WL1271 (TiWi-R2) Power-up Sequence

Inderjit Bains

Expert 2745 points

Other Parts Discussed in Thread: AM1808, WL1271

A couple of questions:

1. Can VDD (1.8V) come up before VBAT (3.3V)?

2. Can SDIO_CLK be active before WL_EN?

Inderjit

over 13 years ago

0 Eyal a over 13 years ago

TI__Genius 9240 points

Hi Inderjit,

Voltage and Slow clock should be enabled before WLAN enable.

In addition the SDIO clock should only be valid after the voltages (1.8V) and WLAN_EN and already present.

Regards,

Eyal

0 Inderjit Bains over 13 years ago in reply to Eyal a

Expert 2745 points

Just to confirm: does the order in which VBAT (3.3V) and VIO (1.8) ramp up matter? Will VIO before VBAT damage the WL1271? The order is VIO before VBAT because the AM1808 requires that the 1.8V supply be up before the 3.3V supply.

Also, with PSP03.21.00.04.sdk (AM1808), SDIO clock is valid before WLAN_EN from the testing I've done. Can you confirm that this is the case?

0 Arild Kolsrud over 13 years ago in reply to Inderjit Bains

TI__Intellectual 1340 points

Inderjit:

Please see attached WLAN power up sequence figure.

Arild0118.WLAN power up sequence.pdf

0 Inderjit Bains over 13 years ago in reply to Arild Kolsrud

Expert 2745 points

Thanks, but it doesn't answer my question: will VIO power-up before VBAT damage the WL1271?

0 Inderjit Bains over 13 years ago in reply to Inderjit Bains

Expert 2745 points

Any progress on this?

0 Arild Kolsrud over 13 years ago in reply to Inderjit Bains

TI__Intellectual 1340 points

Hi Inderjit:

The device will not be damaged if VIO comes up before Vbat. However, before the Enable is going high, the VIO, Vbat and Slow_Clock must be present and stable.

Sincerely,

Arild

Wi-Fi

Wi-Fi forum

WL1271 (TiWi-R2) Power-up Sequence