Z86D86 Datasheet, PDF (58/80 Pages) Zilog, Inc. – 28-Pin Low-Voltage OTP Microcontroller

Z86D86
28-Pin Low-Voltage OTP Microcontroller
50
Sixteen-Bit Counter/Timer Circuits
Figure 39 shows the 16-bit counter/timer circuits.
Z8 Data Bus
Pos Edge
Neg Edge
HI16
CTR2 D4, D3
SCLK
Clock
Select
Clock
16-Bit
Counter
T16
CTR2 D2
LO16
IRQ3
CTR2 D1
T16_OUT
Z8 Data Bus
TC16H
TC16L
Figure 39. 16-Bit Counter/Timer Circuits
T16 Transmit Mode
In Normal or Ping-Pong Mode, the output of T16, when not enabled, is dependent
on CTR1, D0. If the result 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 pro-
gramming 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 is generated if enabled (CTR2, D1),
and a status bit (CTR2, D5) is set.
Note: Global interrupts override this function as described in
“Interrupts” on page 54.
If T16 is in Single-Pass Mode, T16 is stopped at this point (see Figure 40). If T16
is in Modulo-N Mode, T16 is loaded with TC16H * 256 + TC16L and the counting
continues (see Figure 41).
PS008905-0105
PRELIMINARY