coreyfro
Member
Hey folks,
The reason I got the Maple is because I want a serious piece of hardware to handle interrupts. I have two options, link up lots of micro-controllers, each listening to a device, or get one serious micro-controller. Obviously, I'd prefer the latter.
I would love links to documentation around the interweb, but I'd also like to know more about how to leverage the Maple-IDE and API's to unlock this powerful interrupt controller. Sample code would be great, too.
Thanks!
poslathian
LeafLabs
Were working on getting clean api's together than link to the interrupt (NVIC) system. If youd like to start hacking on it right away, the short answer is thus:
Check the chip documentation here:
http://www.st.com/stonline/products/literature/rm/13902.pdf
and determine how you would like to configure the NVIC and perihperal. This usually comes in two parts, the perihperal itself needs to be configured for interrupts (like the ADC, or the timer, etc), and the NVIC needs to have the particular interrupt channel enabled.
Next you need to overflow the default interrupt handlers (which are weakly declared in the linker script), in your sketch/code. For example, in:
git: libmaple/stm32conf/lanchon-stm32/src/libcs3-lanchon-stm32/lanchon-stm32-vector.S
we see defined the default interrupt handler routines, like "ADC_IRQHandler"
These defaults do nothing, but if you define them in your sketch like:
void ADC_IRQHandler(void) {
// stuff
}
And have the NVIC and ADC configured for it, then that should work for you.
We'll be posting more thorough documentation on interrupts/NVIC as it gets added to libmaple. Ideally we want to turn the process in to something like
Adc.Begin(ptr-to-interrupt-routine,config params);
or something...the design for this is in the works but im out of the loop. We do rely on interrupts in several places in libmaple, to provide interfaces to timers, external interrupts, and the systick - I'll dig up the exact locations in the code so you can see how its done.
jigajigajoo
Member
Is the procedure to setup interrupts on the Maple still valid? I tried to follow the steps... I was trying to get the interrupt from the ADC to work... basically every conversion, the ADC sends an interrupt out to signal a complete conversion.
I first initialized the ADC (initADC()). I then added an interrupt on the nvic, and the peripheral (in my case the ADC) (initInterrupts()), and then tried to overload the interrupt handlerADC_IRQHandler(). I didn't get it to work.... any input would be invaluable.
The full code:
// START CONSTANTS
const uint8 numMics = 6;
volatile int tic = 0;
// sampleRate = number of ADC cycles per read = ADC_SMPR_x + 12.5 =
// samples per cycle at 14 MHz. For ADC_SMPR_1_5, total conversion time = 1 microsec.
const adc_smp_rate sampleRate = ADC_SMPR_28_5;
const int sampleRateInt = 28.5;
// we're using raw adc channels via adcChans instead of micPins
const int micPins[6] = {D15, D16, D17, D18, D19, D20};
// below refers to channels according to ADC docs, and not to pins on maple
// 10-15 correspond to pins D15-D20 on maple
// the order of adcChans decides the order in which the channels are read
// (ie first one = chan0, etc)
const uint8 adcChans[6] = {10, 11, 12, 13, 14, 15};
HardwareTimer timer(1);
// END CONSTANTS
// Analog input pin. You may need to change this number if your board
// can't do analog input on pin 15.
const int analogStartPin = 15;
void setup() {
// Set up board LED to blink, useful for debugging
pinMode(BOARD_LED_PIN, OUTPUT);
// Declare analogInputPin as INPUT_ANALOG:
for(int i = 0; i < numMics; i++)
{
pinMode(micPins[i], INPUT_ANALOG);
}
initADC();
initInterrupts();
}
void initADC() {
// ADC register map
adc_reg_map *regs = ADC1->regs;
// below not needed, maplelib does it for us!
//adc_init(ADC1);
// if adc is on, turn it off so we can change settings
if(regs->CR2 | ADC_CR2_ADON) {
regs->CR2 ^= ADC_CR2_ADON;
}
adc_set_sample_rate(ADC1, sampleRate);
// set number of channels to read
adc_set_reg_seqlen(ADC1, numMics);
// set channel read sequence order (from adcChans)
uint32 channels = 0;
for (int i = 0; i < numMics; i++) {
channels |= (adcChans[i] << (i*4));
}
regs->SQR3 = channels;
// scan mode on
regs->CR1 |= ADC_CR1_SCAN;
// continuous mode on
regs->CR2 |= ADC_CR2_CONT;
// enable end_of_conversion interrupts
regs->CR1 |= ADC_CR1_EOCIE;
// calibrate ADC
adc_calibrate(ADC1);
// turn on ADC
regs->CR2 |= ADC_CR2_ADON;
// start adc read
regs->CR2 |= ADC_CR2_SWSTART;
}
void initInterrupts() {
// enable adc interrupt on the interrupt controller
nvic_globalirq_enable();
nvic_irq_enable(NVIC_ADC_1_2);
//enable adc interrupt on the adc
}
void ADC_IRQHandler(void) {
SerialUSB.print('x');
tic++;
if(tic == 60)
{
tic = 0;
toggleLED();
}
}
void loop() {
// use interrupts!
}
mbolivar
LeafLabs
Is the procedure to setup interrupts on the Maple still valid? I tried to follow the steps... I was trying to get the interrupt from the ADC to work... basically every conversion, the ADC sends an interrupt out to signal a complete conversion.
nope. libmaple has been refactored significantly since the time of those posts. the names of the weakly-defined IRQ handlers are still given in libmaple's /support/ld/names.inc, but the names have all changed:
https://github.com/leaflabs/libmaple/blob/0.0.11/support/ld/names.inc
the IRQ handler for ADC1 and ADC2 isn't currently defined by libmaple, so just defining your own (and calling it "__irq_adc") should do the trick.
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