Using ACLK_EXSC for the iMX6 EIM bus

[shonysinay]

Hi all,

I am going to use the iMX6 EIM module as external bus to control my on-board parallel bus based hardware.

I have to configure the EIM as 16bit multiplexed bus and i need to use FPGA to convert it to 33Mhz non-multiplexed bus.

For this purpose i need a clock which is synchronizes with the bus timing. I guess that the ACLK_EXSC option should be used. 

My question is: Can i configure the EIM_BCLK pad to be the ACLK_EXSC? if not, what pads can be configured as ACLK_EXSC and how?

Thanks,

Shony

[igorpadykov]

Hi Shony

unfortunately ACLK_EXSC is not routed on external pad.

BCLK can not be configured as ACLK_EXSC. Probably

outputting aclk_eim_slow_clk_root on CCM_CLKO1,2

using CCM_CCOSR register, will suit your needs.

Best regards

igor

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[shonysinay]

Thank you Igor for your reply.

I need this clock to be only 33Mhz, but the 'System Clock Frequency Values' in Table 18-4 of the reference manual says that the default frequency of the ACLK_EIM_SLOW_CLK_ROOT is 396Mhz. How i can reduce it as close as possible to my needs?

I also found in paragraph 'Clocks' 22.3 the following statement ' ACLK_EXSC: Clock created from EIM clock for External device usage. Integer division by 1, 2, 3 and 4 of the clock can be use with BCD bit field configuration, according to external devices demands'. !

Shony

[igorpadykov]

clock can be changed by reprogramming PLL, please check

CCM Chapter of RM.

Best regards

igor

[shonysinay]

OK.

Thanks again.