diff options
| author | Jacques Comeaux <jacquesrcomeaux@protonmail.com> | 2023-12-23 14:12:08 -0600 |
|---|---|---|
| committer | Jacques Comeaux <jacquesrcomeaux@protonmail.com> | 2023-12-23 14:12:08 -0600 |
| commit | 8f6eed4e102500204879d848572547b35a267cea (patch) | |
| tree | ad5f5138f9068af37d11e20ac6c87e28c3f92d45 /clocks.s | |
| parent | 987e12b6c90ed3a3606a4948e9d7cad6d6f34026 (diff) | |
Use crystal oscilator for system clock
Diffstat (limited to 'clocks.s')
| -rw-r--r-- | clocks.s | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/clocks.s b/clocks.s new file mode 100644 index 0000000..09a0f6d --- /dev/null +++ b/clocks.s @@ -0,0 +1,18 @@ +.syntax unified +.cpu cortex-m0plus +.thumb + +.equ CLOCKS_BASE, 0x40008000 +.equ CLK_REF_CTRL_OFST, 0x30 +.equ CLK_SYS_CTRL_OFST, 0x3c + +.type setup_clocks, %function +.global setup_clocks + +setup_clocks: + ldr r1, =CLOCKS_BASE + movs r0, 2 // use xosc (=0x2) as clk_ref source + str r0, [r1, CLK_REF_CTRL_OFST] + movs r0, 1 // use auxsrc (default pll_sys, =0x1) as clk_sys source + str r0, [r1, CLK_SYS_CTRL_OFST] + mov pc, lr |