ST7FLU05MCE View Datasheet(PDF) - STMicroelectronics
Part Name
Description
MFG CO.
ST7FLU05MCE
STMicroelectronics
'ST7FLU05MCE' PDF : 124 Pages View PDF
ST7LUS5, ST7LU05, ST7LU09
Supply, reset and clock management
6
Supply, reset and clock management
The device includes a range of utility features for securing the application in critical
situations (for example in case of a power brown-out), and reducing the number of external
components.
Main features
● Clock management
– 8 MHz internal RC oscillator (enabled by option byte)
– External clock input (enabled by option byte)
● Reset Sequence Manager (RSM)
● System integrity management (SI) - Main supply low voltage detection (LVD) with reset
t(s) generation (enabled by option byte)
duc 6.1
Internal RC oscillator adjustment
Pro t(s) The ST7 contains an internal RC oscillator with a specific accuracy for a given device,
temperature and voltage. It can be selected as the start up clock through the CKSEL[1:0]
te c option bits (see Section 14.1 on page 131). It must be calibrated to obtain the frequency
le u required in the application. This is done by software writing a 10-bit calibration value in the
so rod RCCR (RC control register) and in the bits [6:5] in the SICSR (SI control status register).
b P Whenever the microcontroller is reset, the RCCR returns to its default value (FFh), that is,
each time the device is reset, the calibration value must be loaded in the RCCR. Predefined
- O te calibration values are stored in Flash memory for 3.3 and 5V VDD supply voltages at TAmax,
) le as shown in the following Table 6.
ct(s bso Table 6. RCCR calibration values
u O RCCR
rod ) - RCCRH0
P t(s RCCRL0
te c RCCRH1
le du RCCRL1
Conditions
VDD = 5V, TAmax, fRC = 8 MHz(1)
VDD = 3.3V, TAmax, fRC = 8 MHz(1)
ST7LUxx address
DEE0h(2) (CR[9:2] bits)
DEE1h(2) (CR[1:0] bits)
DEE2h(2) (CR[9:2] bits)
DEE3h(2) (CR[1:0] bits)
so ro 1. xxRCCR0 and RCCR1 calibrated within these conditions in order to reach RC accuracy as mentionned in
b P Table 65: General operating conditions on page 104
O te2. DEE0h, DEE1h, DEE2h and DEE3h are located in a reserved area but are special bytes containing also
the RC calibration values which are read-accessible only in user mode. If all the Flash space (including the
le RC calibration value locations) has been erased (after the readout protection removal), then the RC
o calibration values can still be obtained through these two addresses.
bs Note: 1 In ICC mode, the internal RC oscillator is forced as a clock source, regardless of the
O selection in the option byte. Refer to Note 5 in Section 4.4 for further details.
2 See Chapter 12: Electrical characteristics on page 102 for more information on the
frequency and accuracy of the RC oscillator.
3 To improve clock stability and frequency accuracy, it is recommended to place a decoupling
capacitor, typically 100nF, between the VDD and VSS pins as close as possible to the ST7
device.
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