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jesd204sync: cleanup DDMTD averaging code

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This commit is contained in:
Sebastien Bourdeauducq 2019-01-28 14:14:50 +08:00
parent 2b0d63db23
commit cfe66549ff
1 changed files with 12 additions and 9 deletions
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21
artiq/firmware/libboard_artiq/jesd204sync.rs
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@ -25,22 +25,21 @@ fn average_phases(phases: &[i32], modulo: i32) -> i32 {
const DDMTD_N_SHIFT: i32 = 6; const DDMTD_N_SHIFT: i32 = 6;
const DDMTD_N: i32 = 1 << DDMTD_N_SHIFT; const DDMTD_N: i32 = 1 << DDMTD_N_SHIFT;
const SYSREF_SH_PRECISION_SHIFT: i32 = 5;
const SYSREF_SH_PRECISION: i32 = 1 << SYSREF_SH_PRECISION_SHIFT;
const SYSREF_SH_MOD: i32 = 1 << (DDMTD_N_SHIFT + SYSREF_SH_PRECISION_SHIFT);
fn measure_ddmdt_phase_raw() -> i32 { fn measure_ddmdt_phase_raw() -> i32 {
unsafe { csr::sysref_ddmtd::dt_read() as i32 } unsafe { csr::sysref_ddmtd::dt_read() as i32 }
} }
fn measure_ddmdt_phase() -> i32 { fn measure_ddmdt_phase() -> i32 {
let mut measurements = [0; SYSREF_SH_PRECISION as usize]; const AVG_PRECISION_SHIFT: i32 = 5;
for i in 0..SYSREF_SH_PRECISION { const AVG_PRECISION: i32 = 1 << AVG_PRECISION_SHIFT;
measurements[i as usize] = measure_ddmdt_phase_raw() << SYSREF_SH_PRECISION_SHIFT; const AVG_MOD: i32 = 1 << (DDMTD_N_SHIFT + AVG_PRECISION_SHIFT);
let mut measurements = [0; AVG_PRECISION as usize];
for i in 0..AVG_PRECISION {
measurements[i as usize] = measure_ddmdt_phase_raw() << AVG_PRECISION_SHIFT;
clock::spin_us(10); clock::spin_us(10);
} }
average_phases(&measurements, SYSREF_SH_MOD) >> SYSREF_SH_PRECISION_SHIFT average_phases(&measurements, AVG_MOD) >> AVG_PRECISION_SHIFT
} }
fn test_ddmtd_stability() -> Result<(), &'static str> { fn test_ddmtd_stability() -> Result<(), &'static str> {
@ -116,6 +115,10 @@ fn sysref_sh_error() -> bool {
} }
} }
const SYSREF_SH_PRECISION_SHIFT: i32 = 5;
const SYSREF_SH_PRECISION: i32 = 1 << SYSREF_SH_PRECISION_SHIFT;
const SYSREF_SH_MOD: i32 = 1 << (DDMTD_N_SHIFT + SYSREF_SH_PRECISION_SHIFT);
#[derive(Default)] #[derive(Default)]
struct SysrefShLimits { struct SysrefShLimits {
rising_phases: [i32; SYSREF_SH_PRECISION as usize], rising_phases: [i32; SYSREF_SH_PRECISION as usize],