ZLF645 MAXIM [Maxim Integrated Products], ZLF645 Datasheet - Page 119

• Manufacturer Part Number: ZLF645
• Description: Flash MCUs with Learning Amplification
• Manufacturer: MAXIM [Maxim Integrated Products]

19-4572; Rev 0; 4/09
Note:
PING-PONG Mode
If Bit 6 of CTR2 Is 0—
CTR1 bits [5:4]) is detected during counting, the current count in T16 is complemented
and loaded into HI16 and LO16. When data is captured, one of the edge detect status bits
(CTR1, bit 1; bit 0) is set, and an interrupt is generated if enabled (CTR2, Bit 2). T16 is
loaded with
time, the length of time between bursts of carrier signal (marks).
If Bit 6 of CTR2 Is 1—
counting down. A time-out of T8 causes T16 to capture its current value and generate an
interrupt if enabled (CTR2, Bit 2). In this case, T16 does not reload and continues count-
ing. If CTR2 bit 6 is toggled (by writing a 0 then a 1 to it), T16 captures and reloads on the
next edge (rising, falling, or both depending on CTR1 bits [5:4]), continuing to ignore sub-
sequent edges. This T16 mode generally measures mark time, the length of an active car-
rier signal burst.
If T16 reaches 0, T16 continues counting from
5) is set, and an interrupt time-out can be generated, if enabled (CTR2 bit 1).
PING-PONG mode is only valid in TRANSMIT mode. T8 and T16 must be programmed
in SINGLE-PASS mode (CTR0, bit 6; CTR2, bit 6), and PING-PONG mode must be pro-
grammed in CTR1 bits [3:2]. 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, bit 1).
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 then switches to its initial value
(CTR1, bit 0), data from TC16H and TC16L is loaded, and T16 starts to count. After T16
reaches the terminal count, it stops, T8 is enabled again, repeating the entire cycle. Inter-
rupts can be allowed when T8 or T16 reaches terminal control (CTR0, bit 1; CTR2, bit 1).
To stop the PING-PONG operation, write 00 to bits CTR1 bits [3:2]. See
page 112.
Enabling PING-PONG operation while the counter/timers are running may cause
intermittent counter/timer function. Disable the counter/timers and reset the status flags
before instituting this operation.
FFFFh
and starts again. This T16 mode is generally used to measure space
When a subsequent edge (rising, falling, or both depending on
T16 ignores the subsequent edges in the input signal and continues
FFFFh
. Meanwhile, a status bit (CTR2 bit
ZLF645 Series Flash MCUs
Counter/Timer Functional Blocks
Product Specification
Figure 38

on
111