TMS320DM8127: DM8127: Using only 16 bit DDR3 instead of 32bit DDR3

TIDR

Part Number: TMS320DM8127

My customer is planning on using only 16-bit DDR3 interface. The 16 bit mode is supported according to the TRM by setting narrow mode field in SDRCR. However, there is not information about hardware configuration for 16 bit interface support.

Is there any recommendation on unused pin termination for DDR3? I assume lower numbered data lines are used ie D0:D15 are connected to the memory device? How do unused DQS and DQM lines need to be terminated?

Thanks!

over 8 years ago

0 Prashant A over 8 years ago

Intellectual 760 points

Hi TIDR,

The query has been forwarded to respective team member.

Regards,
Prashant
Pathpartner Technology Pvt. Ltd.

0 Pavel Botev over 8 years ago

TI__Guru**** 170625 points

TIDR,

You should refer to DM8127 datasheet, see section "9.13.4.2 DDR3 Routing Specifications"

Regards,
Pavel

0 TIDR over 7 years ago in reply to Pavel Botev

TI__Genius 9355 points

Hi Pavel,

Thanks! I found the info now. However, the device pin table indicates that the DQS are connected to IPU and DQS (inverted) to IPD. The unused data info says to tie them off differently. Is this a typo?

Whereas the section 9.13.4.2 says:

Is this correct or is this a typo? Is the unused pin tie-off in different polarity than internal pulls?

0 Pavel Botev over 7 years ago in reply to TIDR

TI__Guru**** 170625 points

TIDR,

Per mine understanding, DM8127 datasheet states:

DQS+ to DVDD_DDR[x] supply via a 1-kΩ resistor
DQS- to ground via a 1k-Ω resistor
DDR3 data unused pins can be left unconnected.

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TMS320DM8127: DM8127: Using only 16 bit DDR3 instead of 32bit DDR3