Re: [beagleboard] See if I understand setting up a device tree for the PRU

2017-05-24 Thread Charles Steinkuehler
On 5/17/2017 9:37 PM, Clark Sann wrote:
> 
> Signal  Signal name on  Mode from Data
>  Octavo per BB Blue   Sheet Table 4-1
>  schematic
> 
> MDIR 1A GPIO2_0_T13  7
> MDIR 1B UART4_TX0_U176
> MDIR 2A CP101_16_R137
> MDIR 2B LCD_DATA14_V40
> PWM 1A  EHRPWM1A_U14   6
> 
> The mode setting I have chosen is the mode that causes the pin to have the 
> signal name shown on the BB Blue schematic.
> 
> Do I have my mode settings correct?

Probably not, unless you plan to use the UART, PWM, and LCD hardware
to drive your motor coils.

You probably want to set all the pins to mode 7 (GPIO).  The PRU can
write to the GPIO control registers with minimal delay and latency.

-- 
Charles Steinkuehler
char...@steinkuehler.net

-- 
For more options, visit http://beagleboard.org/discuss
--- 
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/bfc90fcf-e962-d70c-615a-185fb683f189%40steinkuehler.net.
For more options, visit https://groups.google.com/d/optout.


[beagleboard] See if I understand setting up a device tree for the PRU

2017-05-17 Thread Clark Sann
I am trying to determine how to use the PRU to control the DC motors on a 
BB Blue. I plan to use these 4 H-bridges to control two stepper motors. The 
PRU will generate the proper sequence of outputs to move the stepper at the 
proper speed, direction, and amount of rotation.

After examining the BB Blue schematic, I found I need to control the 
following signals: MDIR 1A, 1B, 2A, 2B, 3A, 3B, 4A & 4B, MOT_STBY, PWM 1A, 
1B, 2A, & 2B.

After examining the Sitara Data Sheet, Table 4-1, I found I need to 
configure the device tree to set the modes as follows (for simplicity, only 
a subset of the signals shown):

Signal  Signal name on  Mode from Data 
 
Octavo per BB Blue   Sheet Table 4-1
schematic

MDIR 1A GPIO2_0_T13  7 

MDIR 1B UART4_TX0_U176 

MDIR 2A CP101_16_R137   
  
MDIR 2B LCD_DATA14_V40 
 
PWM 1A  EHRPWM1A_U14   6

The mode setting I have chosen is the mode that causes the pin to have the 
signal name shown on the BB Blue schematic. 

Do I have my mode settings correct?

I do not yet understand how to access the signals from the PRU...I will 
continue with that if I am correct so far. I do understand that I need to 
determine the host memory address for each signal. Am I on the right track?

Incidentally, assuming I understand the above, I have found what appear to 
be errors in the BB Blue Pin Table. I would like to correct it. How would I 
do that? I would like to submit my changes to someone (I'd colorize the 
cells I changed) who can verify what I've done before putting it in the 
wiki.

Clark






-- 
For more options, visit http://beagleboard.org/discuss
--- 
You received this message because you are subscribed to the Google Groups 
"BeagleBoard" group.
To unsubscribe from this group and stop receiving emails from it, send an email 
to beagleboard+unsubscr...@googlegroups.com.
To view this discussion on the web visit 
https://groups.google.com/d/msgid/beagleboard/d2e2a190-7dcb-4942-9cbb-676fb3b5dd6e%40googlegroups.com.
For more options, visit https://groups.google.com/d/optout.