This provides a more consistent C-level API to raise exceptions, ie moving
away from nlr_raise towards mp_raise_XXX. It also reduces code size by a
small amount on some ports.
If the exception doesn't need printf-style formatting then calling
mp_raise_msg is more efficient. Also shorten exception messages to match
style in core and other ports.
The backlight enable is active low on our board so the driver doesn't like it.
Toggling to GPIO manually for now.
As fixed the improper SPI bus pins definitions and it works!
Signed-off-by: Michael Welling <mwelling@ieee.org>
PacketBuffer facilitates packet oriented BLE protocols such as BLE
MIDI and the Apple Media Service.
This also adds PHY, MTU and connection event extension negotiation
to speed up data transfer when possible.
disable only turns off ENABLE but doesn't set the init tracking that
nrfx uses. uninit hangs if ENABLE is off and is called because it
waits forever for TX to stop.
For the 3 ports that already make use of this feature (stm32, nrf and
teensy) this doesn't make any difference, it just allows to disable it from
now on.
For other ports that use pyexec, this decreases code size because the debug
printing code is dead (it can't be enabled) but the compiler can't deduce
that, so code is still emitted.
.. a requirement that oofatfs needs to be taught to respect.
This problem can be demonstrated with the following snippet, except
that the related file ("test.bin") must also be contiguous on the
filesystem. You can ensure this by reformatting your device's filesystem
before testing, then copying any single file bigger than 4kB to test.bin.
f = open("test.bin", "rb")
f.seek(2048)
b = bytearray(2048)
v = memoryview(b)
f.readinto(v[909:])
Closes: #2332
The "spacing" of "buffer structure" is confusing, use the "channel count"
instead.
Testing performed on nrf52840 feather:
Play stereo and mono, 8- and 16-bit, 8kHz RawSamples representing 333.33Hz
square waves.
Use both mono and stereo PWMAudioOut instances.
Scope the RC-filtered signal and use the scope's frequency
measurement function, verify the frequency is 333 or 334Hz in all tested
cases.
In the "stereo output" cases, verify both the L and R channels. Verify
the output amplitude is the same in both channels.
In the "stereo output" cases, run a second test where the L channel's
amplitude is attenuated 50%. Verify the output amplitude is correct
in each channel.
The sample width register was never set, so all samples were played
as though they were 16 bit.
After this change, 8-bit samples no longer produce audio on the MAX 98357A
BOB, because only 16-, 24-, and 32-bit samples are supported by the
hardware. This will be addressed by a future change to pad samples to
16 bits; see #2323 and the 98357A datasheet page 6.
The meaning of the "single channel" parameter is not well-documented,
but in fact it seems that "true" must be passed or else the returned
channel_count is always 1. This caused stereo samples to be played
incorrectly.
This caused two problems when playing unsigned samples:
* When an even number of samples were present, it "worked" but only
every other sample was copied into the output, changing the waveform
* When an odd number of samples were present, the copy continued beyond
the end of the buffers and caused a hard fault
If we put no samples into the buffer, then there is no last
sample to fill out hold_value with. (and, in fact, the expression such
as *(uint32_t*)(buffer-4) is outside an allocated region)
Detect this condition, and leave the prior value in place.
This improves clicks heard when pausing and resuming a waveform.
This code is shared by most parts, except where not all the #ifdefs
inside the tick function were present in all ports. This mostly would
have broken gamepad tick support on non-samd ports.
The "ms32" and "ms64" variants of the tick functions are introduced
because there is no 64-bit atomic read. Disabling interrupts avoids
a low probability bug where milliseconds could be off by ~49.5 days
once every ~49.5 days (2^32 ms).
Avoiding disabling interrupts when only the low 32 bits are needed is a minor
optimization.
Testing performed: on metro m4 express, USB still works and
time.monotonic_ns() still counts up
This commit removes the Makefile-level MICROPY_FATFS config and moves the
MICROPY_VFS_FAT config to the Makefile level to replace it. It also moves
the include of the oofatfs source files in the build from each port to a
central place in extmod/extmod.mk.
For a port to enabled VFS FAT support it should now set MICROPY_VFS_FAT=1
at the level of the Makefile. This will include the relevant oofatfs files
in the build and set MICROPY_VFS_FAT=1 at the C (preprocessor) level.
This allows the board to disable the onboard speaker until explicitly
enabled in user code.
