EGWU on the road to USB JTAG debugging

The reason I wasnt seeing a clock on CLKOUT pin (NXP cortex-m3) was because on default OSC_EN and CLK_OUT are turned off. Why would this make any sense? Well NXP's ARM chips include an onboard RC oscillator.

Its 8Mhz for the cortex-M3 variants. So technically you could run a small embedded system without an external oscillator or crystal.

You wont be able to deal with precise timing but for a system that doesnt require it, this would suffice.

But even before that I have got to get JTAG communication working. I could go the pin header route (the 7 pins of P8) are tied to the 5 JTAG pins on the lpc1778 and to 3.3v and gnd. I have got the Olimex JTAG dongle and I can rig up male to female pin header cables to attach to the P8 connector on the board.

But I dont want to do that. That would defeat the purpose of putting an FTD2232H on the board. Not a cheap IC by any means.

OpenOCD supports USBJTAG. I knew this going in but I didnt check its GPIO mapping to see if its identical to mine. In either case its programmable so Ill end up probably having to recompile openocd 0.8.0 later anyway.

For now my primary goal was just to verify that once I plugged in a cable between my Linux development laptop and EGWU's J4 mini-USB connector, it enumerates correctly. Easy to verify with "lsusb"

AND it does


rombios@igboembedded:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub

rombios@igboembedded:~$ lsusb
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Bus 001 Device 002: ID 0403:6010 Future Technology Devices International, Ltd FT2232C Dual USB-UART/FIFO IC

rombios@igboembedded:~$ dmesg |tail
[  148.324678] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB0
[  148.324702] ftdi_sio 1-1:1.1: FTDI USB Serial Device converter detected
[  148.325218] usb 1-1: Detected FT2232H
[  148.325222] usb 1-1: Number of endpoints 2
[  148.325225] usb 1-1: Endpoint 1 MaxPacketSize 512
[  148.325228] usb 1-1: Endpoint 2 MaxPacketSize 512
[  148.325231] usb 1-1: Setting MaxPacketSize 512
[  148.327030] usb 1-1: FTDI USB Serial Device converter now attached to ttyUSB1
[  148.327343] usbcore: registered new interface driver ftdi_sio
[  148.327347] ftdi_sio: v1.6.0:USB FTDI Serial Converters Driver