>>>>> "Linge" == Linge Dai <[email protected]> writes:
Linge> Hi, I'm using STM32F4 + libopencm3. I have noticed that some of
Linge> the library functions are declared to have a pointer to registers
Linge> as a parameter:
Linge> For example, in rcc.h: void rcc_peripheral_enable_clock(volatile
Linge> uint32_t *reg, uint32_t en);
Linge> which allows modifying any arbitrary register. The programmers
Linge> need to explicitly enforce restrictions on what to pass to the
Linge> function. Is the API meant to be designed this way?
Linge> A fix to this problem is to wrap the valid register values in an
Linge> enum and use the enum as the function parameter. The new
Linge> declaration of this function will be:
Linge> void rcc_peripheral_enable_clock(clock_enable_reg_t
Linge> clock_enable_reg, uint32_t en);
I think that function is overcomplicated and as you point out dangerous.
What is the advantage of e.g. writing
rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_USBEN);
against directly writing
RCC_APB1ENR |= RCC_APB1ENR_USBEN;
Bye
--
Uwe Bonnes [email protected]
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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