Testing performed on a CPB:
* Touching the AUDIO pin with a fingertip no longer generates noise/buzz
* Generating a waveform with `simpleio.tone` produces no sound by default
* When the board.SPEAKER_ENABLE is configured as a digital output and
set True, `simpleio.tone` does produce sound
Note that while guides should include information about SPEAKER_ENABLE, it's
possible that some users who omitted it could view this as a breaking change.
They can fix it by simply adding code similar to
speaker_enable = digitalio.DigitalInOut(board.SPEAKER_ENABLE)
speaker_enable.direction = digitalio.Direction.OUTPUT
speaker_enable.value = True
before using the internal speaker.
Closes: #2258
This commit implements automatic module weak links for all built-in
modules, by searching for "ufoo" in the built-in module list if "foo"
cannot be found. This means that all modules named "ufoo" are always
available as "foo". Also, a port can no longer add any other weak links,
which makes strict the definition of a weak link.
It saves some code size (about 100-200 bytes) on ports that previously had
lots of weak links.
Some changes from the previous behaviour:
- It doesn't intern the non-u module names (eg "foo" is not interned),
which saves code size, but will mean that "import foo" creates a new qstr
(namely "foo") in RAM (unless the importing module is frozen).
- help('modules') no longer lists non-u module names, only the u-variants;
this reduces duplication in the help listing.
Weak links are effectively the same as having a set of symbolic links on
the filesystem that is searched last. So an "import foo" will search
built-in modules first, then all paths in sys.path, then weak links last,
importing "ufoo" if it exists. Thus a file called "foo.py" somewhere in
sys.path will still have precedence over the weak link of "foo" to "ufoo".
See issues: #1740, #4449, #5229, #5241.
This PR refines the _bleio API. It was originally motivated by
the addition of a new CircuitPython service that enables reading
and modifying files on the device. Moving the BLE lifecycle outside
of the VM motivated a number of changes to remove heap allocations
in some APIs.
It also motivated unifying connection initiation to the Adapter class
rather than the Central and Peripheral classes which have been removed.
Adapter now handles the GAP portion of BLE including advertising, which
has moved but is largely unchanged, and scanning, which has been enhanced
to return an iterator of filtered results.
Once a connection is created (either by us (aka Central) or a remote
device (aka Peripheral)) it is represented by a new Connection class.
This class knows the current connection state and can discover and
instantiate remote Services along with their Characteristics and
Descriptors.
Relates to #586
.. otherwise, when an AudioPWMOut object was deinitted without being
explicitly stop()ped, it would use up a slot in active_audio[]; the
5th iteration would create a non-working audio object which would just
buzz instead of playing the right thing.
Closes: #2203
This patch add basic building blocks for nrf9P60.
It also includes a secure bootloader which forwards all
possible peripherals that are user selectable to become
non-secure. After configuring Flash, RAM and peripherals
the secure bootloader will jump to the non-secure domain
where MicroPython is placed.
The minimum size of a secure boot has to be a flash
block of 32Kb, hence why the linker scripts are
offsetting the main application this much.
The RAM offset is set to 128K, to allow for later
integration of Nordic Semiconductor's BSD socket
library which reserves the range 0x20010000 - 0x2001FFFF.
Add support for pca10059 with REPL over tinyusb USB CDC.
The board also includes a board specific module that will
recover UICR->REGOUT0 in case this has been erased.
This initial support does not preserve any existing bootloader
on the pca10090 in case this was present, and expects to use all
available flash on the device.
Add nrf-port finyusb driver files. USB CDC can be activated
by board configuration files using the MICROPY_HW_USB_CDC.
Updating BLE driver, Makefile, nrfx-glue and main.c to plug
in the tinyusb stack.
The the nrfx driver is aware of chip specific registers, while
the raw HAL abstraction is not. This driver enables use of NVMC
in non-secure domain for nrf9160.
This patch moves the check for MICROPY_PY_MACHINE_TEMP to come
before the inclusion of nrf_temp.h. The nrf_temp.h depends on
the NRF_TEMP_Type which might not be defined for all nRF devices.
@ladyada says:
"having this be adjustable (reference) would be ideal cause you can get
absolute voltages but for now, VCC/4 + 4x matches every other chip :)"
... and indeed doing it this way happens to give a much more steady
reading when using a VCC-referenced resistance, and so many of the simple
things you'd wire up are actually VCC-referenced anyway.
