Z86L88 Datasheet, PDF (59/80 Pages) Zilog, Inc. – INFRARED REMOTE CONTROLLERS

Z86L88
Low-Voltage IR 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) but continues to ignore subsequent edges.
This T16 mode is generally used to measure mark times, the length of active car-
rier signal bursts.
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 41) 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 and 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 termi-
nal count, it stops, T8 is enabled again, and the whole 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.
19-4614; Rev 0; 4/09