Timer

1. Overview

Each timer group (Timer0/Timer1) has three 32-bit up counters driven by a shared 4-bit prescaler. Timers can raise periodic interrupts or act as hardware clocks.

See: Timer Driver Guide

2. Code Path

CLI: components/bk_cli/cli_timer.c
Driver: middleware/driver/timer/timer_driver.c

3. Configuration

Macros include CONFIG_TIMER (enable driver/CLI), CONFIG_TIMER_SUPPORT_ID_BITS (channel partition between CPUs), CONFIG_TIMER_US (microsecond delay APIs), and optional low-power callbacks.

4. Channel Mapping

No GPIO assignment required. Total of 6 channels:

CP: channels 0–2 (channel 2 feeds watchdog)
AP: channels 3–5

5. CLI Commands

Timer CLI commands
Command	Param	Description
`timer {id} start {period}`	`id`: channel (AP: 3–5); `period`: milliseconds	Enable timer; ISR triggers periodically
`timer {id} read`	`id`: channel	Read the counter value
`timer {id} get_period`	`id`: channel	Read the programmed period value
`timer {id} stop`	`id`: channel	Stop the timer and disable its interrupt
`timer {id} enable`	`id`: channel	Set the enable bit
`timer {id} disable`	`id`: channel	Clear the enable bit

6. Demo

Example flow on channel 3 (prefix with cpu1 for AP commands):

cpu1 timer 3 start 2000 – start timer; ISR logs every 2 seconds.
cpu1 timer 3 read – read counter.
cpu1 timer 3 get_period – view programmed period value.
cpu1 timer 3 stop – stop timer.
cpu1 timer 3 enable / disable – toggle counting.