In grave need of JTAG debugging demystification

Questions » In grave need of JTAG debugging demystification

Liam James

11 years ago.

If I have a PCB with an LPC1768 acting as the microcontroller how would I use JTAG/SWD to upload programs and debug? From what I understand I first have to export my code from the web-based mbed compiler to a secondary offline compiler like Code_red or Keil, but how does the actual connection take place?

P.S

Unrelated question: What is FTDI and TTL? I'm very new to hardware and microcontrollers in general.

1 Answer

X M

11 years ago.

If you have exported your code to an offline compiler , you can make changes and compile locally . Once you have compiled your program you download it using the IDE , the compiler's environment . However you need a "debugger " connection to use the debugging options . This can be done with a Jtag / SWD interface ( such as Keil ulink etc ... or Segger j-link ) or through a CMSIS-DAP interface

Mbed board allready incorporates such an interface using the "magic" chip ( the other ARM chip on the mbed board except LPC 1768 ) , so it is the most affordable option .

for more debugger interface info , have a look at these :

http://www.keil.com/arm/ulink/

http://www.segger.com/jlink.html

http://mbed.org/handbook/CMSIS-DAP

and http://www.keil.com/mcb1700/ for an other prototype board using lpc1768 , very well documented

FTDI232RL is a serial to usb interface chip , accepting TTL levels. For more info on TTL / 232 voltage levels refer to https://www.sparkfun.com/tutorials/215

Regards , Christos

Liam James

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11 years ago.