Z86D73 Datasheet, PDF (55/92 Pages) Zilog, Inc. – 40/44/48-Pin Low-Voltage IR OTP

Z86D73
40/44/48-Pin Low-Voltage IR OTP
49
T16 Transmit Mode
In Normal or Ping-Pong Mode, the output of T16 when not enabled, is dependent
on CTR1, D0. If it is a 0, T16_OUT is a 1; if it is a 1, T16_OUT is 0. You can force
the output of T16 to either a 0 or 1 whether it is enabled or not by programming
CTR1 D3; D2 to a 10 or 11.
When T16 is enabled, TC16H * 256 + TC16L is loaded, and T16_OUT is switched
to its initial value (CTR1, D0). When T16 counts down to 0, T16_OUT is toggled
(in Normal or Ping-Pong Mode), an interrupt (CTR2, D1) is generated (if enabled),
and a status bit (CTR2, D5) is set. See Figure 26.
Z8 Data Bus
Positive Edge
Negative Edge
HI16
CTR2 D2
LO16
IRQ3
CTR2 D4, D3
CTR2 D1
SCLK
Clock
Select
Clock
16-Bit
Counter T16
T16_OUT
Z8 Data Bus
TC16H
TC16L
Figure 26. 16-Bit Counter/Timer Circuits
Note: Global interrupts override this function as described in “Interrupts” on
page 53.
If T16 is in Single-Pass Mode, it is stopped at this point (see Figure 27). If it is in
Modulo-N Mode, it is loaded with TC16H * 256 + TC16L, and the counting contin-
ues (see Figure 28).
You can modify the values in TC16H and TC16L at any time. The new values take
effect when they are loaded.
PS019402-1103
PRELIMINARY