mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

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targets/TARGET_NUVOTON/TARGET_M451/lp_ticker.c@189:f392fc9709a3, 2019-02-20 (annotated)

Committer:
AnnaBridge
Date:
Wed Feb 20 22:31:08 2019 +0000
Revision:
189:f392fc9709a3
Parent:
188:bcfe06ba3d64 
mbed library release version 165

Who changed what in which revision?

UserRevisionLine numberNew contents of line
<> 149:156823d33999 1 /* mbed Microcontroller Library
<> 149:156823d33999 2 * Copyright (c) 2015-2016 Nuvoton
<> 149:156823d33999 3 *
<> 149:156823d33999 4 * Licensed under the Apache License, Version 2.0 (the "License");
<> 149:156823d33999 5 * you may not use this file except in compliance with the License.
<> 149:156823d33999 6 * You may obtain a copy of the License at
<> 149:156823d33999 7 *
<> 149:156823d33999 8 * http://www.apache.org/licenses/LICENSE-2.0
<> 149:156823d33999 9 *
<> 149:156823d33999 10 * Unless required by applicable law or agreed to in writing, software
<> 149:156823d33999 11 * distributed under the License is distributed on an "AS IS" BASIS,
<> 149:156823d33999 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
<> 149:156823d33999 13 * See the License for the specific language governing permissions and
<> 149:156823d33999 14 * limitations under the License.
<> 149:156823d33999 15 */
AnnaBridge 182:a56a73fd2a6f 16
<> 149:156823d33999 17 #include "lp_ticker_api.h"
<> 149:156823d33999 18
Anna Bridge 186:707f6e361f3e 19 #if DEVICE_LPTICKER
<> 149:156823d33999 20
<> 149:156823d33999 21 #include "sleep_api.h"
AnnaBridge 182:a56a73fd2a6f 22 #include "mbed_assert.h"
<> 149:156823d33999 23 #include "nu_modutil.h"
AnnaBridge 188:bcfe06ba3d64 24 #include "nu_timer.h"
<> 149:156823d33999 25 #include "nu_miscutil.h"
<> 149:156823d33999 26
AnnaBridge 182:a56a73fd2a6f 27 /* Micro seconds per second */
AnnaBridge 182:a56a73fd2a6f 28 #define NU_US_PER_SEC 1000000
AnnaBridge 182:a56a73fd2a6f 29 /* Timer clock per lp_ticker tick */
AnnaBridge 182:a56a73fd2a6f 30 #define NU_TMRCLK_PER_TICK 1
AnnaBridge 182:a56a73fd2a6f 31 /* Timer clock per second */
AnnaBridge 182:a56a73fd2a6f 32 #define NU_TMRCLK_PER_SEC (__LXT)
AnnaBridge 182:a56a73fd2a6f 33 /* Timer max counter bit size */
AnnaBridge 182:a56a73fd2a6f 34 #define NU_TMR_MAXCNT_BITSIZE 24
AnnaBridge 182:a56a73fd2a6f 35 /* Timer max counter */
AnnaBridge 182:a56a73fd2a6f 36 #define NU_TMR_MAXCNT ((1 << NU_TMR_MAXCNT_BITSIZE) - 1)
<> 149:156823d33999 37
AnnaBridge 182:a56a73fd2a6f 38 static void tmr1_vec(void);
<> 149:156823d33999 39
AnnaBridge 182:a56a73fd2a6f 40 /* NOTE: To wake the system from power down mode, timer clock source must be ether LXT or LIRC. */
AnnaBridge 182:a56a73fd2a6f 41 static const struct nu_modinit_s timer1_modinit = {TIMER_1, TMR1_MODULE, CLK_CLKSEL1_TMR1SEL_LXT, 0, TMR1_RST, TMR1_IRQn, (void *) tmr1_vec};
AnnaBridge 182:a56a73fd2a6f 42
AnnaBridge 182:a56a73fd2a6f 43 #define TIMER_MODINIT timer1_modinit
AnnaBridge 182:a56a73fd2a6f 44
AnnaBridge 187:0387e8f68319 45 /* Timer interrupt enable/disable
AnnaBridge 187:0387e8f68319 46 *
AnnaBridge 187:0387e8f68319 47 * Because Timer interrupt enable/disable (TIMER_EnableInt/TIMER_DisableInt) needs wait for lp_ticker,
AnnaBridge 187:0387e8f68319 48 * we call NVIC_DisableIRQ/NVIC_EnableIRQ instead.
