Thanks to Kyle Lemons for the inspiration and original design. The
implementation in this commit is very different however, building on top
of the software vectoring needed in RISC-V. The result is a flexible
interrupt handler that does not take up any RAM for configuration.
With this change, it's no longer necessary to set a specific pin mode:
it will get autodetected in the Configure() call.
Tested on an ItsyBitsy M4 with the mpu6050 example in the drivers repo.
A small footnote in the datasheet says that interrupt source numbers
correspond to the bit position in INTFLAG. We only need the RXC
interrupt for UART. In other words, ony the _2 interrupts (RXC is in the
2nd bit position) needs to be used for UART to work correctly.
In the future, more interrupts may be needed. They can then be added as
necessary.
I2C uses a hardcoded peripheral instead of referring to a specific
peripheral. In addition to that, it refers to the wrong SERCOM
(SERCOM3), which isn't used on any of the atsamd51 boards for I2C.
This commit lets the compiler know about interrupts and allows
optimizations to be performed based on that: interrupts are eliminated
when they appear to be unused in a program. This is done with a new
pseudo-call (runtime/interrupt.New) that is treated specially by the
compiler.
This greatly cuts down on compile time (by about 5x for small programs)
and also makes the program a whole lot smaller. Overall it cuts down
`make smoke-test` in the drivers repository by half (from 160s to 80s).
This will probably also fix the timeout issue in the Playground:
https://github.com/tinygo-org/playground/issues/7
This commit does the same thing as
https://github.com/tinygo-org/tinygo/pull/597 but for samd51 series
chips. Pin mode and pad numbers are automatically calculated from pin
numbers, returning an error if no valid pinout is possible.
Add a target for the Adafruit Circuit Playground Bluefruit, which is
based on the nRF52840. Adds the necessary code for the machine
package and the json and linker script files in the targets directory.
The machine package code is based on board_circuitplay_express.go,
with modifications made by consulting the wiring diagram on the
adafruit website here:
https://learn.adafruit.com/adafruit-circuit-playground-bluefruit/downloads
Also adds support to the uf2 conversion packacge to set the familyID
field. The Circuit Playground Bluefruit firmware rejects uf2 files
without the family id set to 0xADA52840 (and without the flag specifying
that the family id is present).
UART2 was configured with the wrong SERCOM for the used pins (PB22 and
PB23). However, after changing the SERCOM from 3 to 5 that led to a
conflict with UART1 (used for the on-board WiFi). But the used pins are
also usable from SERCOM 3, so in the end I switched SERCOM5 and SERCOM3
around.
With this change, I was able to get examples/echo working.
These all-caps constants aren't in the Go style, so rename it to
CPUFrequency (which is more aligned with Go style). Additionally, make
it a function so that it is possible to add support for changing the
frequency in the future.
Tested by running `make smoketest`. None of the outputs did change.
This smartwatch doesn't have an on-board debugger, so I picked the one I
was using while getting this smartwatch to run Go programs (the J-Link
EDU Mini).
* machine/samd51: pin method cleanups.
- Use bit-math to select the group in Pin methods.
- Move Pin methods to atsamd51. They are not chip-specific, they apply to the whole atsamd51 family.
- Move the group/pin-id calculation into a helper method.
- Add a Pin.Toggle() method.
Comparing slices against nil currently causes the slice to escape, due
to a limitation in LLVM 8. This leads to lots of unnecessary heap
allocations. With LLVM 9 and some modifications to TinyGo, this should
be fixed. However, this commit is an easy win right now.
Returning an error when both slices are nil is not necessary, when the
check is left out it should just do nothing.
For updating an SPI screen using the st7735 driver, this results in a
~7% performance win.
Instead of configuring machine.I2C0, machine.I2C1, etc. statically,
allow the pins to be set using machine.I2CConfig. This will also
automatically configure the correct pin mode for each pin instead of
having to specify that manually.
The SPI peripheral in the nrf chips support double buffering, which
makes it possible to keep sending continuously. This change introduces
double buffering on the nrf chips, which should improve SPI performance.
Tested on the pca10040 (nrf52832).
Compared to the already supported stm32f103xx "bluepill" board this:
- features 128 KiB flash memory size ("RB" suffix) instead of 64 KiB, see `targets/stm32f103rb.ld`
- has onboard ST-LINK/V2-1 programmer and debugger requiring different OpenOCD configuration file
- uses USART2 connected to ST-LINK/V2-1 debugger as virtual COM port over USB for `putchar()`
- has a user-accessible button besides the reset button
