro
Is their a block diagram that shows the Interconnect peripherals in TRM? That 
used to be pretty standard in TRM and answers #1
I avoid Linux so I can't answer #2 but I'm pretty sure this question was asked 
before in this group.
Lastly refine your Google arguments I did find this but it may be for bare 
bones system.
have 
https://e2e.ti.com/support/processors/f/791/t/458311?AM335x-PRU-access-to-I2C-and-other-peripherals-on-L4-PER-bus


I would start with the block diagram for L4 
Lastly Mark Yoder a professor who teaches embedded Linux has various tutorial 
and cookbooks. He's very gifted and his documents are clearly written and 
updated. Dig around their last after understanding what's possible would be my 
approach.
You know what they say about about too many cooks in the Kitchen Pedro? 
They spoil the soup 🤔🤗 
If you do some research and then narrow down the specifics you won't be misled
Hopefully I've offered something positive to help you.
Mark



Sent from Yahoo Mail on Android 
 
  On Wed, Jan 20, 2021 at 8:10 PM, Pedro Henrique Fonseca 
Bertoleti wrote:   Hi everyone. My name is Pedro 
Bertoleti and I'm from Brazil.
I'm learning about the PRUs on BeagleBone (I'm using BeagleBone Black board) 
and I wanna read IMU and another I2C sensors in PRU firmware (to be able to 
implement some motion algorithms and stuffs like that in PRU firmware, due to 
its real-time scope).
However, I'm not sure on how to use I2C in PRU. Per my understanding:
A) PRUs have no hardware dedicated to I2C (nor SPI)B) I've seen some SPI 
examples with PRU on Internet, however in all of them SPI communication was 
made using bit-bang technique.
So, would you help me answering the following questions?
1) Do I need bit-banging to communicate PRU to I2C devices? I mean, isn't there 
another way to use I2C in PRU?2) If answer above is yes, is there an way to 
change gpio direction (input to outut and vice versa) inside PRU firmware? I 
ask this because, as I read so far, only config-pin (Linux side) can "enable" a 
gpio to PRU and set its direction, and glio direction change will be needed if 
I need to make I2C using bit-bang technique.
Please, would anyone shed some light on it?


Thanks in advance.

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[beagleboard] Help to mate a GUI

[ciriaco ortiz carrasco]

someone knows how to make a little GUI using beaglebone black

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Re: [beagleboard] Help to mate a GUI

[jonnymo]

Could you be a bit more specific with what you are looking for?
Will this be with a display or headless?

With Display, something like PyGame, Qt, Gtk, Tkinter, wxPython and many
others.

Headless, something like Flask or Bonescript(NodeJS) would allow you to get
a webserver based gui using a python or javascript backend.

Jon

On Thu, Jan 21, 2021 at 10:39 AM ciriaco ortiz carrasco 
wrote:

> someone knows how to make a little GUI using beaglebone black
>
> --
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> 
> .
>

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Re: [beagleboard] I2C on PRU: how to?

['Mark Lazarewicz' via BeagleBoard]

 Hello Pedro 
The thread I found turned into a big argument it looks like thats why I 
remembered it and made a reference to too many cooks giving advice. I will 
provide link but I am having trouble finding entire thread in the mail archive
[beagleboard] Re: Problems Reconfiguring GPIO's


| 
| 
| 
|  |  |

 |

 |
| 
|  | 
[beagleboard] Re: Problems Reconfiguring GPIO's


 |

 |

 |

As you see some members active in group were postulating and I don;t want to 
start trouble I wanted to help but I was afraid the couldd result in bad advise.
Start with Part 1 and convince yourself its possible by finding some PRU code 
for I2C that pretty much means its possible at least you will learn about PRUs 
start simple. Feel free to start another thread but check github and Marks PRU 
stuff Ill be watching for updates I would like to be more helpful. 
Did you find  the L3 Per block diagram ?
Best wishes my friend keep plugging!
Mark
On Thursday, January 21, 2021, 08:54:22 AM CST, Pedro Henrique Fonseca 
Bertoleti  wrote:  
 