AnnaBridge 187:0387e8f68319 49 */
AnnaBridge 187:0387e8f68319 50
AnnaBridge 187:0387e8f68319 51 /* Track ticker status */
AnnaBridge 187:0387e8f68319 52 static volatile uint16_t ticker_inited = 0;
<> 149:156823d33999 53
<> 149:156823d33999 54 #define TMR_CMP_MIN 2
<> 149:156823d33999 55 #define TMR_CMP_MAX 0xFFFFFFu
<> 149:156823d33999 56
AnnaBridge 187:0387e8f68319 57 /* Synchronization issue with LXT/LIRC-clocked Timer
AnnaBridge 187:0387e8f68319 58 *
AnnaBridge 187:0387e8f68319 59 * PCLK : typical HCLK/2
AnnaBridge 187:0387e8f68319 60 * ECLK (engine clock) : LXT/LIRC for Timer used to implement lp_ticker
AnnaBridge 187:0387e8f68319 61 *
AnnaBridge 187:0387e8f68319 62 * When system clock is higher than Timer clock (LXT/LIRC), we need to add delay for ECLK
AnnaBridge 187:0387e8f68319 63 * domain to take effect:
AnnaBridge 187:0387e8f68319 64 * 1. Write : typical 1PCLK + 2ECLK
AnnaBridge 187:0387e8f68319 65 * Read-check doesn't work because it just checks PCLK domain and doesn't check into
AnnaBridge 187:0387e8f68319 66 * ECLK domain.
AnnaBridge 187:0387e8f68319 67 * 2. Clear interrupt flag : typical 2PCLK
AnnaBridge 187:0387e8f68319 68 * It is very rare that we would meet dummy interrupt and get stuck in ISR until
AnnaBridge 187:0387e8f68319 69 * 'clear interrupt flag' takes effect. The issue is ignorable because the pending
AnnaBridge 187:0387e8f68319 70 * time is very short (at most 1 dummy interrupt). We won't take special handling for it.
AnnaBridge 187:0387e8f68319 71 */
AnnaBridge 184:08ed48f1de7f 72
<> 149:156823d33999 73 void lp_ticker_init(void)
<> 149:156823d33999 74 {
AnnaBridge 182:a56a73fd2a6f 75 if (ticker_inited) {
AnnaBridge 187:0387e8f68319 76 /* By HAL spec, ticker_init allows the ticker to keep counting and disables the
AnnaBridge 187:0387e8f68319 77 * ticker interrupt. */
AnnaBridge 187:0387e8f68319 78 lp_ticker_disable_interrupt();
<> 149:156823d33999 79 return;
<> 149:156823d33999 80 }
AnnaBridge 182:a56a73fd2a6f 81 ticker_inited = 1;
<> 149:156823d33999 82
<> 149:156823d33999 83 // Reset module
AnnaBridge 182:a56a73fd2a6f 84 SYS_ResetModule(TIMER_MODINIT.rsetidx);
AnnaBridge 182:a56a73fd2a6f 85
<> 149:156823d33999 86 // Select IP clock source
AnnaBridge 182:a56a73fd2a6f 87 CLK_SetModuleClock(TIMER_MODINIT.clkidx, TIMER_MODINIT.clksrc, TIMER_MODINIT.clkdiv);
AnnaBridge 182:a56a73fd2a6f 88
<> 149:156823d33999 89 // Enable IP clock
AnnaBridge 182:a56a73fd2a6f 90 CLK_EnableModuleClock(TIMER_MODINIT.clkidx);
<> 149:156823d33999 91
AnnaBridge 184:08ed48f1de7f 92 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 184:08ed48f1de7f 93
<> 149:156823d33999 94 // Configure clock
AnnaBridge 184:08ed48f1de7f 95 uint32_t clk_timer = TIMER_GetModuleClock(timer_base);
AnnaBridge 182:a56a73fd2a6f 96 uint32_t prescale_timer = clk_timer / NU_TMRCLK_PER_SEC - 1;
AnnaBridge 182:a56a73fd2a6f 97 MBED_ASSERT((prescale_timer != (uint32_t) -1) && prescale_timer <= 127);
AnnaBridge 182:a56a73fd2a6f 98 MBED_ASSERT((clk_timer % NU_TMRCLK_PER_SEC) == 0);
AnnaBridge 182:a56a73fd2a6f 99 uint32_t cmp_timer = TMR_CMP_MAX;
AnnaBridge 182:a56a73fd2a6f 100 MBED_ASSERT(cmp_timer >= TMR_CMP_MIN && cmp_timer <= TMR_CMP_MAX);
<> 149:156823d33999 101 // Continuous mode
<> 149:156823d33999 102 // NOTE: TIMER_CTL_CNTDATEN_Msk exists in NUC472, but not in M451. In M451, TIMER_CNT is updated continuously by default.
