ST7LITE25F2 View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7LITE25F2
STMicroelectronics
'ST7LITE25F2' PDF : 170 Pages View PDF
ST7LITE20F2 ST7LITE25F2 ST7LITE29F2
Supply, reset and clock management
tSTAB (see Figure 12 below and Figure 64: RC oscillator and PLL characteristics (tested
for TA = -40 to +85°C) @ VDD = 4.5 to 5.5 V).
Refer to Section 7.6.4: Register description for a description of the LOCKED bit in the
SICSR register.
7.3
Note:
Register description
Main clock control/status register (MCCSR)
Read / Write
Reset value: 0000 0000 (00h)
7
0
0
0
0
0
0
0
MCO
SMS
● Bits 7:2 = Reserved, must be kept cleared
● Bit 1 = MCO Main Clock Out enable
This bit is read/write by software and cleared by hardware after a reset. This bit allows
to enable the MCO output clock.
0: MCO clock disabled, I/O port free for general purpose I/O.
1: MCO clock enabled.
● Bit 0 = SMS Slow Mode select
This bit is read/write by software and cleared by hardware after a reset. This bit selects
the input clock fOSC2 or fOSC2/32.
0: Normal mode (fCPU = fOSC2
1: Slow mode (fCPU = fOSC2/32)
RC control register (RCCR)
Read / Write
Reset value: 1111 1111 (FFh)
7
CR70
CR60
CR50
CR40
CR30
CR20
CR10
0
CR0
● Bits 7:0 = CR[7:0] RC oscillator frequency adjustment bits
These bits must be written immediately after reset to adjust the RC oscillator frequency
and to obtain an accuracy of 1%. The application can store the correct value for each
voltage range in EEPROM and write it to this register at startup.
00h = maximum available frequency
FFh = lowest available frequency
To tune the oscillator, write a serie of different values in the register until the correct
frequency is reached. The fastest method is to use a dichotomy starting with 80h.
Doc ID 8349 Rev 5
35/166
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