.. based on some tasks I found that caused stuttering:
# Test SD and printing
while True: os.listdir('.')
# Test bulk I/O
while True: len(open('somefile.wav', 'rb').read())
Each of these tasks *WAS* worse and I am improving them in a separate
PR by adding RUN_BACKGROUND_TASKS to them.
This enables the highest level of debug symbols, and all optimizations
except lto that do NOT interfere with debugging, in the view of the gcc
maintainers.
Testing performed: I used a Particle Xenon with a HDA1334 I2S DAC.
I played a variety of mono 16-bit samples at 11025 and 22050Hz nominal
bit rates. With this setup, all the 11025Hz samples sound good.
I tested play, pause, and loop functionality.
During some runs with 22050Hz samples, there were glitches. However,
these may have only occurred during runs where I had set breakpoints
and watchpoints in gdb.
I also tested with a MAX98357A I2S amplifier. On this device, everything
sounded "scratchy". I was powering it from 5V and the 5V rail seemed
steady, so I don't have an explanation for this. However, I haven't
tried it with a SAMD board.
It was previously not taking into account that the list of pins was sparse,
so using the wrong index. The boards/X/pins.csv was generating the wrong
data for machine.Pin.board.
As part of this fix rename the variables to make it more clear what the
list contains (only board pins).
mp_compile no longer takes an emit_opt argument, rather this setting is now
provided by the global default_emit_opt variable.
Now, when -X emit=native is passed as a command-line option, the emitter
will be set for all compiled modules (included imports), not just the
top-level script.
In the future there could be a way to also set this variable from a script.
Fixes issue #4267.
So far, this supports only 16kHz and 16-bit samples with a fixed gain.
This is enough to support the basic functionality of e.g., sensing
ambient audio levels.
The original formulation was because I saw the need to avoid a transition
from playing to stopped exactly when a resume was taking place. However,
@tannewt was concerned about this pause causing trouble, because it could
be relatively lengthy (several ms even in a typical case).
After reflection, I've convinced myself that updating the registers
in this order in resume avoids a window where a "stopped" event can
be missed as long as the shortcut is updated first.
Testing re-performed: pause/resume testing of looped RawSample and
WaveFile audio sources.
Testing performed: installed freshly built .uf2 on a Particle Xenon.
Checked that circuitpython still starts.
Checked that the size of all .uf2 files for nrf builds are plausible.
Aside from memory savings, the performance of Python code (pystone)
increased by about +14%.
However, this adds about 12-16 seconds to each nrf build.
Timings & Sizes (build system: i5-3320M, -j5 parallelism on 4 threads):
Before:
$ make -j5 BOARD=particle_xenon
765004 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232076 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
68.54user 11.83system 0:34.34elapsed 234%CPU
pystones before: 570
After:
$ make -j5 BOARD=particle_xenon
804284 bytes free in flash out of 1048576 bytes ( 1024.0 kb ).
232072 bytes free in ram for stack out of 245760 bytes ( 240.0 kb ).
71.06user 11.77system 0:46.91elapsed 176%CPU
pystones after: 650
Timings on travis:
Before:
Build feather_nrf52840_express for pl took 55.79s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 3.18s and succeeded
After:
Build feather_nrf52840_express for pl took 62.72s and succeeded
Build feather_nrf52840_express for zh_Latn_pinyin took 19.10s
Closes: #1396
This implements AudioOut, with known caveats:
* pause/resume are not yet implemented (this is just a bug)
* at best, the sample fidelity is 8 bits (this is a hardware limitation)
Testing performed:
My test system is a Particle Xenon with a PAM8302 op-amp
https://www.adafruit.com/product/2130 and 8-ohm speaker. There's no
analog filtering between the Xenon's PWM pin and the "A+" input of
the amplifier; the "A-" pin is disconnected. It is powered from
VUSB.
I used pin D4, which is *NOT* listed as a low-speed-only pin, but
the code does NOT switch the pin to high drive. This is related to
an open issue for general inability to set drive level for pins
being used by a "special function" on nrf:
https://github.com/adafruit/circuitpython/issues/1270
Nothing about the code I've written should limit the usable pins.
All samples I played were 16-bit, generally monophonic at 11025Hz
and 22050Hz from the Debian LibreOffice package.