AnnaBridge 184:08ed48f1de7f 103 timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer/* | TIMER_CTL_CNTDATEN_Msk*/;
AnnaBridge 188:bcfe06ba3d64 104 nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 105
AnnaBridge 184:08ed48f1de7f 106 timer_base->CMP = cmp_timer;
AnnaBridge 188:bcfe06ba3d64 107 nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 182:a56a73fd2a6f 108
<> 149:156823d33999 109 // Set vector
AnnaBridge 182:a56a73fd2a6f 110 NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
AnnaBridge 182:a56a73fd2a6f 111
AnnaBridge 187:0387e8f68319 112 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 182:a56a73fd2a6f 113
AnnaBridge 184:08ed48f1de7f 114 TIMER_EnableInt(timer_base);
AnnaBridge 188:bcfe06ba3d64 115 nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 116
AnnaBridge 184:08ed48f1de7f 117 TIMER_EnableWakeup(timer_base);
AnnaBridge 188:bcfe06ba3d64 118 nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 119
AnnaBridge 184:08ed48f1de7f 120 TIMER_Start(timer_base);
AnnaBridge 188:bcfe06ba3d64 121 nu_busy_wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 122
AnnaBridge 184:08ed48f1de7f 123 /* Wait for timer to start counting and raise active flag */
AnnaBridge 184:08ed48f1de7f 124 while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));
<> 149:156823d33999 125 }
<> 149:156823d33999 126
AnnaBridge 187:0387e8f68319 127 void lp_ticker_free(void)
AnnaBridge 187:0387e8f68319 128 {
AnnaBridge 187:0387e8f68319 129 /* Disable interrupt */
AnnaBridge 187:0387e8f68319 130 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 187:0387e8f68319 131
AnnaBridge 187:0387e8f68319 132 /* Disable IP clock */
AnnaBridge 187:0387e8f68319 133 CLK_DisableModuleClock(TIMER_MODINIT.clkidx);
AnnaBridge 187:0387e8f68319 134
AnnaBridge 187:0387e8f68319 135 ticker_inited = 0;
AnnaBridge 187:0387e8f68319 136 }
AnnaBridge 187:0387e8f68319 137
<> 149:156823d33999 138 timestamp_t lp_ticker_read()
AnnaBridge 182:a56a73fd2a6f 139 {
AnnaBridge 182:a56a73fd2a6f 140 if (! ticker_inited) {
<> 149:156823d33999 141 lp_ticker_init();
<> 149:156823d33999 142 }
<> 149:156823d33999 143
AnnaBridge 184:08ed48f1de7f 144 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 182:a56a73fd2a6f 145
AnnaBridge 182:a56a73fd2a6f 146 return (TIMER_GetCounter(timer_base) / NU_TMRCLK_PER_TICK);
<> 149:156823d33999 147 }
<> 149:156823d33999 148
<> 149:156823d33999 149 void lp_ticker_set_interrupt(timestamp_t timestamp)
<> 149:156823d33999 150 {
AnnaBridge 188:bcfe06ba3d64 151 /* Clear any previously pending interrupts */
AnnaBridge 188:bcfe06ba3d64 152 lp_ticker_clear_interrupt();
AnnaBridge 188:bcfe06ba3d64 153 NVIC_ClearPendingIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 188:bcfe06ba3d64 154
AnnaBridge 182:a56a73fd2a6f 155 /* In continuous mode, counter will be reset to zero with the following sequence:
AnnaBridge 182:a56a73fd2a6f 156 * 1. Stop counting
AnnaBridge 182:a56a73fd2a6f 157 * 2. Configure new CMP value
AnnaBridge 182:a56a73fd2a6f 158 * 3. Restart counting
AnnaBridge 182:a56a73fd2a6f 159 *
AnnaBridge 182:a56a73fd2a6f 160 * This behavior is not what we want. To fix it, we could configure new CMP value
AnnaBridge 182:a56a73fd2a6f 161 * without stopping counting first.
