CC3235MODASF: power on reset issue

Vidula Saxena

Part Number: CC3235MODASF
Other Parts Discussed in Thread: UNIFLASH, CC3235SF

Hi Ti memers,

We ahe developed a custom board in which we have used cc32335modasf. We programmed it using cc32335sf leaunchpad.

first we programmed it via uniflash to enable developement mode then we programmed the application image from ccs "flash". while flashing from ccs we modified the "image.syscfg", wherein we changed the module type to Antenna module (default was I/C) and then programmed the file. the entire process is ok the application runs fine. But when we power on/off the custom board, the module does not work. we have to reset it externaly by giving low on nReset pin. Just for your reference we have connetced VBAT_RESET to VCC3.3V. We also tried connecting a 100kpullup and 0.1uF cap in nReset pin still the module hangs on power on reset.

If you want for your reference we can share schematic privately

over 1 year ago

0 Jan D over 1 year ago

Guru 80445 points

Hi,

What SOP mode do you use? If it is used SOP mode 0-1-0 make sure that you have pull-up at RX line.

If you want to review of your hardware please contact TI here.

Jan

0 Vidula Saxena over 1 year ago in reply to Jan D

Prodigy 20 points

sop is 010

0 Jan D over 1 year ago in reply to Vidula Saxena

Guru 80445 points

Hi,

Make sure that your RX line is at high state during boot.

Jan

0 Vidula Saxena over 1 year ago in reply to Vidula Saxena

Prodigy 20 points

if we dont use TX and RX of cc3235sf(pin 46 and pin 47) after programming still do we need to place pull up on RX? Not able to understand how it is affecting reset functionality?

do we need to place anything on nReset pin?

+1 Jan D over 1 year ago in reply to Vidula Saxena

Guru 80445 points

Hi,

At SOP mode 0-1-0 is uart-loader (programming mode) determined by state of RX pin. When is pin low module is expecting programming by UART and your code not start. When RX is not connected (floating input) it can errantly enter to programming mode. You have options:

use weak pull-up at RX line (let say 10k)
change SOP mode (for more details about SOP modes see datasheet)

Jan

0 Vidula Saxena over 1 year ago in reply to Jan D

Prodigy 20 points

Thanks for your response. I just wnated to know if i keep sop 000 my device resets on power ON but i am unable to fkash is from ccs and also it does not connect from Uniflash application. however if i disable "image creator" from properties then i am ale to debug the program. please provide information on this.

0 Jan D over 1 year ago in reply to Vidula Saxena

Guru 80445 points

Hi,

This is expected behaviour. For debug from CCS is used JTAG/SWD but sFlash programming is done via UART and bootloader. Bootloader mode is set by SOP mode. At SOP mode 0-0-0 is programming via bootloder not allowed. SOP modes:

Jan

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CC3235MODASF: power on reset issue