This also improves Palette so it stores the original RGB888 colors.
Lastly, it adds I2CDisplay as a display bus to talk over I2C. Particularly
useful for the SSD1306.
Fixes#1828. Fixes#1956
Change static LED functions to lowercase names, and trim down source code
lines for variants of MICROPY_HW_LED_COUNT. Also rename configuration for
MICROPY_HW_LEDx_LEVEL to MICROPY_HW_LEDx_PULLUP to align with global PULLUP
configuration.
- IBK-BLYST-NANO: Breakout board
- IDK-BLYST-NANO: DevKit board with builtin IDAP-M CMSIS-DAP Debug JTAG,
RGB led
- BLUEIO-TAG-EVIM: Sensor tag board (environmental sensor
(T, H, P, Air quality) + 9 axis motion sensor)
Also, the LED module has been updated to support individual base level
configuration of each LED. If set, this will be used instead of the
common configuration, MICROPY_HW_LED_PULLUP. The new configuration,
MICROPY_HW_LEDX_LEVEL, where X is the LED number can be used to set
the base level of the specific LED.
The stm32 and nrf ports already had the behaviour that they would first
check if the script exists before executing it, and this patch makes all
other ports work the same way. This helps when developing apps because
it's hard to tell (when unconditionally trying to execute the scripts) if
the resulting OSError at boot up comes from missing boot.py or main.py, or
from some other error. And it's not really an error if these scripts don't
exist.
Adding section about on how to disable use of the linker flag
-flto, by setting the LTO=0 argument to Make. Also, added a
note on recommended toolchains to use that works well with
LTO enabled.
Removing linker script for nrf52840 s140 v6.0.0 as pca10056
target board now points to the new v6.1.1. Also, removing the
entry from the download_ble_stack.sh script.
Removing linker script for nrf52832 s132 v6.0.0 as all target
boards now points to the new v6.1.1. Also, removing the entry
from the download_ble_stack.sh script.
This patch makes sure that the char_data.props is first
assigned a value before other flags are OR'd in.
Resolves compilation warning on possible unitialized variable.
This patch makes sure that advertisment data is located in
persistent static RAM memory throughout the advertisment.
Also, setting m_adv_handle to predifined
BLE_GAP_ADV_SET_HANDLE_NOT_SET value to indicate first time
usage of the handle. Upon first advertisment configuration
this will be populated with a handle value returned by the
stack (s132/s140).
After new layout of nordicsemi.com the direct links to
command line tools (nrfjprog) has changed to become dynamic.
This patch removes the old direct links to each specific OS
variant and is replaced with one single link to the download
landing page instead.
This changes a number of things in displayio:
* Introduces BuiltinFont and Glyph so the built in font can be used by libraries. For boards with
a font it is available as board.TERMINAL_FONT. Fixes#1172
* Remove _load_row from Bitmap in favor of bitmap[] access. Index can be x/y tuple or overall index. Fixes#1191
* Add width and height properties to Bitmap.
* Add insert and [] access to Group. Fixes#1518
* Add index param to pop on Group.
* Terminal no longer takes unicode character info. It takes a BuiltinFont instead.
* Fix Terminal's handling of [###D vt100 commands used when up arrowing into repl history.
* Add x and y positions to Group plus scale as well.
* Add bitmap accessor for BuiltinFont
Don't exclude the Timer instance 1 entry from machine_timer_obj[] when
using soft PWM. The usage is already checked when creating the Timer,
so just create an empty entry.
If needed these parameters can be added back and made functional one at a
time. It's better to explicitly not support them than to silently allow
but ignore them.
Due to new webpages at nordicsemi.com, the download links
for Bluetooth LE stacks were broken.
This patch updates the links to new locations for the current
targets.
It wasn't being run due to a rework done only on the atmel-samd port.
The rework itself isn't needed now that the heap check triggers safe
mode instead of throwing a Python exception. So, I've removed the
rework.
This creates a common safe mode mechanic that ports can share.
As a result, the nRF52 now has safe mode support as well.
The common safe mode adds a 700ms delay at startup where a reset
during that window will cause a reset into safe mode. This window
is designated by a yellow status pixel and flashing the single led
three times.
A couple NeoPixel fixes are included for the nRF52 as well.
Fixes#1034. Fixes#990. Fixes#615.
