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omap_hdq / 1-wire

Lorenzo Salvadori
Prodigy 130 points
Other Parts Discussed in Thread: DM3730

Hi,

I'm trying to configure the DM3730 processor to use the communication 1-wire with a battery.

I'm using kernel 2.6.32 based on evm board (ti-dvsdk_dm3730-evm_4_02_00_06).

Regarding HW composition I mounted a pull-up resistor of 4.7K as recommended by specification.


In mux.h of u-boot I have configured

#define CONTROL_PADCONF_HDQ_SIO        0x01C6

In evm.h

   MUX_VAL(CP(HDQ_SIO),            (IDIS | PTU | EN  | M0))

I checked in the reference manual that M0 corresponds to "hdq_sio" and M4 corresponds to "gpio_170"


Now I am connected with an oscilloscope to the bus (instead of battery) then, if I try to drive the gpio 170, I am able to see the signal change, so the connection seems to be ok.

If I reboot and, without the battery connected,I read in oscilloscope 3.3V.

I launch omap_hdq using:

root@dm37x-evm:~# modprobe omap_hdq

omap_hdq omap_hdq.0: OMAP HDQ Hardware Rev 0.5. Driver in Interrupt mode

I do not  see any change state from the oscilloscope.


If I check with 

root@dm37x-evm:~# ls  /sys/bus/w1/devices

i see 2 directories came up after modprobe:

01-000000000000 

w1 bus master


root@dm37x-evm:~# ls  /sys/bus/w1/devices/01-000000000000

driver     id         name       power      subsystem  uevent

root@dm37x-evm:~# ls /sys/devices/w1\ bus\ master/

01-000000000000                           w1_master_name                                       
driver                                                   w1_master_pointer                                    
power                                                  w1_master_pullup                                     
subsystem                                          w1_master_remove                                     
uevent                                                 w1_master_search                                     
w1_master_add                                w1_master_slave_count                                
w1_master_attempts                        w1_master_slaves                                     
w1_master_max_slave_count       w1_master_timeout

My question is it is possible that during the scan does not see change the status of the signal on the oscilloscope?

thanks, Lorenzo

  • 0
    Guru 31670 points

    Lorenzo,

    Can you go into the driver code and see the xxx_probe() function and see whether its issuing any transfers from the fuel gauge using HDQ? Also can you verify once again that the PAD settings for the pin in M0 only?