I'm trying to flash the Olimex with an FTDI cable.
1) Do you have a procedure for that instead of using the ARM-USB-OCD?
2) When I remove wires TTMS and/or TTCK from ARM-USB-OCD, flashrom doesn't recognize the flash device. Is it necessary to flash or is specific to the ARM-USB-OCD ?
In other words, to flash we need at least, VREF, GND, TXD (TTDO), RXD (TTDI) but are wires TTMS and TTCK necessary for another flashing device than the ARM-USB-OCD ?
To use JTAG you need - obviously! - all its signals.
If your "FTDI cable" isn't JTAG then how do you expect it to work? ? ? ?
Thanks for your answer.
I'm not at all familiar with FTDI, JTAG, etc.
I'm grasping information as I'm testing and asking...
From your answer I understand that :
1) some FTDI cables are JTAG compatible and some others are not ?
I just checked the datasheets of different FTDI chips and it looks like they indeed support ot not JTAG.
2) do I need JTAG to flash the Olimex ? It can't be done otherwise ?
What does its manual(s) say? Also, their wiki.
What do the chip maker's manual(s) say?
I suppose also why do you want to flash it at all?
I'm not sure what exactly "FTDI cable" means.
However, when it comes to FTDI chips: our OpenOCD JTAG debuggers have FTDI chips inside, as indicated in the user's manual of the tools. FTDI chips are a major component in the design of our OpenOCD debuggers, but they are not the only component in the design. There are a lot of components. So it is incorrect to assume that FTDI = JTAG debugger. These are not equal.
Note that you also need compatible software for your hardware. If you manage to fix something with the FTDI cable that you have (on a breadboard or via soldering) you would also need to write proper software support for your tool, else it won't work with the software tools that we have suggested in our guides.
Thanks for your explanation Lub.
Could you please tell me :
1) what is RST_RT used for ? I guess it is to isolate the Olimex from the rest of the board in flash mode ?
2) why is it not wired to TSRST_N ? ( https://www.olimex.com/wiki/File:Arm-usb-ocd.png )
Is the manual Chapter 5 etc no help?
Are you talking about the ARM-USB-OCD manual ( https://www.olimex.com/Products/ARM/JTAG/_resources/ARM-USB-OCD_and_OCD_H_manual.pdf )?
In this case, what am I supposed to see in Chapter 5 ?
It's only weblinks and document revision.
I have been through the rest of the manual but there's no precision of what RST_RT does.
This document: https://www.olimex.com/Products/OLinuXino/RT5350F/RT5350F-OLinuXino/resources/RTF5350F-OLinuXino-UM.pdf
RST_RT can be used for hardware reset, and you can even place a button there in order to be able to easily perform a hardware reset (in case of a hang that might be useful). Also you can keep such a button pressed for when you need to program the board. Also under the picture with the connection between ARM-USB-OCD and RT5350F-OLinuXino-EVB you can also see this text:
"RST_RT jumper MUST be closed. Then power the board to become ready writing"
As always, your answer gives a clear complete explanation.
Thanks for pointing to the RT5350F-Olinuxino user manual, which I must have come across but completely missed of sight.
Neither RT5350F-OLinuXino, nor RT5350F-OLinuXino-EVB have hardware reset circuit
implemented. Should you need hardware reset, you can use the two pinholes named "RST_RT" on
the RT5350F-OLinuXino-EVB board (on the top side, near UART0 debug pins). "RST_RT" has
two pinholes - the first one is routed to PORSTN (pin #15 of EXT3 connector; processor pin C10).
Nearby you can also find a standalone RST pinhole exposed (only PORSTN).
It is a good practice to perform software reset of the board. Performing a hardware reset or power-
cycling the board (reset by disconnecting and re-applying the main power supply) might lead to
software corruption of the operating system.
I understand that pin#15 is connected to PORST_N and it must be connected to ground to trigger a reset.
My last question:
Is it possible to flash the RT5350F-Olinuxino without keeping it in reset mode? If yes, does it imply some risks such as having a corrupted firmware flashed? In other words, what is the risk of flashing it without cabling pin#15 of EXT3 connector to the ground?
@JohnS, while your answers give pointers to the poster as where to search for information (which is helpful in a way), they would be much more helpful if they were less elusive... Thanks for your interest in my topic :-)
I answer myself.
If you try to flash without putting pin#15 to GND, you don't risk anything. Flashrom won't recognize the flash device :
Quoteflashrom v0.9.9-r1954 on Linux 4.4.0-83-generic (x86_64)
flashrom is free software, get the source code at https://flashrom.org
Calibrating delay loop... OK.
No EEPROM/flash device found.
Note: flashrom can never write if the flash chip isn't found automatically.