[FAQ] AM625 / AM623 / AM644x / AM243x / AM62A / AM62P - Bootmode implementation with buffers

Kallikuppa Sreenivasa

Part Number: AM625

Tool/software:

Hi TI Experts,

Do you have any suggestion on configuring the bootmode pins for alternate functions? I am using the bootmode resistors + buffers to configure the SOC boot.

3 months ago

0 Kallikuppa Sreenivasa 3 months ago

TI__Guru**** 158129 points

Hi Board Designers,

the below diagram includes the following

Connection of bootmode resistors to the buffer input and connection of the buffer output through 1K series resistor is shown in the below diagram.

The bootmode pin from the SOC can be connected to the alternate function through a 0R resistor.

The 0R resistor can be used to isolate the alternat functions to test the bootmodes.

SOC_Bootmode_Configuration.pdf

Regards,

Sreenivasa

0 Kallikuppa Sreenivasa 3 months ago in reply to Kallikuppa Sreenivasa

TI__Guru**** 158129 points

Hi Board Designers,

Additional inputs

Connecting bootmode pins directly to supply
They should never connect any bidirectional IO directly to the power rail. There is a good chance the device output buffer would be damaged if the pin is connected directly to 3.3V and the output buffer is accidently driven low.
The N-channel FET may be damaged or the metal connecting the FET to the pin or VSS. Anytime you damage something in a device with these small geometries, the damage is very likely to spill over to adjacent circuits. So no guarantee the output buffer is the only thing damaged.

MCU_PORz or RESETSTATz to control bootmode buffers
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1352163/am67a-mcu_porz-or-resetstatz-to-control-bootmode-buffers/5160825?tisearch=e2e-sitesearch&keymatch=bootmode%252520buffer#5160825

the boot mode buffer
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1215011/am625-the-boot-mode-buffer/4585732?tisearch=e2e-sitesearch&keymatch=bootmode%2525252525252520buffer#4585732

Buffer on SOP boot mode pins
https://e2e.ti.com/support/microcontrollers/arm-based-microcontrollers-group/arm-based-microcontrollers/f/arm-based-microcontrollers-forum/1206852/am2634-buffer-on-sop-boot-mode-pins/4558332?tisearch=e2e-sitesearch&keymatch=bootmode%2520buffer#4558332

BOOTMODE Pin Sample Timing
https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1070744/dra821u-bootmode-pin-sample-timing?tisearch=e2e-sitesearch&keymatch=bootmode%2525252525252520buffer#

Regards,

Sreenivasa