https://github.com/inductivekickback/timeslot
A wrapper around the MPSL Timeslot interface in NCS
https://github.com/inductivekickback/timeslot
ncs nordicsemi zephyr-rtos
Last synced: about 1 month ago
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A wrapper around the MPSL Timeslot interface in NCS
- Host: GitHub
- URL: https://github.com/inductivekickback/timeslot
- Owner: inductivekickback
- Created: 2021-07-23T05:19:43.000Z (almost 4 years ago)
- Default Branch: main
- Last Pushed: 2021-07-31T04:00:49.000Z (over 3 years ago)
- Last Synced: 2024-10-24T16:49:15.426Z (6 months ago)
- Topics: ncs, nordicsemi, zephyr-rtos
- Language: C
- Homepage:
- Size: 28.3 KB
- Stars: 0
- Watchers: 2
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
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README
This wrapper is intended to be a reasonable example of how to use the [Timeslot interface](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/mpsl/doc/timeslot.html) that is built into the [MPSL](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/latest/nrfxlib/mpsl/README.html) in Nordic's [nRF Connect SDK](https://github.com/nrfconnect/sdk-nrf). The objective is to open a recurring timeslot of a fixed length after a BLE connection has been established. Each timeslot has a fixed length and is opened once per Connection Interval. If a library like [ESB](http://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.6.0/nrf/ug_esb.html) is going to be used then a preprocessor symbol called TIMESLOT_CALLS_RADIO_IRQHANDLER can be set to call RADIO_IRQHandler directly from the MPSL_TIMESLOT_SIGNAL_RADIO signal. A "skipped" callback is also provided so proprietary networks can stay in sync when timeslots are blocked or cancelled.
---
### Implementation
Timeslots are synchronized to the active edge of [radio notifications](https://developer.nordicsemi.com/nRF_Connect_SDK/doc/1.6.0/nrfxlib/mpsl/doc/radio_notification.html) so they can follow along with the timing of the BLE connection's Connection Events. The radio notifications feature requires a hardware interrupt vector so a TIMESLOT_IRQN must be defined in timeslot.h (the default is QDEC_IRQn). The MPSL timeslot callback runs as a [Zero Latency IRQ](https://docs.zephyrproject.org/latest/reference/kconfig/CONFIG_ZERO_LATENCY_IRQS.html) and benefits from a hardware interrupt vector so the TIMESLOT_IRQN is also used for lowering the priority of several MPSL interrupts.
---
### Usage
The timeslot_config struct and timeslot_cb structs are required.
```
#include
...
static void timeslot_err_cb(int err)
{
LOG_ERR("Timeslot session error: %d", err);
}
static void timeslot_start_cb(void)
{
LOG_DBG("Timeslot start");
}
static void timeslot_end_cb(void)
{
LOG_DBG("Timeslot end");
}
static void timeslot_skipped_cb(uint8_t count)
{
LOG_INF("Timeslot skipped: %d", count);
}
static void timeslot_stopped_cb(void)
{
LOG_INF("Timeslot stopped");
}
#if !TIMESLOT_CALLS_RADIO_IRQHANDLER
static void radio_irq_cb(void)
{
LOG_DBG("Radio_IRQHandler");
}
#endif
static struct timeslot_cb timeslot_callbacks = {
.error = timeslot_err_cb,
.start = timeslot_start_cb,
.end = timeslot_end_cb,
.skipped = timeslot_skipped_cb,
.stopped = timeslot_stopped_cb,
#if !TIMESLOT_CALLS_RADIO_IRQHANDLER
.radio_irq = radio_irq_cb
#endif
};
static struct timeslot_config timeslot_config = TS_DEFAULT_CONFIG;
...
void main(void)
{
int err = timeslot_open(×lot_config, ×lot_callbacks);
if (err) {
LOG_ERR("timeslot_open failed (err: %d)", err);
}
...
```
A good place to start requesting timeslots is after the BLE connection parameters have settled.
```
static void conn_param_update(struct bt_conn *conn, uint16_t interval, uint16_t latency, uint16_t timeout)
{
...
int err = timeslot_start(500);
if (err) {
LOG_ERR("timeslot_start failed (err=%d)", err);
}
```
If the connection parameters change during the connection then the current timeslots can be stopped so they can be restarted in the "stopped" callback.
```
next_interval = interval;
int err = timeslot_stop();
if (err) {
LOG_ERR("timeslot_stop failed (err=%d)", err);
}
```