1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
|
/* 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
#ifdef OPENPICC_USE_CLOCK_GATING
/* Don't spin if FRAME_BURST is clear, the clock is stopped in this case */
&& !(!AT91F_PIO_IsInputSet(AT91C_BASE_PIOA, OPENPICC_PIO_FRAME_BURST))
#endif
) {
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_reset(void)
{
/* Reset to start timers */
tcb->TCB_BCR = 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
#ifdef OPENPICC_USE_CLOCK_GATING
| OPENPICC_PIO_FRAME_BURST
#endif
);
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);
#ifdef OPENPICC_USE_CLOCK_GATING
/* Connect TCLK0 to XC0 */
tcb->TCB_BMR &= ~(AT91C_TCB_TC0XC0S);
tcb->TCB_BMR |= (AT91C_TCB_TC0XC0S_TCLK0);
#endif
/* 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)
* if OPENPICC_MODIFIED_BOARD: BURST on XC0 */
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
#ifdef OPENPICC_USE_CLOCK_GATING
| AT91C_TC_BURST_XC0
#endif
;
tc_cdiv_set_divider(128);
tc_cdiv_reset();
}
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));
}
|
