imxrt1062 JTAG_MOD Pin Unconnected

[cboschert]

Hello,

We designed a board leaving the JTAG_MOD pin unconnected. We are just using SWDIO/SWCLK to interface with the IC. We missed the JTAG_MOD pin in design. We should have connected it directly to ground, but the PCBs have already been ordered. Does the JTAG pin need a strong pull-down connection to ground, or can the weak 100K pull down suffice? 

cboschert_0-1769095784752.png

cboschert_1-1769095801962.png

[EdwinHz]

Hi @cboschert,

As mentioned on the following community post (Solved: JTAG_MOD Pull Down Resistor Requirements for MX RT1010 - NXP Community) the JTAG_MOD pin is the base to determine the mode for JTAG functionality. By using a strong pull-down connection to ground, we ensure consistency even across noisy environments, and therefore we can assure the JTAG capabilities will function as expected. If a weak pull-down were to be used instead, there is much higher probability that noise might affect the JTAG_MOD pin and cause unexpected behavior on the JTAG functionality as a whole.

BR,
Edwin.