From a17229a4c16e62269034a4dcf45c4fc36d19c96f Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Tue, 26 Jul 2016 10:58:33 -0400 Subject: [PATCH] docs: ARM updates for Code_Overview.md Some details on the code flow and organization have changed since support for ARM processors was added. Update Code_Overview.md accordingly. Signed-off-by: Kevin O'Connor --- docs/Code_Overview.md | 57 ++++++++++++++++++++++++++----------------- 1 file changed, 35 insertions(+), 22 deletions(-) diff --git a/docs/Code_Overview.md b/docs/Code_Overview.md index 34550e25..1522c60b 100644 --- a/docs/Code_Overview.md +++ b/docs/Code_Overview.md @@ -6,13 +6,22 @@ Directory Layout The **src/** directory contains the C source for the micro-controller code. The **src/avr/** directory contains specific code for Atmel -ATmega micro-controllers. The **src/simulator/** contains code stubs -that allow the micro-controller to be test compiled on other -architectures. +ATmega micro-controllers. The **src/sam3x8e/** directory contains code +specific to the Arduino Due style ARM micro-controllers. The +**src/simulator/** contains code stubs that allow the micro-controller +to be test compiled on other architectures. The **src/generic/** +directory contains helper code that may be useful across different +host architectures. The build arranges for includes of +"board/somefile.h" to first look in the current architecture directory +(eg, src/avr/somefile.h) and then in the generic directory (eg, +src/generic/somefile.h). The **klippy/** directory contains the C and Python source for the host part of the firmware. +The **lib/** directory contains external 3rd-party library code that +is necessary to build some targets. + The **config/** directory contains example printer configuration files. @@ -21,16 +30,18 @@ compiling the micro-controller code. During compilation, the build may create an **out/** directory. This contains temporary build time objects. The final micro-controller -object that is built is in **out/klipper.elf.hex** +object that is built is **out/klipper.elf.hex** on AVR and +**out/klipper.bin** on ARM. Micro-controller code flow ========================== -Execution of the micro-controller code starts in **src/avr/main.c** -which calls sched_main() located in **src/sched.c**. The sched_main() -code starts by running all functions that have been tagged with the -DECL_INIT() macro. It then goes on to repeatedly run all functions -tagged with the DECL_TASK() macro. +Execution of the micro-controller code starts in architecture specific +code (eg, **src/avr/main.c**) which ultimately calls sched_main() +located in **src/sched.c**. The sched_main() code starts by running +all functions that have been tagged with the DECL_INIT() macro. It +then goes on to repeatedly run all functions tagged with the +DECL_TASK() macro. One of the main task functions is command_task() located in **src/command.c**. This function processes incoming serial commands @@ -46,12 +57,13 @@ times by scheduling timers. Timer functions are scheduled by calling sched_timer() (located in **src/sched.c**). The scheduler code will arrange for the given function to be called at the requested clock time. Timer interrupts -are initially handled in an interrupt handler in **src/avr/timer.c**, -but this just calls sched_timer_kick() located in **src/sched.c**. The -timer interrupt leads to execution of schedule timer functions. Timer -functions always run with interrupts disabled. The timer functions -should always complete within a few micro-seconds. At completion of -the timer event, the function may choose to reschedule itself. +are initially handled in an architecture specific interrupt handler +(eg, **src/avr/timer.c**), but this just calls sched_timer_kick() +located in **src/sched.c**. The timer interrupt leads to execution of +schedule timer functions. Timer functions always run with interrupts +disabled. The timer functions should always complete within a few +micro-seconds. At completion of the timer event, the function may +choose to reschedule itself. In the event an error is detected the code can invoke shutdown() (a macro which calls sched_shutdown() located in **src/sched.c**). @@ -62,12 +74,12 @@ interrupts disabled. Much of the functionality of the micro-controller involves working with General-Purpose Input/Output pins (GPIO). In order to abstract the low-level architecture specific code from the high-level task -code, all GPIO events are implemented via wrappers. These wrappers are -located in **src/avr/gpio.c**. The code is compiled with gcc's "-flto --fwhole-program" optimization which does an excellent job of inlining -functions across compilation units, so most of these tiny gpio -functions are inlined into their callers, and there is no run-time -cost to using them. +code, all GPIO events are implemented in architectures specific +wrappers (eg, **src/avr/gpio.c**). The code is compiled with gcc's +"-flto -fwhole-program" optimization which does an excellent job of +inlining functions across compilation units, so most of these tiny +gpio functions are inlined into their callers, and there is no +run-time cost to using them. Klippy code overview ==================== @@ -90,4 +102,5 @@ There are three threads in the Klippy host code. The main thread handles incoming gcode commands. A second thread (which resides entirely in the **klippy/serialqueue.c** C code) handles low-level IO with the serial port. The third thread is used to process response -messages from the micro-controller in the Python code. +messages from the micro-controller in the Python code (see +**klippy/serialhdl.py**).