 Mark, thanks!
Em qui, 21 de jan de 2021 00:38, 'Mark Lazarewicz' via BeagleBoard 
 escreveu:

Hello Pedro
Is their a block diagram that shows the Interconnect peripherals in TRM? That 
used to be pretty standard in TRM and answers #1
I avoid Linux so I can't answer #2 but I'm pretty sure this question was asked 
before in this group.
Lastly refine your Google arguments I did find this but it may be for bare 
bones system.

https://e2e.ti.com/support/processors/f/791/t/458311?AM335x-PRU-access-to-I2C-and-other-peripherals-on-L4-PER-bus


I would start with the block diagram for L4 
Lastly Mark Yoder a professor who teaches embedded Linux has various tutorial 
and cookbooks. He's very gifted and his documents are clearly written and 
updated. Dig around their last after understanding what's possible would be my 
approach.
You know what they say about about too many cooks in the Kitchen Pedro? 
They spoil the soup 🤔🤗 
If you do some research and then narrow down the specifics you won't be misled
Hopefully I've offered something positive to help you.
Mark



Sent from Yahoo Mail on Android 
 
  On Wed, Jan 20, 2021 at 8:10 PM, Pedro Henrique Fonseca 
Bertoleti wrote:   Hi everyone. My name is Pedro 
Bertoleti and I'm from Brazil.
I'm learning about the PRUs on BeagleBone (I'm using BeagleBone Black board) 
and I wanna read IMU and another I2C sensors in PRU firmware (to be able to 
implement some motion algorithms and stuffs like that in PRU firmware, due to 
its real-time scope).
However, I'm not sure on how to use I2C in PRU. Per my understanding:
A) PRUs have no hardware dedicated to I2C (nor SPI)B) I've seen some SPI 
examples with PRU on Internet, however in all of them SPI communication was 
made using bit-bang technique.
So, would you help me answering the following questions?
1) Do I need bit-banging to communicate PRU to I2C devices? I mean, isn't there 
another way to use I2C in PRU?2) If answer above is yes, is there an way to 
change gpio direction (input to outut and vice versa) inside PRU firmware? I 
ask this because, as I read so far, only config-pin (Linux side) can "enable" a 
gpio to PRU and set its direction, and glio direction change will be needed if 
I need to make I2C using bit-bang technique.
Please, would anyone shed some light on it?


Thanks in advance.

-- 
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Re: [beagleboard] I2C on PRU: how to?

[Pedro Henrique Fonseca Bertoleti]

Hi Mark.

First of all, thank you for all the information. I've learnt a lot.
After making some reads about PRU in AM335x TRM,  I've confirmed PRU can
access various SIP peripherals, including the I2C interfaces (thank god!
Bit-banging an I2C would be boring as hell).

Per my understanding (and accordingly to pru cook book), I2C2 (for example)
is mapped into 0x4819C000 memory address. Also, configuration registers
must be set in another registers to make I2C2 work properly (I'm trying to
understand them now).

Please, correct me if I'm wrong:
If I write/read data from 0x4819C000, I'll be able to communicate via I2C2
inside PRU, right?

Also: once I2C2 is up and running in Linux side (= it has been configured
at some time during bootloader initialization), is it enough for me to yse
I2C2 in PRU by just writting and reading the address 0x4819C000?

Sorry if I understood it wrong.


Best Regards,
Pedro Bertoleti

Em qui, 21 de jan de 2021 20:27, 'Mark Lazarewicz' via BeagleBoard <
beagleboard@googlegroups.com> escreveu:

> Hello Pedro
>
> The thread I found turned into a big argument it looks like thats why I
> remembered it and made a reference to too many cooks giving advice. I will
> provide link but I am having trouble finding entire thread in the mail
> archive
>
> [beagleboard] Re: Problems Reconfiguring GPIO's
> 
>
> [beagleboard] Re: Problems Reconfiguring GPIO's
>
> 
> As you see some members active in group were postulating and I don;t want
> to start trouble I wanted to help but I was afraid the couldd result in bad
> advise.
>
> Start with Part 1 and convince yourself its possible by finding some PRU
> code for I2C that pretty much means its possible at least you will learn
> about PRUs start simple. Feel free to start another thread but check github
> and Marks PRU stuff Ill be watching for updates I would like to be more
> helpful.
>
> Did you find  the L3 Per block diagram ?
>
> Best wishes my friend keep plugging!
>
> Mark
>
> On Thursday, January 21, 2021, 08:54:22 AM CST, Pedro Henrique Fonseca
> Bertoleti  wrote:
>
>
> Mark, thanks!
>
> Em qui, 21 de jan de 2021 00:38, 'Mark Lazarewicz' via BeagleBoard <
> beagleboard@googlegroups.com> escreveu:
>
> Hello Pedro
>
> Is their a block diagram that shows the Interconnect peripherals in TRM?
> That used to be pretty standard in TRM and answers #1
>
> I avoid Linux so I can't answer #2 but I'm pretty sure this question was
> asked before in this group.
>
> Lastly refine your Google arguments I did find this but it may be for bare
> bones system.
>
>
>
> https://e2e.ti.com/support/processors/f/791/t/458311?AM335x-PRU-access-to-I2C-and-other-peripherals-on-L4-PER-bus
>
>
> I would start with the block diagram for L4
>
> Lastly Mark Yoder a professor who teaches embedded Linux has various
> tutorial and cookbooks. He's very gifted and his documents are clearly
> written and updated. Dig around their last after understanding what's
> possible would be my approach.
>
> You know what they say about about too many cooks in the Kitchen Pedro?
>
> They spoil the soup 🤔🤗
>
> If you do some research and then narrow down the specifics you won't be
> misled
>
> Hopefully I've offered something positive to help you.
>
> Mark
>
>
>
>
> Sent from Yahoo Mail on Android
> 
>
> On Wed, Jan 20, 2021 at 8:10 PM, Pedro Henrique Fonseca Bertoleti
>  wrote:
> Hi everyone. My name is Pedro Bertoleti and I'm from Brazil.
>
> I'm learning about the PRUs on BeagleBone (I'm using BeagleBone Black
> board) and I wanna read IMU and another I2C sensors in PRU firmware (to be
> able to implement some motion algorithms and stuffs like that in PRU
> firmware, due to its real-time scope).
>
> However, I'm not sure on how to use I2C in PRU. Per my understanding:
>
> A) PRUs have no hardware dedicated to I2C (nor SPI)
> B) I've seen some SPI examples with PRU on Internet, however in all of
> them SPI communication was made using bit-bang technique.
>
> So, would you help me answering the following questions?
>
> 1) Do I need bit-banging to communicate PRU to I2C devices? I mean, isn't
> there another way to use I2C in PRU?
> 2) If answer above is yes, is there an way to change gpio direction (input
> to outut and vice versa) inside PRU firmware? I ask this because, as I read
> so far, only config-pin (Linux side) can "enable" a gpio to PRU and set its
> direction, and glio direction change will be needed if I need to make I2C
> using bit-bang technique.
>
> Please, would anyone shed some light on it?
>
>
>
> Thanks in advance.
>
> --
> For more options, visit http://beagleboard.org/discuss
> ---
> You received this message because you are subscribed to the Google Group

[beagleboard] New BeagleV GoogleGroup

[Jason Kridner]

Based on (albeit somewhat limited, but pointed) feedback, I have taken up 
the suggestion of moving BeagleV discussion to another Google Group.

https://groups.google.com/g/beaglev

While I have some concerns it will hurt building critical mass of that 
discussion, it will certainly reduce noise for those only interested in the 
TI/ARM-based boards. Hope this works for you!

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Re: [beagleboard] I2C on PRU: how to?

