mbed official / mbed-dev

mbed library sources. Supersedes mbed-src.

Dependents:   Nucleo_Hello_Encoder BLE_iBeaconScan AM1805_DEMO DISCO-F429ZI_ExportTemplate1 ... more

targets/TARGET_NUVOTON/TARGET_NUC472/lp_ticker.c@187:0387e8f68319, 2018-09-06 (annotated)

Committer:
AnnaBridge
Date:
Thu Sep 06 13:40:20 2018 +0100
Revision:
187:0387e8f68319
Parent:
186:707f6e361f3e
Child:
188:bcfe06ba3d64
mbed-dev library. Release version 163

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_wait_api.h"
AnnaBridge 182:a56a73fd2a6f 23 #include "mbed_assert.h"
<> 149:156823d33999 24 #include "nu_modutil.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();
AnnaBridge 187:0387e8f68319 79 lp_ticker_clear_interrupt();
AnnaBridge 187:0387e8f68319 80 NVIC_ClearPendingIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 81 return;
<> 149:156823d33999 82 }
AnnaBridge 182:a56a73fd2a6f 83 ticker_inited = 1;
<> 149:156823d33999 84
<> 149:156823d33999 85 // Reset module
AnnaBridge 182:a56a73fd2a6f 86 SYS_ResetModule(TIMER_MODINIT.rsetidx);
AnnaBridge 182:a56a73fd2a6f 87
<> 149:156823d33999 88 // Select IP clock source
AnnaBridge 182:a56a73fd2a6f 89 CLK_SetModuleClock(TIMER_MODINIT.clkidx, TIMER_MODINIT.clksrc, TIMER_MODINIT.clkdiv);
AnnaBridge 182:a56a73fd2a6f 90
<> 149:156823d33999 91 // Enable IP clock
AnnaBridge 182:a56a73fd2a6f 92 CLK_EnableModuleClock(TIMER_MODINIT.clkidx);
<> 149:156823d33999 93
AnnaBridge 184:08ed48f1de7f 94 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 184:08ed48f1de7f 95
<> 149:156823d33999 96 // Configure clock
AnnaBridge 184:08ed48f1de7f 97 uint32_t clk_timer = TIMER_GetModuleClock(timer_base);
AnnaBridge 182:a56a73fd2a6f 98 uint32_t prescale_timer = clk_timer / NU_TMRCLK_PER_SEC - 1;
AnnaBridge 182:a56a73fd2a6f 99 MBED_ASSERT((prescale_timer != (uint32_t) -1) && prescale_timer <= 127);
AnnaBridge 182:a56a73fd2a6f 100 MBED_ASSERT((clk_timer % NU_TMRCLK_PER_SEC) == 0);
AnnaBridge 182:a56a73fd2a6f 101 uint32_t cmp_timer = TMR_CMP_MAX;
AnnaBridge 182:a56a73fd2a6f 102 MBED_ASSERT(cmp_timer >= TMR_CMP_MIN && cmp_timer <= TMR_CMP_MAX);
<> 149:156823d33999 103 // Continuous mode
AnnaBridge 184:08ed48f1de7f 104 timer_base->CTL = TIMER_CONTINUOUS_MODE | prescale_timer | TIMER_CTL_CNTDATEN_Msk;
AnnaBridge 184:08ed48f1de7f 105 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 106
AnnaBridge 184:08ed48f1de7f 107 timer_base->CMP = cmp_timer;
AnnaBridge 184:08ed48f1de7f 108 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 182:a56a73fd2a6f 109
<> 149:156823d33999 110 // Set vector
AnnaBridge 182:a56a73fd2a6f 111 NVIC_SetVector(TIMER_MODINIT.irq_n, (uint32_t) TIMER_MODINIT.var);
AnnaBridge 182:a56a73fd2a6f 112
AnnaBridge 187:0387e8f68319 113 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 182:a56a73fd2a6f 114
AnnaBridge 184:08ed48f1de7f 115 TIMER_EnableInt(timer_base);
AnnaBridge 184:08ed48f1de7f 116 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 117
AnnaBridge 184:08ed48f1de7f 118 TIMER_EnableWakeup(timer_base);
AnnaBridge 182:a56a73fd2a6f 119 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 120
AnnaBridge 184:08ed48f1de7f 121 TIMER_Start(timer_base);
AnnaBridge 184:08ed48f1de7f 122 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 184:08ed48f1de7f 123
