PD17012_15 Datasheet, PDF (199/320 Pages) Renesas Technology Corp – 4-BIT SINGLE-CHIP MICROCONTROLLERS WITH DIGITAL TUNING SYSTEM HARDWARE

µPD17012, 17P012
17.2 Input/Output Select Block and Gate Time Control Block
Figure 17-2 shows the configuration of the input/output select block and gate time control block.
The input/output select block consists of an IF counter input select block and FCG I/O select block.
The IF counter input select block selects whether the frequency counter is used as an IF counter or an external
gate counter, by using the IF counter mode select register. When the frequency counter is used as the IF counter,
either P1B3/FMIFC or P1B2/AMIFC pin and a count mode are selected. The pin not used for the IF counter is used
as a general-purpose input port pin.
The FCG I/O select block selects a pin to be used from either the P0B3/FCG1 or P0B2/FCG0 pin by using the FCG
channel select register, when the frequency counter is used as the external gate counter. The pin not used is used
as a general-purpose I/O port pin.
When using the frequency counter as the external gate counter, the pin to be used must be set in the input mode
by using the port 0B bit I/O select register. This is because the pin is set in the general-purpose output port mode
if it is set in the output mode even if the external gate counter function is selected by the IF counter mode select register
and FCG channel select register.
The gate time control block selects gate time by using the IF counter mode select register when the frequency
counter is used as the IF counter, or a count frequency when the frequency counter is used as the external gate counter.
Figure 17-3 shows the configuration of the IF counter mode select register.
Figure 17-4 shows the configuration of the FCG channel select register.
Figure 17-2. Configuration of I/O Select Block and Gate Time Control Block
FCGCH1 flag
FCGCH0 flag
IFCMD1 flag
IFCMD0 flag
P0B3/FCG1
P0B2/FCG0
Selector
I/O port
P1B3/FMIFC
FCG
Selector
Gate signal
generator
IFCCK1 flag
IFCCK0 flag
Frequency
generator
Gate signal
To start/stop control
block
P1B2/AMIFC
Input port
FMIFC
AMIFC
Frequency
Data Sheet U10101EJ4V0DS
197