I'm getting close to taking my breadboarded product and converting it into a schematic for PCB layout and PCBA manufacture. The hardware works fine and the fundamental software is running, however there is one hitch. What is the best way to load and upgrade software, interface to the hardware for debugging and retain the valuable USB device port. The best way appears to implement an ICDI on the product.
Let me tell you a bit about the product. The product that has been developed is a low volume product so an extra $20 to include the ICDI on each product is not a problem. I should also point out that the product has two TM4C129x microcontrollers with one microcontroller being the executive processor. I'll need to software download to both microcontrollers. It would be nice to have debug facilities for both microcontrollers and I need one USB device port for the product's use. The product also has a USB host for data logging onto a USB memory stick, but this comes directly off one of the Tiva microcontrollers.
There appears to be two ways to implement the ICDI:
1) Use the FTDI FT2232D chip and a controlled switch (or a FT4232H, which is the quad version of the FT2232D). This requires a support 93C46 EEPROM, 6 MHz crystal and three 74LVC125A buffer/driver/transceiver. Quiet a lot of circuitry! This is the method used on the LM3S9D96 Development Kit
2) Use a Tiva microcontroller plus crystal with appropriate software. This is the method used on the Tiva Launchpad.
The FTDI chip costs more than the Tiva microcontroller and then there's all the extra support circuitry. The ideal solution appears to be to use a Tiva microcontroller, particularly considering that I need to service tow microcontrollers.
The problem is I need to the software to make it work. Is the source code available? Can it be made available? Everyone who produces a Tiva based product will have to address the issue of how to download new softare. Having debug capability and an extra USB device port are great free bonuses. Would be a great marketing move.
Is there any reason for not releasing the Tiva-based ICDI software?