AnnaBridge 184:08ed48f1de7f 124 /* Wait for timer to start counting and raise active flag */
AnnaBridge 184:08ed48f1de7f 125 while(! (timer_base->CTL & TIMER_CTL_ACTSTS_Msk));
<> 149:156823d33999 126 }
<> 149:156823d33999 127
AnnaBridge 187:0387e8f68319 128 void lp_ticker_free(void)
AnnaBridge 187:0387e8f68319 129 {
AnnaBridge 187:0387e8f68319 130 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 187:0387e8f68319 131
AnnaBridge 187:0387e8f68319 132 /* Stop counting */
AnnaBridge 187:0387e8f68319 133 TIMER_Stop(timer_base);
AnnaBridge 187:0387e8f68319 134 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 187:0387e8f68319 135
AnnaBridge 187:0387e8f68319 136 /* Wait for timer to stop counting and unset active flag */
AnnaBridge 187:0387e8f68319 137 while((timer_base->CTL & TIMER_CTL_ACTSTS_Msk));
AnnaBridge 187:0387e8f68319 138
AnnaBridge 187:0387e8f68319 139 /* Disable wakeup */
AnnaBridge 187:0387e8f68319 140 TIMER_DisableWakeup(timer_base);
AnnaBridge 187:0387e8f68319 141 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 187:0387e8f68319 142
AnnaBridge 187:0387e8f68319 143 /* Disable interrupt */
AnnaBridge 187:0387e8f68319 144 TIMER_DisableInt(timer_base);
AnnaBridge 187:0387e8f68319 145 wait_us((NU_US_PER_SEC / NU_TMRCLK_PER_SEC) * 3);
AnnaBridge 187:0387e8f68319 146
AnnaBridge 187:0387e8f68319 147 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 187:0387e8f68319 148
AnnaBridge 187:0387e8f68319 149 /* Disable IP clock */
AnnaBridge 187:0387e8f68319 150 CLK_DisableModuleClock(TIMER_MODINIT.clkidx);
AnnaBridge 187:0387e8f68319 151
AnnaBridge 187:0387e8f68319 152 ticker_inited = 0;
AnnaBridge 187:0387e8f68319 153 }
AnnaBridge 187:0387e8f68319 154
<> 149:156823d33999 155 timestamp_t lp_ticker_read()
AnnaBridge 182:a56a73fd2a6f 156 {
AnnaBridge 182:a56a73fd2a6f 157 if (! ticker_inited) {
<> 149:156823d33999 158 lp_ticker_init();
<> 149:156823d33999 159 }
<> 149:156823d33999 160
AnnaBridge 184:08ed48f1de7f 161 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 182:a56a73fd2a6f 162
AnnaBridge 182:a56a73fd2a6f 163 return (TIMER_GetCounter(timer_base) / NU_TMRCLK_PER_TICK);
<> 149:156823d33999 164 }
<> 149:156823d33999 165
<> 149:156823d33999 166 void lp_ticker_set_interrupt(timestamp_t timestamp)
<> 149:156823d33999 167 {
AnnaBridge 182:a56a73fd2a6f 168 /* In continuous mode, counter will be reset to zero with the following sequence:
AnnaBridge 182:a56a73fd2a6f 169 * 1. Stop counting
AnnaBridge 182:a56a73fd2a6f 170 * 2. Configure new CMP value
AnnaBridge 182:a56a73fd2a6f 171 * 3. Restart counting
AnnaBridge 182:a56a73fd2a6f 172 *
AnnaBridge 182:a56a73fd2a6f 173 * This behavior is not what we want. To fix it, we could configure new CMP value
AnnaBridge 182:a56a73fd2a6f 174 * without stopping counting first.
AnnaBridge 182:a56a73fd2a6f 175 */
AnnaBridge 184:08ed48f1de7f 176 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 174:b96e65c34a4d 177
AnnaBridge 182:a56a73fd2a6f 178 /* NOTE: Because H/W timer requests min compare value, our implementation would have alarm delay of
AnnaBridge 182:a56a73fd2a6f 179 * (TMR_CMP_MIN - interval_clk) clocks when interval_clk is between [1, TMR_CMP_MIN). */
