BC68F2420BC68F2420 Datasheet, PDF (58/116 Pages) Holtek Semiconductor Inc – 315/433MHz RF Super-regenerative Receiver SoC Flash MCU

BC68F2420
315/433MHz RF Super-regenerative
Receiver SoC Flash MCU
TM Interrupts
The Compact and Standard type TMs each has two internal interrupts, the internal comparator A
or comparator P, which generate a TM interrupt when a compare match condition occurs. When a
TM interrupt is generated, it can be used to clear the counter and also to change the state of the TM
output pin.
TM External Pins
Each of the TMs, irrespective of what type, has one TM input pin, with the label xTCK. The xTM
input pin, xTCK, is essentially a clock source for the xTM and is selected using the xTCK2~xTCK0
bits in the xTMC0 register. This external TM input pin allows an external clock source to drive the
internal TM. The xTCK input pin can be chosen to have either a rising or falling active edge. The
xTCK pin is also used as the external trigger input pin in single pulse output mode.
For the STM, the other input pin, STPI, is the capture input whose active edge can be a rising edge,
a falling edge or both rising and falling edges and the active edge transition type is selected using
the STIO1~STIO0 bits in the STMC1 register.
The TMs each have two output pins with the label xTP and xTPB. When the TM is in the Compare
Match Output Mode, these pins can be controlled by the TM to switch to a high or low level or to
toggle when a compare match situation occurs. The external xTP and xTPB output pins are also the
pins where the TM generates the PWM output waveform. As the TM input and output pins are pin-
shared with other functions, the TM input and output function must first be setup using relevant pin-
shared function selection register described in the Pin-shared Function section.
Input
CTCK
CTM
Output
CTP, CTPB
Input
STCK, STPI
STM
Output
STP, STPB
TM External Pins
TM Input/Output Pin Selection
Selecting to have a TM input/output or whether to retain its other shared function is implemented
using the relevant pin-shared function selection registers, with the corresponding selection bits in
each pin-shared function register corresponding to a TM input/output pin. Configuring the selection
bits correctly will setup the corresponding pin as a TM input/output. The details of the pin-shared
function selection are described in the pin-shared function section.
TCK input
CTCK
CTM
CCR output/
PWM signal
CTP
CTPB
CTM Function Pin Control Block Diagram
Rev. 1.00
58
May 24, 2017