topic [i.MX6] One question about PCIe I/F in i.MX Processors

[i.MX6] One question about PCIe I/F

Paul_Kang — Tue, 04 Jun 2013 00:56:00 GMT

I have one quesiton about PCIe circuit connection to i.MX6 device for proper PCI device operation. Could anybody answer to it?

The question is, actually, it is very clear about Sabre A (It only has PCIe data connection to mini PCI connector) I but in case of Sabre SD, I found there are some other signals connected to mini PCI connector.

Below is my understanding. If there is anything incorrect, please correct it.

PCIe_CRXM/P, PCIe_CTXM/P à PCIe interface
PCIe_CREFCLKM/P à CLK from CLK0_N/P or CLK1_N/P of i.MX6
PCIe_UIM_xxx à All for SIM card and not connected to i.MX6
PCIe_USBDM/P à USB HOST port of i.MX6
LED_xxxx_B à LED on board. Not connected to i.MX6
PCIe_DIS_B, PCIe_RST_B, PCIe_WAKE_B à GPIO, can be connected to any GPIO of i.MX6
PCIe_SMC_CLK/DAT à I2C I/F and connected to i.MX6 I2C I/F

Thank you!

Paul

Re: [i.MX6] One question about PCIe I/F

weidong_sun — Tue, 04 Jun 2013 03:39:51 GMT

Hello,jounnii,

On mini-PCIE(J1)connector of sabreSD board, there are 2 kinds of signals : One is PCIe signal; the other is 3G signal. Normally, definitions on mini-PCIE connector are for 3G module. But in order to connect PCIe signals in i.mx6 outside, designers used those reserved pins on J1 for PCIe signals.

PCIe signals are : CLK1P/CLK1N, PCIE_RXM/PCIE_RXP, PCIE_TXM/PCIE_TXP. PCIE_WAKE_B is a GPIO on i.mx6, you can changed it to another GPIO, and configure it as input.

Other signals on J1 are for 3G module.

Regards,

Weidong

Re: [i.MX6] One question about PCIe I/F

Paul_Kang — Tue, 04 Jun 2013 05:12:02 GMT

Hi Weidong,

Thank you for your answer.

Regarding 3G signal,

can I say, PCIe_DIS_B, PCIe_RST_B is GPIO and PCIe_SMC_CLK/DAT is I2C?

I am not sure if such additional signals are within PCIe standard or not.

Best regards,

Paul

Re: [i.MX6] One question about PCIe I/F

weidong_sun — Tue, 04 Jun 2013 06:15:52 GMT

Hello, jounnii,

>>can I say, PCIe_DIS_B, PCIe_RST_B is GPIO and PCIe_SMC_CLK/DAT is I2C?

Yes , right.

>>I am not sure if such additional signals are within PCIe standard or not.

additional signals are for 3G module. Not PCIe signals. you can confirm them by PCIe standard specification.

Don't confuse connector named mini-PCIe, mimi-PCIe is only a name for 3G module. But PCIe is a standard signal specificaion. For PCIe with 1 lane interface, it has 3 diffrential pairs : CLK+/CLK-, RX+/RX- and TX+/TX- .

Do I describe it clearly ?

Regards,

Weidong

Re: [i.MX6] One question about PCIe I/F

Paul_Kang — Tue, 04 Jun 2013 06:21:51 GMT

Hi, Weidong,

It is clceared now. thank you for your answer.