You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
129 lines
3.0 KiB
ArmAsm
129 lines
3.0 KiB
ArmAsm
/*
|
|
* ----------------------------------------------------------------------------
|
|
* "THE BEER-WARE LICENSE" (Revision 42):
|
|
* Joerg Wunsch wrote this file. As long as you retain this notice you
|
|
* can do whatever you want with this stuff. If we meet some day, and you think
|
|
* this stuff is worth it, you can buy me a beer in return. Joerg Wunsch
|
|
* ----------------------------------------------------------------------------
|
|
*
|
|
* Demo combining C and assembly source files.
|
|
*
|
|
* $Id$
|
|
*/
|
|
/*
|
|
* This file contains the interrupt service routine implementations
|
|
* when compiling the project for the ATtiny13 target.
|
|
*/
|
|
|
|
#include <avr/io.h>
|
|
|
|
#include "project.h"
|
|
|
|
#if defined(__AVR_ATtiny13__)
|
|
|
|
/*
|
|
* Timer 0 hit TOP (0xff), i.e. it turns from up-counting
|
|
* into down-counting direction.
|
|
*/
|
|
.global TIM0_COMPA_vect
|
|
TIM0_COMPA_vect:
|
|
in sreg_save, _SFR_IO_ADDR(SREG)
|
|
inc counter_hi
|
|
clr flags
|
|
out _SFR_IO_ADDR(SREG), sreg_save
|
|
reti
|
|
|
|
/*
|
|
* Timer 0 hit BOTTOM (0x00), i.e. it turns from down-counting
|
|
* into up-counting direction.
|
|
*/
|
|
.global TIM0_OVF_vect
|
|
TIM0_OVF_vect:
|
|
in sreg_save, _SFR_IO_ADDR(SREG)
|
|
inc counter_hi
|
|
ser flags
|
|
out _SFR_IO_ADDR(SREG), sreg_save
|
|
reti
|
|
|
|
;;; one 16-bit word to store our rising edge's timestamp
|
|
.lcomm starttime.0, 2
|
|
|
|
.extern pwm_incoming
|
|
.extern intbits
|
|
|
|
.global PCINT0_vect
|
|
PCINT0_vect:
|
|
in sreg_save, _SFR_IO_ADDR(SREG)
|
|
|
|
;; save our working registers
|
|
push r18
|
|
push r19
|
|
push r20
|
|
push r21
|
|
|
|
;; Now that we are ready to fetch the current
|
|
;; value of TCNT0, allow interrupts for a
|
|
;; moment. As the effect of the SEI will be
|
|
;; deferred by one instruction, any possible
|
|
;; rollover of TCNT0 (hitting BOTTOM when
|
|
;; counting down, or MAX when counting up) will
|
|
;; allow the above ISRs to trigger right here,
|
|
;; and update their status, so our combined
|
|
;; 16-bit time from [counter_hi, TCNT0] will
|
|
;; be correct.
|
|
sei
|
|
in r20, _SFR_IO_ADDR(TCNT0)
|
|
cli
|
|
;; Now, make our working copy of the status,
|
|
;; so we can re-enable interrupts again.
|
|
mov r21, counter_hi
|
|
mov r19, flags
|
|
sei
|
|
|
|
;; what direction were we counting?
|
|
sbrs r19, 0
|
|
;; we are down-counting, invert TCNT0
|
|
com r20
|
|
;; at this point, r21:20 has our current
|
|
;; 16-bit time
|
|
|
|
;; now, look which of the edges triggered
|
|
;; our pin-change interrupt
|
|
sbis _SFR_IO_ADDR(PINB), 4
|
|
rjmp 10f
|
|
;; rising edge detected, just record starttime
|
|
sts (starttime.0) + 1, r21
|
|
sts starttime.0, r20
|
|
rjmp 99f ; we are done here
|
|
|
|
;; Falling edge: compute pulse width, store it
|
|
;; into pwm_incoming, disable pin-change
|
|
;; interrupt until the upper layers had a chance
|
|
;; to fetch the result.
|
|
|
|
10: in r18, _SFR_IO_ADDR(GIMSK)
|
|
andi r18, ~(1 << PCIE)
|
|
out _SFR_IO_ADDR(GIMSK), r18
|
|
|
|
;; pwm_incoming = current_time - starttime
|
|
lds r19, (starttime.0) + 1
|
|
lds r18, starttime.0
|
|
sub r20, r18
|
|
sbc r21, r19
|
|
sts (pwm_incoming) + 1, r21
|
|
sts pwm_incoming, r20
|
|
|
|
;; signal upper layer
|
|
lds r18, intbits
|
|
ori r18, 1
|
|
sts intbits, r18
|
|
99:
|
|
pop r21
|
|
pop r20
|
|
pop r19
|
|
pop r18
|
|
|
|
out _SFR_IO_ADDR(SREG), sreg_save
|
|
reti
|
|
#endif /* ATtiny13 */
|