AM5728: Interfacing DPRAM to GPMC

SAJEEVAN K8

Part Number: AM5728

Hi all,

I wanted to interface a DPRAM to AM572x EVM.

But when I check the schematics of AM572x EVM, it is found that, the pins gpmc_ad0 to gpmc_ad15(which are required for external interface) are used as System Boot Select pins.

Is there any alternative way for interfacing a DPRAM to AM572X EVM.

Also I would like to know, whether there is any other TI Processor EVM, in which GPMC pins are freely available for making interface to external devices in parallel mode, at the same, it should have HDMI output, SD card interface.

(In AM335x EVM also GPMC pins are utilized for other purpose )

Thanks for the help in advance.

Thanks & Regards,

Sajeevan.K

over 8 years ago

0 Biser Gatchev-XID over 8 years ago

TI__Guru**** 393215 points

Hi,

The fact that the GPMC interface is also SYSBOOT pins does not prevent you from using it. SYSBOOT values are latched in the processor only once, at reset release time.

0 SAJEEVAN K8 over 8 years ago in reply to Biser Gatchev-XID

Intellectual 330 points

Hi,

Thank You for the reply.

But now all these pins either connected to either Ground or +3.3V.
This states are required at Power ON, for correctly booting up from SD card or EMMC as required.

By keeping the pins in this state, initially and later make them floating requires some switching.
Switching 16 lines like this will be very difficult.

How it will be done?

Thanks for the help in advance.

Thanks & Regards,
Sajeevan.K

0 Biser Gatchev-XID over 8 years ago in reply to SAJEEVAN K8

TI__Guru**** 393215 points

These pins are pulled up/down with 10kOhm resistors, which are easily overridden when the pin is actively driven. No switching is required.

0 SAJEEVAN K8 over 8 years ago in reply to Biser Gatchev-XID

Intellectual 330 points

Hi Biser,

Thank You for the advice. This would solve the issue which we are facing.

Thanks & Regards,

Sajeevan.K

Processors

Processors forum

AM5728: Interfacing DPRAM to GPMC