We were writing with quad page program including the address (0x38)
which is unsupported by the GD25Q16C but it is supported by the
flash on the DK. So, we use the single address, quad data command
(0x32).
This started while adding USB MIDI support (and descriptor support is
in this change.) When seeing that I'd have to implement the MIDI class
logic twice, once for atmel-samd and once for nrf, I decided to refactor
the USB stack so its shared across ports. This has led to a number of
changes that remove items from the ports folder and move them into
supervisor.
Furthermore, we had external SPI flash support for nrf pending so I
factored out the connection between the usb stack and the flash API as
well. This PR also includes the QSPI support for nRF.
Because of the very specific way nRF requires service registration
(characteristics can be added only to last added service), we would
have to write the Python code in a specific way. With this patch the
user has more freedom.
This was the last class from ubluepy and so that module is now gone.
The Device class offers both Peripheral and Central functionality.
See the inline docs for more info.
For s132 and s140, GAP_ADV_MAX_SIZE was currently set to
BLE_GATT_ATT_MTU_DEFAULT, which is 23. The correct value
should have been 31, but there are no define for this in
the s132/s140 header files as for s110.
Updating define in ble_drv.c to the correct value of 31.
The NRF52 define only covers nrf52832, so update the define checks
to use NRF52_SERIES to cover both nrf52832 and nrf52840.
Fixed machine_hard_pwm_instances table in modules/machine/pwm.c
This enables PWM(0) to PWM(3), RTCounter(2), Timer(3) and Timer(4),
in addition to NFC reset cause, on nrf52840.
Adding MICROPY_FATFS as makefile flag in order to explicitly
include oofatfs files to be compiled into the build.
The flag is set to 0 by default. Must be set in addition to
MICROPY_VFS and MICROPY_VFS_FAT in mpconfigport.h.
Temporarly solving the issue of
"differ from the size of original declaration [-Werror=lto-type-mismatch]
until linker is fixed in upcomming release of gcc.
Bug is reported by others, and will be fixed in next version of arm-gcc.
However, this patch makes it possible to use modmusic and modimage
with current compilers.
Alternativly, the code can be compiled with LTO=0, but uses valuable 9K
more on this already squeezed target (microbit).
Support added for s132/s140 v6 in linker scripts and boards.
Support removed for s132 v2/3/5.
Download script updated to fetch new stacks and removed the
non-supported ones.
ble_drv.c updated to only handle s110 v8, and s132/s140 v6.
ubluepy updated to continue scanning after each individual scan
report reported to the module to keep old behaviour of the
Scanner class.
This patch generalize the feather52 target to be a board without
an in-built Bluetooth stack or bootloader giving all flash memory to
micropython code.
This way the feather52 target can run any supported Bluetooth LE
stack the port supports for other nrf52832 targets. Hence, this
make Makefiles/linker scripts and BLE driver support easier
to maintain in the future.
Current adoption on top of nrfx only reads the GPIO->IN register.
In order to read back an output state, nrf_gpio_pin_out_read has
to be called.
This patch concatinate the two read functions such that, if
either IN or OUT register has a value 1 it will return this,
else 0.
Updating lib/nrfx submodule to latest version of master to get
the new GPIO API to read pin direction.
(nrfx: d37b16f2b894b0928395f6f56ca741287a31a244)
Cleaning up use of "pyb" module.
Moving the file to a new folder and updating the
makefile accordingly. New module created called
"board" to take over the functionality of the legacy
"pyb" module.
Updating outdated documentation referring to pyb.Pin,
to now point to machine.Pin.
As EasyDMA variant of SPI(M) might clock out an additional byte
in single byte transactions this patch moves the nrf52832 to
use SPI and not SPIM to get more stable data transactions.
Ref: nrf52832 rev2 errata v1.1, suggested workaround is:
"Use the SPI module (deprecated but still available) or
use the following workaround with SPIM ..."
Current nrfx SPIM driver does not contain this workaround,
and in the meanwhile moving back to SPI fixes the issue.
Also, tabbing the nrfx_config.h a bit to make it more readable.
This patch moves the check of SPI configuration before
including any SPI header files. As targets might disable SPI
support, current code ends up in including SPIM if not SPI
is configured. Hence, this is why the check whether the module is
enabled should be done before including headers.
dfu-gen .PHONY target is run unconditionally as first build
target when included, and might fail if the hex file is not
yet generated.