['Mark Lazarewicz' via BeagleBoard]

Hello Pedro
I'd have to check exact addresses but you have the correct idea. If you use 
Linux to set muxing so pins are  I2C this eliminates investigation of that's 
even possible from PRU just have Linux do it.
This then leaves 
Also, configuration registers must be set in another registers to make I2C2 
work properly 

Then you read and write to a register as you said to transmit or receive
The config register's usually allow polled or interrupt to be generated. 
Polling is probably easier 
The PRU examples may have both I haven't looked at the code.
The important part is understanding exact adresses of all registers and which 
bits are being polled or checked.
You look at the code and header files and calculate what addresses are being 
Access. Look in TRM see address code using and say ok he's polling for data on 
bit 5 or oh here he's transmitting a byte.
Of course you need a device wired up to communicate.
Probably the simplest test is to read a status register from the slave device 
that contains known data from it's data sheet.
You could code that by modify an example provided in cookbook.
Just steal all the init config code and modify example to poll forever reading 
the slave status register for known value if you get that working first time 
I'd be proud.
It's more than likely this code will not work as Linux didn't mux like you 
wanted let be positive.
Of course simplest way of it all works is you use exact what he's using for 
linux in cookbook and same slave device and wire it correctly 
It's worth buying everything he has exactly same hardware who knows maybe then 
he can help🤪🤔 if you post.
To me the important parts are understanding exactly what the PRU examples are 
doing specific to register addresses and correlation that the addresses match 
the TRM and you understand the bits being manipulated in registers by cross 
reference TRM.
Every device driver uses same idea.
The power of this is then you can write an I2C device driver for ARM core as 
well of course address change in TRM 
To be honest a device driver on a bare Bones ARM core is much more straight 
forward.
Using PRU now you have to decipher whether linux set up I2C mux correctly on 
ARM. 
That's really backwards having 2 processor's configuring a device. Especially 
the way it's done in Linux
Now factor in you need the data to be shared outside the chip you have all the 
Linux virtual address crap it's a mess.
Did you know they have SOC same arm cores plus DSP. both cores can run  in hard 
realtime fast no PRU both DSP and and ARM can use I2C and  share Data in shared 
memory very simple to understand and fast you know why?You don't have an 
albatross called Linux on the arm 🤔 The downside is these RTOS cost $ or 
using bare Bones you need device driver's
Linux is good but it's meant for Stuff that's not hard realtime that's probably 
why the PRU was added.
Anyway you have what you have to use so better to be positive and work through 
it unfortunately I know zero about DTS dtbo etc etc.I do know uboot.Let's 
accumulate as much I2C c code as possible for BBB is good.
You do know they may have both interrupt and polled I2C examples for ARM and 
maybe PRU in starterware? These are Best to understand how I2C is done as far 
as address of registers and values in config register's.
I'll do some digging for c code examples it be good refresher course for me. I 
did this for 32 year's I'm old hahaha I miss it.
Keep us posted ☺️








Sent from Yahoo Mail on Android 
 
  On Thu, Jan 21, 2021 at 5:59 PM, Pedro Henrique Fonseca 
Bertoleti wrote:   Hi Mark.
First of all, thank you for all the information. I've learnt a lot.After making 
some reads about PRU in AM335x TRM,  I've confirmed PRU can access various SIP 
peripherals, including the I2C interfaces (thank god! Bit-banging an I2C would 
be boring as hell).
Per my understanding (and accordingly to pru cook book), I2C2 (for example) is 
mapped into 0x4819C000 memory address. Also, configuration registers must be 
set in another registers to make I2C2 work properly (I'm trying to understand 
them now).
Please, correct me if I'm wrong: If I write/read data from 0x4819C000, I'll be 
able to communicate via I2C2 inside PRU, right? 
Also: once I2C2 is up and running in Linux side (= it has been configured at 
some time during bootloader initialization), is it enough for me to yse I2C2 in 
PRU by just writting and reading the address 0x4819C000?
Sorry if I understood it wrong.

Best Regards,Pedro Bertoleti
Em qui, 21 de jan de 2021 20:27, 'Mark Lazarewicz' via BeagleBoard 
 escreveu:

 Hello Pedro 
The thread I found turned into a big argument it looks like thats why I 
remembered it and made a reference to too many cooks giving advice. I will 
provide link but I am having trouble finding entire thread in the mail archive
[beagleboard] Re: Problems Reconfiguring GPIO's


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[beagleboard] Re: Problems Reconfiguring GPIO's


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As you see some m