From bb04b082a7fddd654f067dad7749386ba7f6bb24 Mon Sep 17 00:00:00 2001 From: Sebastien Bourdeauducq Date: Tue, 31 Dec 2019 11:36:26 +0800 Subject: [PATCH] wrpll: clarify comment --- artiq/firmware/libboard_artiq/wrpll.rs | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/artiq/firmware/libboard_artiq/wrpll.rs b/artiq/firmware/libboard_artiq/wrpll.rs index 29910723d..b42166670 100644 --- a/artiq/firmware/libboard_artiq/wrpll.rs +++ b/artiq/firmware/libboard_artiq/wrpll.rs @@ -267,7 +267,8 @@ mod si549 { fn get_frequencies() -> (u32, u32, u32) { unsafe { csr::wrpll::frequency_counter_update_en_write(1); - clock::spin_us(200_000); // wait for at least one update + // wait for at least one full update cycle (> 2 timer periods) + clock::spin_us(200_000); csr::wrpll::frequency_counter_update_en_write(0); let helper = csr::wrpll::frequency_counter_counter_helper_read(); let main = csr::wrpll::frequency_counter_counter_rtio_read();