Controlling Clock Output - Epson S1C17704 Technical Manual

13 PWM & CAPTURE TIMER (T16E)

13.6 Controlling Clock Output

The PWM & capture timer can generate the TOUT signal using the compare match signals from the counter.
Figure 13.6.1 shows the PWM & capture timer clock output circuit.
INITOL
Compare A
Compare B
Setting the initial output level
The default output level while the clock output is turned off is 0 (low level). This level can be changed to 1 (high
level) using INITOL (D8/T16E_CTL register).
∗ INITOL: Initial Output Level Select Bit in the PWM Timer Control (T16E_CTL) Register (D8/0x5306)
When INITOL is 0 (default), the initial output level is low. When INITOL is set to 1, the initial output level is
set to high.
The timer output goes to the initial output level when the timer is reset by writing 1 to T16ERST as well as
when the timer output is turned off.
Setting the signal active level
By default, an active high signal (normal low) is generated. This logic can be inverted using INVOUT (D4/
T16E_CTL register). When 1 is written to INVOUT, the timer generates an active low (normal high) signal.
∗ INVOUT: Inverse Output Control Bit in the PWM Timer Control (T16E_CTL) Register (D4/0x5306)
Note that the initial output level set by INITOL is inverted when INVOUT is set to 1.
See Figure 13.6.2 for the waveforms.
Setting the output pin
The TOUT signal generated here can be output from the TOUT (P26) pin, enabling a programmable clock or
PWM signal to be supplied to external devices.
At initial reset, the P26 pin used for the clock output is set for the I/O port and set in input mode. The pin goes
into high-impedance status.
When the pin function is switched to the TOUT output, the pin outputs the level according to the set values of
INITOL and INVOUT. The output pin holds this level until the output level changes due to the counter value
after the timer output is enabled.
13-6
Logic
D Q
Q
Clock
Figure 13.6.1 PWM & Capture Timer Clock Output Circuit
Table 13.6.1 Initial Output Level
INITOL INVOUT
1 1
1 0
0 1
0 0
EPSON
OUTEN INVOUT
Initial output level
Low
High
High
Low
TOUT (P26)
S1C17704 TECHNICAL MANUAL