It is utterly unacceptable that Atmel is shipping example code in 2011,
which doesn't support parts that are shipped still in 2016. They would
have had five years to fix their code to implement the chip errata :(
We need to refer to g_dfu as a pointer from all code. In DFU mode, it
gets assigned to the address of _g_dfu, which is placed by the linker
script at the start of RAM. In runtime mode, the pointer is statically
defined to point at the start of RAM. The linker script for the runtime
(dfu environment) is adjusted to save the first 32 bytes for the _g_dfu
structure.
* we now actually route the EP0 control requests in DFU mode to the
correct handler (weak linker symbols are tricky)
* we now actually call code to read/write data from/to RAM/FLASH
This way we can easily check with 'diff' for differences in our code and
Atmel softpack. Also, this layout is more suitable for building various
different firmware images (e.g. factory-test, dfu-loader, main
application) for a variety of different boards (simtrace, owhw, qmod).
The signals are driving an external NPN transistor, so the default state
must be low at reset to en sure that !PERST on the modem input is
de-asserted by default.
It seems like a lot of modems have rather long (100ms!) minimum reset
durations. Makes me wonder if it's an actual reset line or rather juts
some GPIO that they poll/sample every so often. Then there are other
modems that state the reset *must not* be longer than 1s. So let's
choose 300ms as a value in-between.
The PLL setting doesn't depend on the 'qmod' board type but on the
combination of the BOARD_MAINOSC and BOARD_MCK #defines. So let's
remove the '#ifdef qmod' from the equation.
The only 'qmod' specific part is whether or not to use the internal xtal
oscillator or not.
Table 42-31 ofd DOC6500 states that the minimum output frequency of the
PLL is 60 MHz. The existing qmod code violated this by configuring the
PLL multiplier output to 12*4 = 48 MHz. Let's use 12*8 = 96 and then
divide that by two to get to the desired 48 MHz.
This might help to resolve the non-working USB on the qmod so far.
