Z86D99 ZILOG [Zilog, Inc.], Z86D99 Datasheet - Page 41

• Manufacturer Part Number: Z86D99
• Description: Low-Voltage Micro controllers with ADC
• Manufacturer: ZILOG [Zilog, Inc.]

Z86D990/Z86D991 OTP and Z86L99X ROM
Low-Voltage Microcontrollers with ADC
34
Figure 17. I-V Characteristics for the Current Sink Pad P43
The CPU reads the mode of the pad driver by reading bit number 2 from the LB
register. This bit is the output of a Set-Reset flip-flop that sets whenever the volt-
age on the pad is lower than V
and is reset by a CPU write to the respective
outmin
register.
T1 Timer
The Z86D99/Z86L99 family provides one general-purpose 8-bit counter/timer, T
,
1
driven by its own 6-bit prescaler, PRE
. The T
counter/timer is independent of the
1
1
processor instruction sequence, which relieves software from time-critical opera-
tions such as interval timing and event counting.
The T
counter/timer operates in either single-pass or continuous mode. At the
1
end-of-count, counting either stops or the initial value is reloaded and counting
continues. Under software control, new values are loaded immediately or when
the end-of-count is reached. Software also controls the counting mode, how the
counter/timer is started or stopped, and the counter/timer’s use of I/O lines. Both
the counter and prescaler registers can be altered while the counter/timer is run-
ning.
PS003807-1002
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