Rainbow Electronics HT49R70A-1 - Manual (Page 24)

HT49R70A-1
Rev. 1.00 24 December 4, 2001
Options
Pull-high selection. This option is to decide whether the pull-high resistance is visible or not on the PA0~PA3 and PC.
(PB and PA4~PA7 are always pull-high)
PA0~PA3 and PC0~PC7 CMOS or NMOS selection.
The structure of PA0~PA3 and PC0~PC7 can be selected as CMOS or NMOS individually. When the CMOS is se-
lected, the related pins only can be used for output operations. When the NMOS is selected, the related pins can be
used for input or output operations. (PA4~PA7 are always NMOS)
Clock source selection of Timer/Event Counter 0. There are two types of selections: system clock or system clock/4.
Clock source selection of Timer/Event Counter 1. There are three types of selections: TMR0 overflow, system clock
or Time Base overflow.
I/O pins share with other function selections.
PA0/BZ, PA1/BZ: PA0 and PA1 can be set as I/O pins or buzzer outputs.
PA3/PFD: PA3 can be set as I/O pins or PFD output.
LCD common selection. There are three types of selections: 2 common (1/2duty) or 3 common (1/3duty) or 4 com-
mon (1/4duty). If the 4 common is selected, the segment output pin
²SEG40² will be set as a common output.
LCD bias power supply selection
There are two types of selections: 1/2bias or 1/3bias
LCD bias type selection
This option is to determine what kind of bias is selected, R type or C type.
LCD driver clock selection. There are seven types of frequency signals for the LCD driver circuits: f
S
/2 2 ~f
S
/2 8 . ²F
S
²
stands for the clock source selection by options.
LCD ON/OFF at HALT selection
LVR selection
LVR has enable or disable options
LVD selection
LVD has enable or disable options
PFD selection
If PA3 is set as PFD output, there are two types of selections; One is PFD0 as the PFD output, the other is PFD1 as
the PFD output. PFD0, PFD1 are the timer overflow signals of the Timer/Event Counter 0, Timer/Event Counter 1 re-
spectively.