Minimum SWD Debug pins for i.MXRT1064 w /LPC-Link2

cancel
Showing results for 
Show  only  | Search instead for 
Did you mean: 

Minimum SWD Debug pins for i.MXRT1064 w /LPC-Link2

1,302 Views
bennxp
Contributor III

I'm confused about what pins are necessary to get SWD debugging working with the i.MXRT1064. (I will be using LPC-Link2). All the documentation I can find is for JTAG.

Do I need to keep JTAG_MOD (GPIO_AD_B0_08) low for SWD mode? The CEC manual says:

JTAG_MOD set to hi configures the JTAG interface to mode compliant with IEEE1149.1 standard.
JTAG_MOD set to low configures the JTAG interface for common SW debug adding all the system
TAPs to the chain.

but if this is a JTAG pin and JTAG isn't active, is this relevant? 

Do I need a reset pin? I can't find anything that says SWD needs a reset pin in the manual, but I've read online that you do need a reset pin. If, so would that be JTAG_TRSTB (GPIO_AD_B0_11) or is that JTAG specific? If so, is there another reset I should use (ONOFF?)

Also, do I need pull-up or pull-downs on the SWD_DIO and SWD_CLK pins? The CEC manual (Table 4) for JTAG says that JTAG_TMS (same pin as SWD_DIO) needs 47k pull-up and that JTAG_TCK (same pins as SWD_CLK) needs a 100k pull-down, but does this apply for SWD as well?

I'm assuming I can ignore the SWO pin as the i.MXRT does not mention it.

And finally, do I need to bring out VCC ("JTAG_VREF") for SWD debugging? Again, my plan is to use the LPC-Link2 and connect the process to it via 10-pin 'jtag' connector J7.

Thanks!

Ben

Labels (1)
0 Kudos
1 Reply

1,241 Views
FelipeGarcia
NXP Employee
NXP Employee

Hello Ben,

 

I recommend you to check the blog below from a colleague where it gives a general explanation about SWD required connections. Reset is needed and SWO is optional.

 

Using the FRDM-K64F with CodeWarrior | MCU on Eclipse

 

Also, please check the following link to see the SWD connection recommendation according to Arm Cortex Debug specification.

Documentation – Arm Developer

Hope it helps!

 

Best regards,

Felipe

-------------------------------------------------------------------------------

Note:

- If this post answers your question, please click the "Mark Correct" button. Thank you!\

- We are following threads for 7 weeks after the last post, later replies are ignored.

Please open a new thread and refer to the closed one, if you have a related question at a later point in time.

------------------------------------------------------------------------------ 

0 Kudos