ht82a836r Holtek Semiconductor Inc., ht82a836r Datasheet - Page 47

• Manufacturer Part Number: ht82a836r
• Description: Usb Audio Mcu
• Manufacturer: Holtek Semiconductor Inc.

The SBEN bit determines if pins PC4~PC7 are used as
normal I/O pins or as SPI function pins. If this bit is high
then the pins will be SPI function pins and here pin SCS
will go low if CSEN=1. If the bit is low then the pins will
function as normal I/O pins. Note that when SBEN=1,
then any pull-high resistors connected to pins PC4~PC7
will be disconnected therefore the user hardware should
ensure that external pull-high resistors are added to the
SPI pins if necessary. If CSEN = 0 then the SCS pin will
be in a floating state.
The SPI clock polarity is controlled using the SIO_CPOL
bit in the MODE_CTRL register. If SIO_CPOL = 1, then
the rising edge will be selected. Otherwise if SIO_CPOL
= 0, the falling edge will be selected.
Rev. 1.00
SPI Interface Control Register
SPI Bus Timing
47
The CSEN bit in the SBCR register controls the overall
function of the SPI interface. Setting this bit high, will en-
able the SPI interface by allowing the SCS line to be ac-
tive, which can then be used to control the SPI interface.
If the CSEN bit is low, the SPI interface will be disabled
and the SCS line will be in a floating condition and can
therefore not be used for control of the SPI interface.
The SBEN bit in the SBCR register must also be high
which will change the pin function from a standard I/O to
an SPI function pin. If in the Master Mode the SCK line
will be either high or low depending upon the clock po-
larity configuration option. If in the Slave Mode the SCK
line will be in a floating condition. If SBEN is low then the
bus will be disabled.
HT82A836R
March 20, 2008