rp2/modmachine.c: Allow to use the MCU clock for the peripherals.

robert-hh · robert-hh · commit c8e451113231 · 2024-07-06T13:03:21.000+02:00
By default, the peripheral clock for UART and SPI is set to 48 MHz
and will not be affected by the MCU clock change. This can be changed
by a second argument to machine.freq(freq, use_mcu_clk). If use_mcu_clck
is present and True, the mcu_clock is used for UART and SPI. Note
that UART and SPI baud rates may have to be re-configured after changing
the MCU clock.
The peripheral clock cannot be set to arbitrary values. So it follows
either the USB clock of 48MHz or the MCU clock.

Side change: Allow more than one argument for machine.freq().

Signed-off-by: robert-hh &lt;robert@hammelrath.com&gt;
diff --git a/docs/rp2/quickref.rst b/docs/rp2/quickref.rst
@@ -36,7 +36,9 @@ The :mod:`machine` module::
     import machine
 
     machine.freq()          # get the current frequency of the CPU
-    machine.freq(240000000) # set the CPU frequency to 240 MHz
+    machine.freq(240000000) # set the CPU frequency to 240 MHz and keep
+                            # the UART frequency at 48MHz
+    machine.freq(125000000, True) # set the CPU and UART frequency to 125 MHz
 
 The :mod:`rp2` module::
 
diff --git a/extmod/modmachine.c b/extmod/modmachine.c
@@ -109,7 +109,7 @@ static mp_obj_t machine_freq(size_t n_args, const mp_obj_t *args) {
         return mp_const_none;
     }
 }
-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 1, machine_freq);
+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 4, machine_freq);
 
 static mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {
     mp_machine_lightsleep(n_args, args);
diff --git a/ports/rp2/modmachine.c b/ports/rp2/modmachine.c
@@ -96,6 +96,13 @@ static void mp_machine_set_freq(size_t n_args, const mp_obj_t *args) {
     if (!set_sys_clock_khz(freq / 1000, false)) {
         mp_raise_ValueError(MP_ERROR_TEXT("cannot change frequency"));
     }
+    if (n_args > 1 && mp_obj_get_int(args[1]) != 0) {
+        clock_configure(clk_peri,
+            0,
+            CLOCKS_CLK_PERI_CTRL_AUXSRC_VALUE_CLKSRC_PLL_SYS,
+            freq,
+            freq);
+    }
     #if MICROPY_HW_ENABLE_UART_REPL
     setup_default_uart();
     mp_uart_init();

Original file line number	Diff line number	Diff line change
`@@ -109,7 +109,7 @@ static mp_obj_t machine_freq(size_t n_args, const mp_obj_t *args) {`
`109`	`109`	`return mp_const_none;`
`110`	`110`	`}`
`111`	`111`	`}`
`112`		`-MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 1, machine_freq);`
	`112`	`+MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(machine_freq_obj, 0, 4, machine_freq);`
`113`	`113`
`114`	`114`	`static mp_obj_t machine_lightsleep(size_t n_args, const mp_obj_t *args) {`
`115`	`115`	`mp_machine_lightsleep(n_args, args);`