Rev. 1.10
144
October 23, 2020
Rev. 1.10
145
October 23, 2020
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
SPI Control Registers
There are also two control registers for the SPI interface, SIMC0 and SIMC2. Note that the SIMC2
register also has the name SIMA which is used by the I
2
C function. The SIMC0 register is used to
control the enable/disable function and to set the data transmission clock frequency. The SIMC2
register is used for other control functions such as LSB/MSB selection, write collision flag etc.
• SIMC0 Register
Bit
7
6
5
4
3
2
1
0
Name
SIM2
SIM1
SIM0
—
SIMDEB1 SIMDEB0 SIMEN
SIMICF
R/W
R/W
R/W
R/W
—
R/W
R/W
R/W
R/W
POR
1
1
1
—
0
0
0
0
Bit 7~5
SIM2~SIM0
: SIM Operating Mode Control
000: SPI master mode; SPI clock is f
SYS
/4
001: SPI master mode; SPI clock is f
SYS
/16
010: SPI master mode; SPI clock is f
SYS
/64
011: SPI master mode; SPI clock is f
SUB
100: SPI master mode; SPI clock is PTM CCRP interrupt frequency/2
101: SPI slave mode
110: I
2
C slave mode
111: Non SIM function
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I
2
C or SPI function, they are used to control the SPI Master/Slave selection and
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from PTM CCRP interrupt and f
SUB
. If the SPI Slave
Mode is selected then the clock will be supplied by an external Master device.
Bit 4
Unimplemented, read as “0”
Bit 3~2
SIMDEB1~SIMDEB0
: I
2
C Debounce Time Selection
These bits are only available when the SIM is configured to operate in the I
2
C mode.
Refer to the I
2
C register section.
Bit 1
SIMEN
: SIM Enable Control
0: Disable
1: Enable
The bit is the overall on/off control for the SIM interface. When the SIMEN bit is
cleared to zero to disable the SIM interface, the SDI, SDO, SCK and SCS, or SDA
and SCL lines will lose their SPI or I
2
C function and the SIM operating current will be
reduced to a minimum value. When the bit is high the SIM interface is enabled. If the
SIM is configured to operate as an SPI interface via the SIM2~SIM0 bits, the contents
of the SPI control registers will remain at the previous settings when the SIMEN bit
changes from low to high and should therefore be first initialised by the application
program. If the SIM is configured to operate as an I
2
C interface via the SIM2~SIM0
bits and the SIMEN bit changes from low to high, the contents of the I
2
C control bits
such as HTX and TXAK will remain at the previous settings and should therefore be
first initialised by the application program while the relevant I
2
C flags such as HCF,
HAAS, HBB, SRW and RXAK will be set to their default states.
Bit 0
SIMICF
:
SIM SPI Incomplete Flag
0: SIM SPI conmunication incompleted did not occur
1: SIM SPI conmunication incompleted occurred
This bit is only available when the SIM is configured to operate in an SPI slave mode.
If the SPI operates in the slave mode with the SIMEN and CSEN bits both being set
to 1 but the SCS line is pulled high by the external master device before the SPI data
transfer is completely finished, the SIMICF bit will be set to 1 together with the TRF
bit set high. When this condition occurs, the corresponding interrupt will occur if the
interrupt function is enabled. However, the TRF bit will not be set to 1 if the SIMICF
bit is set to 1 by software application program.