ht827a0 Holtek Semiconductor Inc., ht827a0 Datasheet - Page 19

• Manufacturer Part Number: ht827a0
• Description: 8-bit Microcontroller With Voice Rom
• Manufacturer: Holtek Semiconductor Inc.

Sampling rate counter
The HT827A0 offers a sampling rate counter.
This counter contains a 5 bit programmable
count-up counter. The clock may come from
128kHz or 2kHz by code option and the clock
base on 3.579545MHz system clock.
When the 128kHz clock is selected, 26 kinds of
sampling rate are provided for a voice synthe-
sizer. The following is a table of the 26 kinds of
sampling rates:
SR0~
SR4
2K/
128K
xx00 0000 3.50kHz
xx00 0001 3.61kHz
xx00 0010 3.72kHz
xx00 0011 3.86kHz
xx00 0100 3.99kHz
xx00 0101 4.14kHz
xx00 0110 4.30kHz
xx00 0111 4.48kHz
xx00 1000 4.66kHz
xx00 1001 4.86kHz
Labels
Code
¾
0~4
5
6~7 Unused bits, read as ²0²
Bit
s
Sample rate counter
Freq.
To define a voice sampling
rate or envelope decaying time
To define an input clock
source (0=128K; 1=2K)
SRC register
xx00 1101 5.89kHz
xx00 1110 6.21kHz
xx00 1111 6.58kHz
xx01 0000 6.99kHz
xx01 0001 7.46kHz
xx01 0010 7.99kHz
xx01 0011 8.61kHz
xx01 0100 9.32kHz
xx01 0101 10.17kHz
xx01 0110 11.19kHz
Function
Code
¸
Freq.
19
Note: ²xx² means don¢t care
On the other hand, when the 2kHz clock is cho-
sen, 32 kinds of time periods of the envelope de-
cay is offered.
The following is a table of the envelope decay:
Note: ²xx² means don¢t care
xx00 1010 5.08kHz
xx00 1011 5.33kHz
xx00 1100 5.59kHz
xx10 0000 54.6Hz
xx10 0001 56.4Hz
xx10 0010 58.3Hz
xx10 0011 60.3Hz
xx10 0100 62.4Hz
xx10 0101 64.7Hz
xx10 0110 67.2Hz
xx10 0111 69.9Hz
xx10 1000 72.8Hz
xx10 1001 76.0Hz
xx10 1010 79.5Hz
xx10 1011 83.2Hz
xx10 1100 87.4Hz
xx10 1101 92.0Hz
xx10 1110 97.1Hz
xx10 1111 102.8Hz xx11 1111
Code
Code
Envelope decay table
Sampling rate table
Freq.
Freq.
xx11 0000
xx11 0001
xx11 0010
xx11 0011
xx11 0100
xx11 0101
xx11 0110
xx11 0111
xx11 1000
xx11 1001
xx11 1010
xx11 1011
xx11 1100
xx11 1101
xx11 1110
xx01 0111 12.43kHz
xx01 1000 13.98kHz
xx01 1001 15.98kHz
Code
Code
March 15, 2000
HT827A0
109.3Hz
116.5Hz
124.9Hz
134.5Hz
145.7Hz
158.9Hz
174.8Hz
194.2Hz
218.5Hz
249.7Hz
291.3Hz
349.6Hz
437.0Hz
582.7Hz
874.0Hz
1.75kHz
Freq.
Freq.