ht82m9be Holtek Semiconductor Inc., ht82m9be Datasheet - Page 15

• Manufacturer Part Number: ht82m9be
• Description: Ht82m99e/ht82m99a -- Usb Mouse Encoder 8-bit Mcu
• Manufacturer: Holtek Semiconductor Inc.

operate until overflow occurs (a Timer/Event Counter 0/1
reloading will occur at the same time). When the
Timer/Event Counter 0/1 (reading TMR0/TMR1) is read,
the clock will be blocked to avoid errors. As clock blocking
may results in a counting error, this must be taken into
consideration by the programmer.
Input/Output Ports
There are 20 bidirectional input/output lines in the
microcontroller, labeled from PA to PC, which are
mapped to the data memory of [12H], [14H] and [16H]
respectively. All of these I/O ports can be used for input
Rev. 1.60
Timer/Event Counter 0
Timer/Event Counter 1
Input/Output Ports
15
and output operations. For input operation, these ports
are non-latching, that is, the inputs must be ready at the
T2 rising edge of instruction MOV A,[m] (m=12H, 14H
or 16H). For output operation, all the data is latched and
remains unchanged until the output latch is rewritten.
Each I/O line has its own control register (PAC, PBC and
PCC) to control the input/output configuration. With this
control register, CMOS/NMOS/PMOS output or Schmitt
trigger input with or without pull-high/low resistor struc-
tures can be reconfigured dynamically under software
control. To function as an input, the corresponding latch
of the control register must write a 1 . The input source
HT82M9BE/HT82M9BA
April 16, 2008