HT827A0 Datasheet, PDF (22/49 Pages) Holtek Semiconductor Inc – 8-Bit Microcontroller with Voice ROM

HT827A0
Labels (TMRC)
¾
TE
TON
¾
TM0
TM1
Bits
Function
0~2 Unused bits, read as ²0²
3
To define the TMR active edge of a timer/event counter
(0=active on low to high; 1=active on high to low)
4 To enable/disable timer counting (0=disabled; 1=enabled)
5 Unused bits, read as ²0²
To define the operation mode
6
7
01=Event count mode (external clock)
10=Timer mode (internal clock)
11=Pulse width measurement mode
00=Unused
TMRC register
Tone and melody generator
The HT827A0 provides a tone frequency register
(TONE; 2AH), beat frequency register (BEAT;
28H) as well as tempo frequency register
(TEMPO; 29H) for generating melody and sound
effects.
The chip can generate four octaves, labeled
from C2^# to C6. Desired frequencies can be ob-
tained by first writing the related data into a
tone frequency register (TONE; 2AH) and then
enabling the tone counter. A Tone frequency is
generated and remained if the tone counter
overflows.
Labels Bits
Function
TN0~
TN3
To define the tone frequency
0~3 (refer to the tone frequency
table)
OCT0
OCT1
4
5
To define the 4 octave tone
frequencies (refer to the
tone frequency table)
¾
6 Unused bit, read as ²0²
TEN
To enable/disable the tone
7 counter
(0= disabled; 1= enabled)
TONE register
T o n e R e g is te r
D ATA BU S
T o n e F re q u e n c y
P L A T a b le
128kH z
TEN
T o n e C o u n te r
T o n e F re q u e n c y
TONE counter
The BEAT register counts melody beats. Bit 7
(BTO) of the BEAT register is set when the beat
counter overflows. No interrupt is generated if
the beat counter overflows. So bit 7 (BTO) of the
BEAT register must be polled to generate correct
beat frequencies. After reading the BTO status,
the bit 7 should be cleared by the programmer to
avoid malfunction of the next polling.
Labels Bits
Function
B0~B6
To define the beat frequency
0~6 (refer to the beat frequency
table)
BTO
7
BTO is set during beat
counter time-out
BEAT register
22
March 15, 2000