LPC MicrocontrollersのトピックLPC54608 eva board ISP,SDRAM pin https://community.nxp.com/t5/LPC-Microcontrollers/LPC54608-eva-board-ISP-SDRAM-pin/m-p/1000305#M39301 <HTML><HEAD></HEAD><BODY><P>CPU packege is&nbsp;180-pin, TFBGA&nbsp; in OM13092 board</P><P><SPAN lang="en">C8 pin is connected to SDRAM and ISP switch</SPAN>.</P><P><SPAN lang="en">There is a 2.2K resistor(R108) between the ISP switch and the CPU.</SPAN></P><P><SPAN lang="en">Why are you using a 2.2K resistor?</SPAN></P><P><SPAN lang="en"></SPAN></P><P><SPAN lang="en">Shouldn't it be a 0 ohm resistor?</SPAN></P></BODY></HTML> Sat, 21 Mar 2020 06:18:24 GMT 実奥山 2020-03-21T06:18:24Z LPC54608 eva board ISP,SDRAM pin https://community.nxp.com/t5/LPC-Microcontrollers/LPC54608-eva-board-ISP-SDRAM-pin/m-p/1000305#M39301 <HTML><HEAD></HEAD><BODY><P>CPU packege is&nbsp;180-pin, TFBGA&nbsp; in OM13092 board</P><P><SPAN lang="en">C8 pin is connected to SDRAM and ISP switch</SPAN>.</P><P><SPAN lang="en">There is a 2.2K resistor(R108) between the ISP switch and the CPU.</SPAN></P><P><SPAN lang="en">Why are you using a 2.2K resistor?</SPAN></P><P><SPAN lang="en"></SPAN></P><P><SPAN lang="en">Shouldn't it be a 0 ohm resistor?</SPAN></P></BODY></HTML> Sat, 21 Mar 2020 06:18:24 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC54608-eva-board-ISP-SDRAM-pin/m-p/1000305#M39301 実奥山 2020-03-21T06:18:24Z Re: LPC54608 eva board ISP,SDRAM pin https://community.nxp.com/t5/LPC-Microcontrollers/LPC54608-eva-board-ISP-SDRAM-pin/m-p/1000306#M39302 <HTML><HEAD></HEAD><BODY><P>My guess would be to protect the CPU if the ISP switch is pressed while the pin is used for accessing SDRAM. The 2.2K resistor will limit the current if switch is pressed during SDRAM access, at the same time its value is low enough to pull the pin low during boot (and activate ISP)</P></BODY></HTML> Sat, 21 Mar 2020 11:22:47 GMT https://community.nxp.com/t5/LPC-Microcontrollers/LPC54608-eva-board-ISP-SDRAM-pin/m-p/1000306#M39302 carstengroen 2020-03-21T11:22:47Z