cpu_clock.h
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1 /*
2  * Copyright (C) 2021 Gerson Fernando Budke <nandojve@gmail.com>
3  *
4  * This file is subject to the terms and conditions of the GNU Lesser
5  * General Public License v2.1. See the file LICENSE in the top level
6  * directory for more details.
7  */
8 
24 #ifndef CPU_CLOCK_H
25 #define CPU_CLOCK_H
26 
27 #include <stdint.h>
28 
29 #ifdef __cplusplus
30 extern "C" {
31 #endif
32 
38 enum {
39  CPU_ATXMEGA_CLK_SCALE_DIV1 = 0,
40  CPU_ATXMEGA_CLK_SCALE_DIV2 = 1,
41  CPU_ATXMEGA_CLK_SCALE_DIV4 = 3,
42  CPU_ATXMEGA_CLK_SCALE_DIV8 = 5,
43  CPU_ATXMEGA_CLK_SCALE_DIV16 = 7,
44  CPU_ATXMEGA_CLK_SCALE_DIV32 = 9,
45  CPU_ATXMEGA_CLK_SCALE_DIV64 = 11,
46  CPU_ATXMEGA_CLK_SCALE_DIV128 = 13,
47  CPU_ATXMEGA_CLK_SCALE_DIV256 = 15,
48  CPU_ATXMEGA_CLK_SCALE_DIV512 = 17,
49 };
50 
51 enum {
52  CPU_ATXMEGA_BUS_SCALE_DIV1_1 = 0,
53  CPU_ATXMEGA_BUS_SCALE_DIV1_2 = 1,
54  CPU_ATXMEGA_BUS_SCALE_DIV4_1 = 2,
55  CPU_ATXMEGA_BUS_SCALE_DIV2_2 = 3,
56 };
57 
61 static inline void atxmega_set_prescaler(uint8_t clk_scale, uint8_t bus_scale)
62 {
63  /* Disable CCP for Protected IO register and set new value
64  * Set system clock prescalers to zero. PSCTRL contains A Prescaler
65  * Value and one value for and B and C Prescaler
66  */
67  _PROTECTED_WRITE(CLK.PSCTRL, clk_scale | bus_scale);
68 }
69 
70 #ifdef __cplusplus
71 }
72 #endif
73 
74 #endif /* CPU_CLOCK_H */
atxmega_set_prescaler
static void atxmega_set_prescaler(uint8_t clk_scale, uint8_t bus_scale)
Initializes system clock prescaler.
Definition: cpu_clock.h:61