To prevent this, the dfu-gen and dfu-flash targets are moved
to the main Makefile and only exposed if feather52 is the
defined BOARD.
Update configuration define from
MICROPY_HW_HAS_BUILTIN_FLASH to MICROPY_MBFS.
MICROPY_MBFS will enable the builtin flash as
part of enabling the micro:bit FS.
Clang understands only -fshort-enums, not --short-enums. As
--short-enums isn't even mentioned in the gcc man page, I think this
alias exists more for backwards compatibility.
Removing unused nrf52832_512k_64k_s132_5.0.0.ld.
Adding new linker script s132_5.0.0 following new
linker script scheme.
Updating ble_drv.c to handle de-increment of
outstanding tx packets on hvx for s132 v5.
After nrfx 1.0.0 a new macro was introduced to do a common
hardware timeout. The macro function triggers a counter of
retries or a timeout in us. However, in many cases, like in
nrfx_adc.c the timeout value is set to 0, leading to a infinite
loop in mp_hal_delay_us. This patch prevents this from happening.
Path of error:
nrfx_adc.c -> NRFX_WAIT_FOR -> NRFX_DELAY_US -> mp_hal_delay_us.
This patch also opens up for all arguments to be set as positional
arguments such that an external user of the make_new function can set
provide all parameters as positional arguments.
machine/i2c already uses mp_hal_get_pin_obj which
points to pin_find function in order to locate correct
pin object to use.
The pin_find function was recently updated to also
being able to locate pins based on an integer value,
such that pin number can be used as argument to object
constructors.
This patch modfies and uniforms pin object lookup for
SPI, music and pwm.
Renaming config for enabling random module with hw
random number generator from MICROPY_PY_HW_RNG to
MICROPY_PY_RANDOM_HW_RNG to indicate which module it
is configuring.
Also, disabling the config by default in mpconfigport.h.
Adding the enable of RNG in all board configs.
Moving ifdef in modrandom, which test for the config being
set, earlier in the code. This is to prevent un-necessary
includes if not needed.
Increase the maximum number of queued notifications from 1 to 6. This
massively speeds up the NUS console - especially when printing large
amounts of text. The reason is that multiple transfers can be done in a
single connection event, in ideal cases 6 at a time.
This patch moves all nrf52 targets to use SPIM backend
for SPI which features EasyDMA. The main benefit of doing
this is to utilize the SPIM3 on nrf52840 which is
EasyDMA only peripheral.
This patch ads irq method to the pin object. Handlers
registered in the irq method will be kept as part of the
ROOT_POINTERS.
In order to resolve which pin object is the root of the
IRQ, the pin_find has been extended to also be able to
search up Pin objects based on mp_int_t pin number.
This also implies that the Pin.new API is now also supporting
creation of Pin objects based on the integer value of the
pin instead of old style mandating string name of the Pin.
All boards have been updated to use real pin number from
0-48 instead of pin_Pxx for UART/SPI and music module pins.
UART/SPI/modmusic has also been updated to use pin number
provided directly or look up the Pin object based on the
integer value of the pin (modmusic).
Pin generation has been updated to create a list of pins, where
the board/cpu dicts are now refering to an index in this list
instead of having one const declaration for each pin. This new
const table makes it possible to iterate through all pins generated
in order to locate the correct Pin object.
In order to be able to support GPIO1 port on nrf52840
the port has been removed from the Pin object.
All pins on port1 will now be incrementally on top of
the pin numbers for gpio0. Hence, Pin 1.00 will become
P32, and Pin 1.15 will become P47.
The modification is done to address the new gpio HAL
interface in nrfx, which resolves the port to be
configured base on a multiple of 32.
The patch also affects the existing devices which does
not have a second GPIO port in the way that the
port indication A and B is removed from Pin generation.
This means that the port which was earlier addressed
as PA0 is now P0, and PA31 is P31.
Also, this patch removes the gpio member which earlier
pointed to the perihperal GPIO base address. This is not
needed anymore, hence removed.
With all the variation in chips and boards it's tedious to copy and
redefine linker scripts for every option. Making linker scripts more
modular also opens up more possibilities, like enabling/disabling the
flash file system from the Makefile - or even defining it's size from a
Makefile argument (FS_SIZE=12 for a 12kB filesystem if tight on space).