AnnaBridge 182:a56a73fd2a6f 162 */
AnnaBridge 184:08ed48f1de7f 163 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 174:b96e65c34a4d 164
AnnaBridge 182:a56a73fd2a6f 165 /* NOTE: Because H/W timer requests min compare value, our implementation would have alarm delay of
AnnaBridge 182:a56a73fd2a6f 166 * (TMR_CMP_MIN - interval_clk) clocks when interval_clk is between [1, TMR_CMP_MIN). */
AnnaBridge 182:a56a73fd2a6f 167 uint32_t cmp_timer = timestamp * NU_TMRCLK_PER_TICK;
AnnaBridge 182:a56a73fd2a6f 168 cmp_timer = NU_CLAMP(cmp_timer, TMR_CMP_MIN, TMR_CMP_MAX);
AnnaBridge 184:08ed48f1de7f 169
AnnaBridge 187:0387e8f68319 170 /* NOTE: Rely on LPTICKER_DELAY_TICKS to be non-blocking. */
AnnaBridge 182:a56a73fd2a6f 171 timer_base->CMP = cmp_timer;
AnnaBridge 187:0387e8f68319 172
AnnaBridge 187:0387e8f68319 173 /* We can call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 174 NVIC_EnableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 175 }
<> 149:156823d33999 176
<> 149:156823d33999 177 void lp_ticker_disable_interrupt(void)
<> 149:156823d33999 178 {
AnnaBridge 187:0387e8f68319 179 /* We cannot call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 180 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 181 }
<> 149:156823d33999 182
<> 149:156823d33999 183 void lp_ticker_clear_interrupt(void)
<> 149:156823d33999 184 {
AnnaBridge 187:0387e8f68319 185 /* To avoid sync issue, we clear TIF/TWKF simultaneously rather than call separate
AnnaBridge 187:0387e8f68319 186 * driver API:
AnnaBridge 187:0387e8f68319 187 *
AnnaBridge 187:0387e8f68319 188 * TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname));
AnnaBridge 187:0387e8f68319 189 * TIMER_ClearWakeupFlag((TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname));
AnnaBridge 187:0387e8f68319 190 */
AnnaBridge 187:0387e8f68319 191 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 187:0387e8f68319 192 timer_base->INTSTS = TIMER_INTSTS_TIF_Msk | TIMER_INTSTS_TWKF_Msk;
<> 149:156823d33999 193 }
<> 149:156823d33999 194
AnnaBridge 182:a56a73fd2a6f 195 void lp_ticker_fire_interrupt(void)
<> 149:156823d33999 196 {
AnnaBridge 182:a56a73fd2a6f 197 // NOTE: This event was in the past. Set the interrupt as pending, but don't process it here.
AnnaBridge 182:a56a73fd2a6f 198 // This prevents a recursive loop under heavy load which can lead to a stack overflow.
AnnaBridge 182:a56a73fd2a6f 199 NVIC_SetPendingIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 187:0387e8f68319 200
AnnaBridge 187:0387e8f68319 201 /* We can call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 202 NVIC_EnableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 203 }
<> 149:156823d33999 204
AnnaBridge 182:a56a73fd2a6f 205 const ticker_info_t* lp_ticker_get_info()
<> 149:156823d33999 206 {
AnnaBridge 182:a56a73fd2a6f 207 static const ticker_info_t info = {
AnnaBridge 182:a56a73fd2a6f 208 NU_TMRCLK_PER_SEC / NU_TMRCLK_PER_TICK,
AnnaBridge 182:a56a73fd2a6f 209 NU_TMR_MAXCNT_BITSIZE
AnnaBridge 182:a56a73fd2a6f 210 };
AnnaBridge 182:a56a73fd2a6f 211 return &info;
AnnaBridge 182:a56a73fd2a6f 212 }
AnnaBridge 182:a56a73fd2a6f 213
AnnaBridge 182:a56a73fd2a6f 214 static void tmr1_vec(void)
AnnaBridge 182:a56a73fd2a6f 215 {
AnnaBridge 187:0387e8f68319 216 lp_ticker_clear_interrupt();
AnnaBridge 184:08ed48f1de7f 217
AnnaBridge 182:a56a73fd2a6f 218 // NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
AnnaBridge 182:a56a73fd2a6f 219 lp_ticker_irq_handler();
<> 149:156823d33999 220 }
AnnaBridge 182:a56a73fd2a6f 221
<> 149:156823d33999 222 #endif