STM8S007C8T6TR(2015) View Datasheet(PDF) - STMicroelectronics

Part Name

Description

Manufacturer

STM8S007C8T6TR
(Rev.:2015)

Value line, 24 MHz STM8S 8-bit MCU, 64 Kbytes Flash, true data EEPROM, 10-bit ADC, timers, 2 UARTs, SPI, I²C

STMicroelectronics 

STM8S007C8

Electrical characteristics

Table 30. HSE oscillator characteristics

Symbol

Parameter

Conditions

Min

Typ

Max

Unit

fHSE

External high speed oscillator

frequency

-

1

-

24

MHz

RF Feedback resistor

-

C(1) Recommended load capacitance (2)

-

-

220

-

-

-

k

20

pF

C = 20 pF,

fOSC = 24 MHz

-

IDD(HSE) HSE oscillator power consumption

C = 10 pF,

fOSC = 24 MHz

-

gm Oscillator transconductance

tSU(HSE)(4) Startup time

-

5

VDD is stabilized

-

-

6 (startup)

2 (stabilized)(3)

mA

-

6 (startup)

1.5 (stabilized)(3)

-

-

mA/V

1

-

ms

1. C is approximately equivalent to 2 x crystal Cload.

2. The oscillator selection can be optimized in terms of supply current using a high quality resonator with small Rm value.

Refer to crystal manufacturer for more details

3. Data based on characterization results, not tested in production.

4. tSU(HSE) is the start-up time measured from the moment it is enabled (by software) to a stabilized 24 MHz oscillation is

reached. This value is measured for a standard crystal resonator and it can vary significantly with the crystal manufacturer.

Figure 13. HSE oscillator circuit diagram

Rm

Lm

CO

Cm

Resonator

CL1

OSCIN

Resonator

OSCOUT

CL2

fHSE to core

RF

gm

Consumption

control

STM8

HSE oscillator critical gm formula

gmcrit = 2    fHSE2  Rm2Co + C2

Rm: Notional resistance (see crystal specification) 

Lm: Notional inductance (see crystal specification)

Cm: Notional capacitance (see crystal specification)

Co: Shunt capacitance (see crystal specification)

CL1=CL2=C: Grounded external capacitance

gm >> gmcrit

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