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https://github.com/tinygo-org/tinygo.git
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Dima Jolkin
101 lines
3.0 KiB
Go
101 lines
3.0 KiB
Go
//go:build esp32s3
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package runtime
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import (
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"device/esp"
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"machine"
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)
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// This is the function called on startup after the flash (IROM/DROM) is
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// initialized and the stack pointer has been set.
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//
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//export main
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func main() {
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// This initialization configures the following things:
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// * It disables all watchdog timers. They might be useful at some point in
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// the future, but will need integration into the scheduler. For now,
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// they're all disabled.
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// * It sets the CPU frequency to 240MHz, which is the maximum speed allowed
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// for this CPU. Lower frequencies might be possible in the future, but
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// running fast and sleeping quickly is often also a good strategy to save
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// power.
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// TODO: protect certain memory regions, especially the area below the stack
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// to protect against stack overflows. See
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// esp_cpu_configure_region_protection in ESP-IDF.
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// Disable RTC watchdog.
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esp.RTC_CNTL.WDTWPROTECT.Set(0x50D83AA1)
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esp.RTC_CNTL.WDTCONFIG0.Set(0)
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esp.RTC_CNTL.WDTWPROTECT.Set(0x0) // Re-enable write protect
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// Disable Timer 0 watchdog.
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esp.TIMG1.WDTWPROTECT.Set(0x50D83AA1) // write protect
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esp.TIMG1.WDTCONFIG0.Set(0) // disable TG0 WDT
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esp.TIMG1.WDTWPROTECT.Set(0x0) // Re-enable write protect
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esp.TIMG0.WDTWPROTECT.Set(0x50D83AA1) // write protect
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esp.TIMG0.WDTCONFIG0.Set(0) // disable TG0 WDT
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esp.TIMG0.WDTWPROTECT.Set(0x0) // Re-enable write protect
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// Disable super watchdog.
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esp.RTC_CNTL.SWD_WPROTECT.Set(0x8F1D312A)
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esp.RTC_CNTL.SWD_CONF.Set(esp.RTC_CNTL_SWD_CONF_SWD_DISABLE)
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esp.RTC_CNTL.SWD_WPROTECT.Set(0x0) // Re-enable write protect
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// Change CPU frequency from 20MHz to 80MHz, by switching from the XTAL to the
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// PLL clock source (see table "CPU Clock Frequency" in the reference manual).
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esp.SYSTEM.SetSYSCLK_CONF_SOC_CLK_SEL(1)
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// Change CPU frequency from 80MHz to 240MHz by setting SYSTEM_PLL_FREQ_SEL to
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// 1 and SYSTEM_CPUPERIOD_SEL to 2 (see table "CPU Clock Frequency" in the
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// reference manual).
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// We do this gradually to allow PLL and system to stabilize.
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esp.SYSTEM.SetCPU_PER_CONF_PLL_FREQ_SEL(1)
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// First switch to 160MHz (intermediate step)
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esp.SYSTEM.SetCPU_PER_CONF_CPUPERIOD_SEL(1)
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// Small delay to let PLL stabilize at 160MHz
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for i := 0; i < 1000; i++ {
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_ = esp.SYSTEM.CPU_PER_CONF.Get()
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}
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// Now switch to 240MHz
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esp.SYSTEM.SetCPU_PER_CONF_CPUPERIOD_SEL(2)
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// Small delay to let PLL stabilize at 240MHz
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for i := 0; i < 1000; i++ {
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_ = esp.SYSTEM.CPU_PER_CONF.Get()
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}
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// Clear bss. Repeat many times while we wait for cpu/clock to stabilize
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for x := 0; x < 30; x++ {
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clearbss()
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}
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// Initialize UART.
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machine.InitSerial()
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// Initialize main system timer used for time.Now.
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initTimer()
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// Initialize the heap, call main.main, etc.
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run()
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// Fallback: if main ever returns, hang the CPU.
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exit(0)
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}
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func abort() {
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// lock up forever
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print("abort called\n")
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}
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//go:extern _vector_table
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var _vector_table [0]uintptr
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//go:extern _sbss
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var _sbss [0]byte
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//go:extern _ebss
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var _ebss [0]byte
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