SIC63616-(Rev. 1.0) NO. P47
3240-0412
4.5.6 Special output
Besides general purpose DC input/output, the I/O ports P03, P13 and P23 can also be assigned special
output functions in software as shown in Table 4.5.6.1.
Table 4.5.6.1 Special output ports
Port
P03
P13
P23
Special output
BZ
TOUT_A
FOUT
Special output control register
BZE, BZSHT
PTOUT_A
FOUT0–FOUT3
When a special output function is enabled using the special output control register, the corresponding
I/O port is automatically configured for output. The data register, I/O control register, pull-down control
register and input interface level select register of the special output port can be used as general-purpose
registers that do not affect the output status.
TOUT output (P13)
In order for the S1C63616 to provide clock signals to external devices, the P13 terminal can be used to
output the TOUT_A signal (clocks output by the programmable timer).
The TOUT_A signal is enabled to output by the PTOUT_A register. When PTOUT_A is set to "1", the
TOUT_A signal is output from the corresponding port terminal (P13). The I/O control register (IOC13),
pull-down control register (PUL13) and data register (P13) setting is ineffective while the TOUT_A sig-
nal is being output.
When PTOUT_A is set to "0", the port is configured as a general-purpose DC input/output port.
The TOUT_A signal is generated from the underflow and compare-match signals of a programmable
timer. Refer to Section 4.9, "Programmable Timer", for controlling the clock output and frequency.
Since the TOUT_A signal is generated asynchronously from the PTOUT_A register, a hazard of a 1/2
cycle or less is generated when the signal is turned on or off by setting the register.
Figure 4.5.6.1 shows the output waveform of the TOUT_A signal.
PTOUT_A
TOUT_A output
(P13)
0
1
Fig. 4.5.6.1 Output waveform of TOUT_A signal
FOUT output (P23)
In order for the S1C63616 to provide a clock signal to an external device, the FOUT signal (f
OSC1
, f
OSC3
or a divided clock) can be output from the P23 port terminal.
The FOUT signal is enabled to output by the FOUT0–FOUT3 registers. When the output clock frequency
is selected using FOUT0–FOUT3, the FOUT signal is output from the P23 port terminal. The I/O control
register (IOC23), pull-down control register (PUL23) and data register (P23) settings are ineffective
while the FOUT signal is being output.
When FOUT0–FOUT3 are set to "0", the P23 port is configured as a general-purpose DC input/output
port.
The frequency of the FOUT signal can be selected from among 15 settings as shown in Table 4.5.6.2.