AnnaBridge 182:a56a73fd2a6f 180 uint32_t cmp_timer = timestamp * NU_TMRCLK_PER_TICK;
AnnaBridge 182:a56a73fd2a6f 181 cmp_timer = NU_CLAMP(cmp_timer, TMR_CMP_MIN, TMR_CMP_MAX);
AnnaBridge 184:08ed48f1de7f 182
AnnaBridge 187:0387e8f68319 183 /* NOTE: Rely on LPTICKER_DELAY_TICKS to be non-blocking. */
AnnaBridge 182:a56a73fd2a6f 184 timer_base->CMP = cmp_timer;
AnnaBridge 187:0387e8f68319 185
AnnaBridge 187:0387e8f68319 186 /* We can call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 187 NVIC_EnableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 188 }
<> 149:156823d33999 189
<> 149:156823d33999 190 void lp_ticker_disable_interrupt(void)
<> 149:156823d33999 191 {
AnnaBridge 187:0387e8f68319 192 /* We cannot call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 193 NVIC_DisableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 194 }
<> 149:156823d33999 195
<> 149:156823d33999 196 void lp_ticker_clear_interrupt(void)
<> 149:156823d33999 197 {
AnnaBridge 187:0387e8f68319 198 /* To avoid sync issue, we clear TIF/TWKF simultaneously rather than call separate
AnnaBridge 187:0387e8f68319 199 * driver API:
AnnaBridge 187:0387e8f68319 200 *
AnnaBridge 187:0387e8f68319 201 * TIMER_ClearIntFlag((TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname));
AnnaBridge 187:0387e8f68319 202 * TIMER_ClearWakeupFlag((TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname));
AnnaBridge 187:0387e8f68319 203 */
AnnaBridge 187:0387e8f68319 204 TIMER_T *timer_base = (TIMER_T *) NU_MODBASE(TIMER_MODINIT.modname);
AnnaBridge 187:0387e8f68319 205 timer_base->INTSTS = TIMER_INTSTS_TIF_Msk | TIMER_INTSTS_TWKF_Msk;
<> 149:156823d33999 206 }
<> 149:156823d33999 207
AnnaBridge 182:a56a73fd2a6f 208 void lp_ticker_fire_interrupt(void)
<> 149:156823d33999 209 {
AnnaBridge 182:a56a73fd2a6f 210 // NOTE: This event was in the past. Set the interrupt as pending, but don't process it here.
AnnaBridge 182:a56a73fd2a6f 211 // This prevents a recursive loop under heavy load which can lead to a stack overflow.
AnnaBridge 182:a56a73fd2a6f 212 NVIC_SetPendingIRQ(TIMER_MODINIT.irq_n);
AnnaBridge 187:0387e8f68319 213
AnnaBridge 187:0387e8f68319 214 /* We can call ticker_irq_handler now. */
AnnaBridge 187:0387e8f68319 215 NVIC_EnableIRQ(TIMER_MODINIT.irq_n);
<> 149:156823d33999 216 }
<> 149:156823d33999 217
AnnaBridge 182:a56a73fd2a6f 218 const ticker_info_t* lp_ticker_get_info()
<> 149:156823d33999 219 {
AnnaBridge 182:a56a73fd2a6f 220 static const ticker_info_t info = {
AnnaBridge 182:a56a73fd2a6f 221 NU_TMRCLK_PER_SEC / NU_TMRCLK_PER_TICK,
AnnaBridge 182:a56a73fd2a6f 222 NU_TMR_MAXCNT_BITSIZE
AnnaBridge 182:a56a73fd2a6f 223 };
AnnaBridge 182:a56a73fd2a6f 224 return &info;
AnnaBridge 182:a56a73fd2a6f 225 }
AnnaBridge 182:a56a73fd2a6f 226
AnnaBridge 182:a56a73fd2a6f 227 static void tmr1_vec(void)
AnnaBridge 182:a56a73fd2a6f 228 {
AnnaBridge 187:0387e8f68319 229 lp_ticker_clear_interrupt();
AnnaBridge 184:08ed48f1de7f 230
AnnaBridge 182:a56a73fd2a6f 231 // NOTE: lp_ticker_set_interrupt() may get called in lp_ticker_irq_handler();
AnnaBridge 182:a56a73fd2a6f 232 lp_ticker_irq_handler();
<> 149:156823d33999 233 }
AnnaBridge 182:a56a73fd2a6f 234
<> 149:156823d33999 235 #endif