topic Re: iMX 6 EIM clock in i.MX Processors

iMX 6 EIM clock

host1 — Sat, 25 Mar 2023 21:10:57 GMT

Hello,
I want to use the EIM interface of the i.MX 6 to communicate with an External FPGA.
My aplication requires using Asynchronuos Mode as described in section 22.1.2.1 (page 986) of the IMX6SDLRM.pdf document.
I need the EIM interface to work at 43.75 MHz.
Table 22-2 mentions a clock named EIM_ACLK_FREERUN and specifies that it's an input to the device.

Question:

1. Can I provide a 43.75MHz clock signal (from an external oscilator) to one of the pins that drive EIM_ACLK_FREERUN ?
2. Why isn't EIM_ACLK_FREERUN mentioned in Table 22-4 (page 994) which describes the clock sources for EIM ?

Re: iMX 6 EIM clock

Harvey021 — Tue, 28 Mar 2023 10:12:14 GMT

Hi @host1

Do not use EIM_ACLK_FREERUN，should use BCLK pin for FPGA, it's default clock(ROOT clock) is 132MHz, when it divided by 3, BCLK will be 44MHz, and BCLK is a continuous clock , just for external FPGA.

Best regards

Harvey

Re: iMX 6 EIM clock

host1 — Tue, 28 Mar 2023 14:15:37 GMT

Hello @Harvey021 and thanks for commenting.

I need it to be EXACTLY 43.75 MHz and I already have an oscillator in the system that uses this frequency.

Is it somehow possible drive the EIM using this external 43.75 MHz signal ?

Re: iMX 6 EIM clock

Harvey021 — Thu, 30 Mar 2023 03:10:36 GMT

Due to no reference design for EIM_ACLK_FREERUN, we'd suggest you'd better reserve it's circuit for debugging purpose. the figure may be a reference.

Best regards

Harvey

Re: iMX 6 EIM clock

host1 — Sun, 02 Apr 2023 12:48:14 GMT

I need it to be EXACTLY 43.75 MHz and I already have an oscillator in the system that uses this frequency.

Is it somehow possible drive the EIM using this external 43.75 MHz signal ?

Re: iMX 6 EIM clock

Harvey021 — Mon, 03 Apr 2023 05:36:49 GMT

Because of the FREERUN we don't have a test example. Please refer to the previous post for a test.

Best regards

Harvey

Re: iMX 6 EIM clock

host1 — Mon, 03 Apr 2023 12:41:30 GMT

Hi, which previous post ?
You mean the one you mentioned the clock will be 44MHz ?

I need it to be exactly 43.75 MHz...