Holtek HT66F488 Manual page 117

HT66F488/HT66F489
A/D Flash MCU with EEPROM
SIMD Register
Bit 7
�a�e D�
R/W R/W
POR ×
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
by the SPI function, only by the I
function and to set the data transmission clock frequency. Although not connected with the SPI
function, the SIMC0 register is also used to control the Peripheral Clock Prescaler. Register SIMC2
is used for other control functions such as LSB/MSB selection, write collision flag etc.
SIMC0 Register
Bit 7
�a�e SIM2
R/W R/W
POR 1
Bit 7 ~ 5 SIM2~SIM0: SIM Operating Mode Control
000: SPI master mode; SPI clock is f
001: SPI master mode; SPI clock is f
010: SPI master mode; SPI clock is f
011: SPI master mode; SPI clock is f
100: SPI master mode; SPI clock is CTM CCRP match frequency/2
101: SPI slave mode
110: I
111: Unused mode
These bits setup the overall operating mode of the SIM function. As well as selecting
if the I
the SPI Master clock frequency. The SPI clock is a function of the system clock but
can also be chosen to be sourced from the CTM. If the SPI Slave Mode is selected
then the clock will be supplied by an external Master device.
Bit 4 Unimplemented, read as "0"
SIMDBNC1~SIMDBNC0: I
Bit 3 ~ 2
00: No debounce
01: 2 system clocks debounce
1x: 4 system clocks debounce
Bit 1 SIMEN: SIM 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
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 interf ace 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
bits and the SIMEN bit changes from low to high, the contents of the I
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
HAAS, HBB, SRW and RXAK will be set to their default states.
Rev. 1.21
6 5 4
D6 D5 D4
R/W R/W R/W
× × ×
C function. Register SIMC0 is used to control the enable/disable
2
6 5 4
SIM1 SIM� —
R/W R/W —
1 1 —
C slave mode
2
C or SPI function, they are used to control the SPI Master/Slave selection and
2
C Debounce Time Selection
2
C function and the SIM operating current will be
2
11�
3 2 1
D3 D2 D1
R/W R/W R/W
× × ×
C function. The SIMC1 register is not used
2
3 2
SIMDB�C1 SIMDB�C� SIME�
R/W R/W R/W
� �
/4
SYS
/16
SYS
/64
SYS
SUB
C interface via the SIM2~SIM0
2
C flags such as HCF,
2
�ove��e� ��� 2�1�
0
D�
R/W
×
"×": unknown
1 0
SPIICF
R/W
� �
C control bits
2