STM32W108CBU6 STMICROELECTRONICS [STMicroelectronics], STM32W108CBU6 Datasheet - Page 41

• Manufacturer Part Number: STM32W108CBU6
• Description: High-performance, IEEE 802.15.4 wireless system-on-chip
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

STM32W108CB, STM32W108HB
5.3.6
31
15
31
15
r
r
r
r
30
14
30
14
r
r
r
r
Table 3.
Clock switching registers
XTAL or OSCHF main clock select register (OSC24M_CTRL)
Address offset: 0x4000 401C
Reset value: 0x0000 0000
CPU clock source select register (CPU_CLK_SEL)
Address offset: 0x4000 4020
Reset value: 0x0000 0000
OSC24M_SEL CPU_CLK_SEL
1 (OSC24M)
1 (OSC24M)
29
13
29
13
0 (OSCHF)
0 (OSCHF)
r
r
r
r
1 OSC24M_EN: When set to ‘1’, 24 MHz crystal oscillator is main clock.
0 OSC24M_SEL: When set to ‘0’, OSCHF is selected. When set to ‘1’, XTAL is selected.
0 CPU_CLK_SEL: When set to ‘0’, 12-MHz CPU clock is selected. When set to ‘1’, 24-MHz CPU
clock is selected. Note that the clock selection also determines if RAM controller is running at
the same speed as the HCLK (CPU_CLK_SEL = ‘1’) or double speed of HCLK (CPU_CLK_SEL
= ‘0’).
28
12
28
12
r
r
r
r
System clock modes
27
11
27
11
r
r
r
r
0 (Normal CPU)
0 (Normal CPU)
1 (Fast CPU)
1 (Fast CPU)
26
10
26
10
r
r
r
r
25
25
9
r
r
9
r
r
Doc ID 16252 Rev 2
24
24
8
r
r
8
12 MHz
12 MHz
24 MHz
24 MHz
r
r
SCLK
23
7
23
r
r
7
r
r
22
6
22
r
r
6
r
r
12 MHz
12 MHz
6 MHz
6 MHz
PCLK
21
5
21
r
r
5
r
r
20
4
r
r
20
4
r
r
Erase Inactive
Program/
12 MHz
12 MHz
24 MHz
6 MHz
Flash
19
3
r
r
19
3
r
r
System modules
18
FCLK
2
r
r
18
2
r
r
Erase Active
OSC24
Program/
M_EN
rws
17
12 MHz
12 MHz
12 MHz
12 MHz
1
rws
r
17
Flash
1
r
LK_SEL
CPU_C
41/179
OSC24
M_SEL
rws
16
rws
0
r
16
0
r