tverrbjelke:
In OpenOCD revision 247:in the readme.txt
I also found a confusing desription of Olimex-ARM-USB JTAG:
It states:
- Olimex ARM-USB-OCD: www.olimex.com
The Olimex ARM-USB-OCD offers support for a wide vriety of target voltages from
2.0V to 5V. It also allows targets to be powered from the ARM-USB-OCD and
features and additional RS232 UART.
Besides the marked typo,
I have one device and it’s documentation says
“supports ARM targets working in voltage range 2.0 – 5.0 V DC”
But power supply of that device one can jumper between 5, 9 and 12V!
So I am not sure if that is confusing only me… maybe one could explain how that works together!?
Is that “2-5V” related to the 20pin JTAG debug-interface?
How can the device adjust the 2-5 voltage, if I only can jumper the power voltage between 5/9/12V?
txh
You are actually refering to two separate things, the circuit board power supply and the ARM device operating voltage. The ARM-USB-OCD contains a power supply to supply voltage to the circuit board being tested. The circuit board being tested must also contain it’s own voltage regulator to provide power to the ARM device at the voltage that it needs. The ARM JTAG header has two pins that are at the same voltage as the ARM device on the circuit board. Those two pins determine the interface signal levels that will be used by the JTAG interface. So the “2-5V” specification is for the signal levels on the JTAG interface and the “5/9/12V” refers to the voltages available as raw power to the circuit board containing the ARM device.