Commit e037976e authored by Per Lindgren's avatar Per Lindgren

bare 6 84mhz

parent 2246228d
......@@ -4,12 +4,14 @@
#![feature(used)]
#![no_std]
extern crate f4;
extern crate stm32f40x;
#[macro_use]
extern crate cortex_m_debug;
use stm32f40x::{DWT, GPIOA, GPIOC, RCC};
use f4::clock;
use f4::prelude::*;
use stm32f40x::{DWT, FLASH, GPIOA, GPIOC, RCC};
fn main() {
ipln!("init");
......@@ -17,9 +19,11 @@ fn main() {
let rcc = unsafe { &mut *RCC.get() }; // get the reference to RCC in memory
let gpioa = unsafe { &mut *GPIOA.get() }; // get the reference to GPIOA in memory
let gpioc = unsafe { &mut *GPIOC.get() }; // get the reference to GPIOC in memory
let flash = unsafe { &mut *FLASH.get() }; // get the reference to FLASH in memory
dwt.enable_cycle_counter();
clock_out(rcc, gpioc);
//clock::set_84_mhz(rcc, flash);
idle(dwt, rcc, gpioa);
}
......@@ -59,9 +63,11 @@ fn clock_out(rcc: &mut RCC, gpioc: &mut GPIOC) {
.ospeedr
.modify(|_, w| unsafe { w.ospeedr9().bits(0b11) });
}
// user application
fn idle(dwt: &mut DWT, rcc: &mut RCC, gpioa: &mut GPIOA) {
ipln!("idle");
// power on GPIOA, RM0368 6.3.11
rcc.ahb1enr.modify(|_, w| w.gpioaen().set_bit());
......@@ -144,9 +150,33 @@ fn idle(dwt: &mut DWT, rcc: &mut RCC, gpioa: &mut GPIOA) {
//
// commit your answers (bare6_4)
//
// 5. now reprogram the PC9 to be "Low Speed", and re-run at 64Mz
// 5. now we will put the MCU in 84MHz using the function
// clock::set_84_mhz(rcc, flash);
//
// this function is part of the `f4` support crate (by Johonnes Sjölund)
// besides `rcc` (for clocking) it takes `flash` as a parameter to set
// up correct latency (wait states) for the flash memory (where our
// program typically resides). This is required since the flash cannot
// operate at the full 84MHz, so the MCU has to wait for the memory.
//
// repeat the experiment 2.
// what is the frequency of MCO2 read by the oscilloscope
// ** your answer here **
//
// compute the value of SYSCLK based on the oscilloscope reading
// ** your answer here **
// what is the peak to peak reading of the signal
//
// ** your answer here **
//
// make a screen dump or photo of the oscilloscope output
// sove the the picture as "bare_6_84mhz_high_speed"
//
// commit your answers (bare6_5)
//
// 6. now reprogram the PC9 to be "Low Speed", and re-run at 64Mz
//
// did the frequency change in comparison to assignment 4.
// did the frequency change in comparison to assignment 5.
// ** your answer here **
//
// what is the peak to peak reading of the signal
......@@ -156,6 +186,6 @@ fn idle(dwt: &mut DWT, rcc: &mut RCC, gpioa: &mut GPIOA) {
// ** your answer here **
//
// make a screen dump or photo of the oscilloscope output
// sove the the picture as "bare_6_64mhz_low_speed"
// sove the the picture as "bare_6_84mhz_low_speed"
//
// commit your answers (bare6_24)
// commit your answers (bare6_6)
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