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/* OpenPC TC (Timer / Clock) support code
* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This idea of this code is to feed the 13.56MHz carrier clock of RC632
* into TCLK1, which is routed to XC1. Then configure TC0 to divide this
* clock by a configurable divider.
*
*/
#include <lib_AT91SAM7.h>
#include <AT91SAM7.h>
#include "dbgu.h"
#include "openpicc.h"
#include "tc_cdiv.h"
#include "led.h"
AT91PS_TCB tcb = AT91C_BASE_TCB;
/* set carrier divider to a specific */
void __ramfunc tc_cdiv_set_divider(u_int16_t div)
{
tcb->TCB_TC0.TC_RC = div;
/* set to 50% duty cycle */
tcb->TCB_TC0.TC_RA = 1;
tcb->TCB_TC0.TC_RB = 1 + (div >> 1);
/* We must reset CV to zero when it was greater than RC.
* In order to not lose phase information when doing that we'll busy wait till CV is
* zero modulo the new RC.*/
/*tc_cdiv_phase_add(tcb->TCB_TC0.TC_RC-(tcb->TCB_TC0.TC_CV%tcb->TCB_TC0.TC_RC));*/
if(tcb->TCB_TC0.TC_CV > div) {
while(tcb->TCB_TC0.TC_CV % div != 0);
tcb->TCB_TC0.TC_CCR = AT91C_TC_SWTRG;
}
}
void __ramfunc tc_cdiv_phase_add(int16_t inc)
{
tcb->TCB_TC0.TC_RA = (tcb->TCB_TC0.TC_RA + inc) % tcb->TCB_TC0.TC_RC;
tcb->TCB_TC0.TC_RB = (tcb->TCB_TC0.TC_RB + inc) % tcb->TCB_TC0.TC_RC;
/* FIXME: can this be done more elegantly? */
if (tcb->TCB_TC0.TC_RA == 0) {
tcb->TCB_TC0.TC_RA += 1;
tcb->TCB_TC0.TC_RB += 1;
}
}
void tc_cdiv_init(void)
{
/* Cfg PA28(TCLK1), PA0(TIOA0), PA1(TIOB0), PA20(TCLK2) as Periph B */
AT91F_PIO_CfgPeriph(AT91C_BASE_PIOA, 0,
OPENPICC_PIO_CARRIER_IN |
OPENPICC_PIO_CARRIER_DIV_OUT |
OPENPICC_PIO_CDIV_HELP_OUT |
OPENPICC_PIO_CDIV_HELP_IN);
AT91F_PMC_EnablePeriphClock(AT91C_BASE_PMC,
((unsigned int) 1 << AT91C_ID_TC0));
/* Enable Clock for TC0 */
tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKEN;
/* Connect TCLK1 to XC1, TCLK2 to XC2 */
tcb->TCB_BMR &= ~(AT91C_TCB_TC1XC1S | AT91C_TCB_TC2XC2S);
tcb->TCB_BMR |= (AT91C_TCB_TC1XC1S_TCLK1 | AT91C_TCB_TC2XC2S_TCLK2);
/* Clock XC1, Wave mode, Reset on RC comp
* TIOA0 on RA comp = set, * TIOA0 on RC comp = clear,
* TIOB0 on EEVT = set, TIOB0 on RB comp = clear,
* EEVT = XC2 (TIOA0) */
tcb->TCB_TC0.TC_CMR = AT91C_TC_CLKS_XC1 | AT91C_TC_WAVE |
AT91C_TC_WAVESEL_UP_AUTO |
AT91C_TC_ACPA_SET | AT91C_TC_ACPC_CLEAR |
AT91C_TC_BEEVT_SET | AT91C_TC_BCPB_CLEAR |
AT91C_TC_EEVT_XC2 | AT91C_TC_ETRGEDG_RISING |
AT91C_TC_BSWTRG_CLEAR | AT91C_TC_ASWTRG_CLEAR;
tc_cdiv_set_divider(128);
/* Reset to start timers */
tcb->TCB_BCR = 1;
}
void tc_cdiv_print(void)
{
DEBUGP("TCB_BMR=0x%08x ", tcb->TCB_BMR);
DEBUGP("TC0_CV=0x%08x ", tcb->TCB_TC0.TC_CV);
DEBUGP("TC0_CMR=0x%08x ", tcb->TCB_TC0.TC_CMR);
DEBUGPCR("TC0_SR=0x%08x", tcb->TCB_TC0.TC_SR);
DEBUGPCR("TC0_RA=0x%04x, TC0_RB=0x%04x, TC0_RC=0x%04x",
tcb->TCB_TC0.TC_RA, tcb->TCB_TC0.TC_RB, tcb->TCB_TC0.TC_RC);
}
void tc_cdiv_fini(void)
{
tcb->TCB_TC0.TC_CCR = AT91C_TC_CLKDIS;
AT91F_PMC_DisablePeriphClock(AT91C_BASE_PMC,
((unsigned int) 1 << AT91C_ID_TC0));
}
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