Z86D86 Datasheet, PDF (60/80 Pages) Zilog, Inc. – 28-Pin Low-Voltage OTP Microcontroller

Z86D86
28-Pin Low-Voltage OTP Microcontroller
52
If D6 of CTR2 Is 1
T16 ignores the subsequent edges in the input signal and continues counting
down. A time-out of T8 causes T16 to capture its current value and generate an
interrupt if enabled (CTR2, D2). In this case, T16 does not reload and continues
counting. If the D6 bit of CTR2 is toggled (by writing a 0 and then a 1 to it), T16
captures and reloads on the next edge (rising, falling, or both, depending on
CTR1, D5, D4), thereby continuing to ignore subsequent edges.
This T16 mode is generally used to measure mark time, defined by the length of
time between active carrier signal bursts (marks).
When T16 reaches 0, it continues counting from FFFFh. Meanwhile, a status bit
(CTR2, D5) is set, and an interrupt time-out can be generated if enabled (CTR2,
D1).
Ping-Pong Mode
This operation mode (see Figure 42) is only valid in transmit mode. T8 and T16
must be programmed in Single-Pass Mode (CTR0, D6; CTR2, D6), and Ping-
Pong Mode must be programmed in CTR1, D3, D2. You can begin the operation
by enabling either T8 or T16 (CTR0, D7 or CTR2, D7). For example, if T8 is
enabled, T8_OUT is set to this initial value (CTR1, D1). According to T8_OUT's
level, TC8H or TC8L is loaded into T8. After the terminal count is reached, T8 is
disabled, and T16 is enabled. T16_OUT switches to its initial value (CTR1, D0),
data from TC16H and TC16L is loaded, and T16 starts to count. After T16 reaches
the terminal count, it stops, T8 is enabled again, and the entire cycle repeats.
Interrupts can be allowed when T8 or T16 reaches terminal control (CTR0, D1;
CTR2, D1). To stop the Ping-Pong operation, write 00 to bits D3 and D2 of CTR1.
Note: Enabling Ping-Pong operation while the counter/timers are
running might cause intermittent counter/timer function. Disable
the counter/timers and then reset the status flags before
instituting this operation.
PS008905-0105
PRELIMINARY