Rev. 1.10
90
October 23, 2020
Rev. 1.10
91
October 23, 2020
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
BC66F5652
2.4GHz RF Transceiver A/D Flash MCU
Bit 0
RXPS
: RX input source pin selection
0: PD1
1: PC1
I/O Pin Structures
The accompanying diagram illustrates the internal structure of the I/O logic function. As the exact
logical construction of the I/O pin will differ from this drawing, it is supplied as a guide only to
assist with the functional understanding of the I/O logic function. The wide range of pin-shared
structures does not permit all types to be shown.
M
U
X
VDD
Control Bit
Data Bit
Data Bus
Write Control Register
Chip Reset
Read Control Register
Read Data Register
Write Data Register
System Wake-up
wake-up Select
I/O pin
Weak
Pull-up
Pull-high
Register
Select
Q
D
CK
Q
D
CK
Q
Q
S
S
PA only
Logic Function Input/Output Structure
Programming Considerations
Within the user program, one of the first things to consider is port initialisation. After a reset, all
of the I/O data and port control registers will be set high. This means that all I/O pins will default
to an input state, the level of which depends on the other connected circuitry and whether pull-
high selections have been chosen. If the port control registers are then programmed to set some
pins as outputs, these output pins will have an initial high output value unless the associated port
data registers are first programmed. Selecting which pins are inputs and which are outputs can be
achieved byte-wide by loading the correct values into the appropriate port control register or by
programming individual bits in the port control register using the “SET [m].i” and “CLR [m].i”
instructions. Note that when using these bit control instructions, a read-modify-write operation takes
place. The microcontroller must first read in the data on the entire port, modify it to the required new
bit values and then rewrite this data back to the output ports.
Port A has the additional capability of providing wake-up functions. When the device is in the
SLEEP or IDLE Mode, various methods are available to wake the device up. One of these is a high
to low transition of any of the Port A pins. Single or multiple pins on Port A can be set to have this
function.