Rev. 1.10
66
October 23, 2020
Rev. 1.10
67
October 23, 2020
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
FAST Mode
This is one of the main operating modes where the microcontroller has all of its functions
operational and where the system clock is provided by one of the high speed oscillators. This mode
operates allowing the microcontroller to operate normally with a clock source will come from one
of the high speed oscillators, either the HXT or HIRC oscillator, selected by the FHS bit in the SCC
register. The high speed oscillator will however first be divided by a ratio ranging from 1 to 64,
the actual ratio being selected by the CKS2~CKS0 bit in the SCC register. Although a high speed
oscillator is used, running the microcontroller at a divided clock ratio reduces the operating current.
SLOW Mode
This is also a mode where the microcontroller operates normally although now with a slower speed
clock source. The clock source used will be from f
SUB
. The f
SUB
clock is derived from either the
LIRC or LXT oscillator determined by the FSS bit in the SCC register.
SLEEP Mode
The SLEEP Mode is entered when a HALT instruction is executed and when the FHIDEN and
FSIDEN bit are low. In the SLEEP mode the CPU will be stopped. The f
SUB
clock provided to the
peripheral function will also be stopped, too. However the f
LIRC
clock can continue to operate if the
WDT function is enabled by the WDTC register.
IDLE0 Mode
The IDLE0 Mode is entered when a HALT instruction is executed and when the FHIDEN bit in the
SCC register is low and the FSIDEN bit in the SCC register is high. In the IDLE0 Mode the CPU
will be switched off but the low speed oscillator will be turned on to drive some peripheral functions.
IDLE1 Mode
The IDLE1 Mode is entered when a HALT instruction is executed and when the FHIDEN bit in the
SCC register is high and the FSIDEN bit in the SCC register is high. In the IDLE1 Mode the CPU
will be switched off but both the high and low speed oscillators will be turned on to provide a clock
source to keep some peripheral functions operational.
IDLE2 Mode
The IDLE2 Mode is entered when a HALT instruction is executed and when the FHIDEN bit in
the SCC register is high and the FSIDEN bit in the SCC register is low. In the IDLE2 Mode the
CPU and low speed oscillator will be switched off but the high speed oscillator will be turned on to
provide a clock source to keep some peripheral functions operational.
Control Registers
The registers, SCC, HIRCC, HXTC and LXTC, are used to control the system clock and the
corresponding oscillator configurations.
Register
Name
Bit
7
6
5
4
3
2
1
0
SCC
CKS2
CKS1
CKS0
—
FHS
FSS
FHIDEN FSIDEN
HIRCC
—
—
—
—
HIRC1
HIRC0
HIRCF
HIRCEN
HXTC
—
—
—
—
—
HXTM
HXTF
HXTEN
LXTC
—
—
—
—
—
LXTSP
LXTF
LXTEN
System Operating Mode Control Register List