On Thu Apr 5 06:31:36 CEST 2012, Peter Stuge wrote:
I will try to make my VHDL cores so they will be compatible with both types of boards. I plan to start with UART over USB support for the currently available Papilio boards.
UART is stoneage idiotic useless. It's 2012, so please aim higher.
Yet another opinion I guess; at the end of the day opinions should not matter.
Basically flashrom SPI access, POST code access and serial console access. This 'playground' should eventually give me enough insight in an optimal implementation when targeting future boards.
Don't invent yet another packet protocol on top of a serial stream, do this right the first time. You're planning on implementing three different functions, and they really do need to use different interfaces.
Do not worry. No need for assumptions. I was not planning to.
I will write a number of VHDL cores that plug in to a Wishbone interface that will also be connected to a USB controller. In the first version that controller will be a (circuit-switched) UART over USB controller (switched either manually or by means of routing an extra GPIO pin of the FT2232D to the FPGA).
Future boards is expected to contain improved USB hardware in several flavors ranging from a USB transceiver-only approach with USB stack in FPGA, to an FT232H in MPSSE mode, to a dedicated microprocesser with build-in USB and anything in between. It should not matter what kind of hardware is used as long as it contains a similar Wishbone interface it will be transparant to the rest of the Wishbone cores.
Thank you for the QiProg info.
For the SPI flash emulator, suggest use IS61WV20488BLL-10TLI.
The first prototype will not contain SRAM, but merely act as an SPI master mux. Due to its complexity, cost and GPIO pin count, I will only consider SRAM if absolutely necessary.